Aus dem Institut für Tierzucht und Tierhaltung

der Agrar- und Ernährungswissenschaftlichen Fakultät

der Christian-Albrechts-Universität zu Kiel

SOWS’ MATERNAL BEHAVIOUR AS A MAJOR

INFLUENCE ON THE SURVIVAL OF PIGLETS

Dissertation

zur Erlangung des Doktorgrades

der Agrar- und Ernährungswissenschaftliche Fakultät

der Christian-Albrechts-Universität zu Kiel

vorgelegt von

Master of Science

DIANE WISCHNER

aus Ibbenbüren, Nordrhein-Westfalen

Dekan: Prof. Dr. U. Latacz-Lohmann

Erster Berichterstatter: Prof. Dr. J. Krieter

Zweiter Berichterstatter: Prof. Dr. E. Schallenberger

Tag der mündlichen Prüfung: 28. April 2009

Die Dissertation wurde mit dankeswerter finanzieller Unterstützung der H. Wilhelm

Schaumann Stiftung und der Innovationsstiftung Schleswig-Holstein angefertigt.

TABLE OF CONTENTS

GENERAL INTRODUCTION

.....................................................................................................................................................1

CHAPTER ONE

Nest-building behaviour in sows and consequences for pig husbandry

……………………………………………………………………………………………….....3

CHAPTER TWO

Characterisation of sows’ postures and posture changes with regard to crushing piglets

………………………………………………………………………………………………...27

CHAPTER THREE

Pre-lying behaviour patterns in confined sows and their effects on crushing of piglets

………………………………………………………………………………………………...47

CHAPTER FOUR

Analysis of sows’ posture patterns in relationship to different behavioural tests of sows

………………………………………………………………………………………………...63

GENERAL DISCUSSION

………………………………………………………………………………………………...77

GENERAL SUMMARY

………………………………………………………………………………………………...91

ZUSAMMENFASSUNG

………………………………………………………………………………………………...95

0

1

GENERAL INTRODUCTION

Piglet mortality is the key factor in sow reproduction and the basis for economically

successful piglet rearing. However, measures applied in sow management often represent a

challenge with regard to animal welfare. Up to 15% of piglets born alive may die before

weaning (Blackshaw et al., 1994). A large proportion of piglets’ pre-weaning deaths occur

during farrowing and in the first 48 h after parturition (Barnett et al., 2001). Crushed piglets

represent one of the most important factors limiting sow productivity and are also a great

obstacle in any attempt to improve animal welfare (Arey and Sancha, 1996). The risk of

crushing by the sow is associated with the proximity between the dam and her offspring

necessary for adequate colostrum intake and the provision of warmth within the first few days

after birth (Cronin and Smith, 1992). Grandinson (2005) described the maternal behaviour of

sows as an important component of maternal success, increasing the welfare of both the

piglets and the sow and improving the survivability of the offspring. One aim of the

traditional farrowing crate has been the restriction of the sow’s movement patterns in order to

reduce pre-weaning mortality, and crushing in particular (Edwards and Fraser, 1997). The

restraint nature of the crate decreased the responsibility of the sows to take care of their

offspring (Andersen et al., 2005).

The aim of this thesis was to investigate the behavioural background of different traits to

characterise the maternal behaviour of crated sows, in particular the locomotory behavioural

pattern, in relationship to crushing piglets. All traits were recorded by video on one farm in

order to reduce environmental influences.

The first chapter provides a review of the ‘nest-building’ behaviour of sows because

prepartal behaviour of sows is mainly characterised by ‘nest-building’ activities. ‘Nest-

building’ behaviour does not significantly change due to domestication and remains part of

the natural behaviour pattern in different housing systems. Possibilities to perform this

behaviour in different housing systems, considering the increased demands for animal

welfare, were discussed.

In the second chapter, the posture patterns of sows are analysed in relationship to crushing

piglets. The frequency, the duration and the manner of different movement patterns of

important pre- and post-farrowing behaviour are investigated to determine differences in

2

maternal protectiveness of sows that had crushed piglets or sows that had not crushed any

piglet.

The third chapter focuses on components of ‘pre-lying’ behaviour of sows and the relation

to crushing piglets. The individual responsiveness of sows is evaluated by the analysis of

various behavioural patterns indicating the interaction between the sow and the piglets with

regard to critical movements and piglet activity.

The fourth chapter presents behavioural tests and their relationship to the locomotory

behaviour of sows. Differences in posture patterns and maternal protectiveness were assessed

by tests and recorded by video in the study in order to develop behavioural traits that indicate

the sow’s mothering ability.

References

Andersen, I.L., Berg, S., Bøe, K.E., 2005. Crushing of piglets by the mother sow (Sus scrofa)-

purely accidental or a poor mother? Appl. Anim. Behav. Sci. 93, 229-243.

Arey, D.S., Sancha, E.S., 1996. Behaviour and productivity of sows and piglets in a family

system and in farrowing crates. Appl. Anim. Behav. Sci. 50, 135-145.

Barnett, J.L., Hemsworth, P.H., Cronin, G.M., Jongman, E.C., Hutson, G.D., 2001. A review

of the welfare issues for sows and piglets in relation to housing, Aust. J. Agric. Res.

52, 1-28.

Blackshaw, J.K., Blackshaw, A.W., Thomas, F.J., Newman, F.W., 1994. Comparison of

behaviour patterns of sows and litters in a farrowing crate and a farrowing pen. Appl.

Anim. Behav. Sci. 39, 281-295.

Cronin, G.M., Smith, J.A., 1992. Suckling behaviour of sows in farrowing crates and straw-

bedded pens. Appl. Anim. Behav. Sci. 33, 175-189.

Edwards, S.A., Fraser, D., 1997. Housing systems for farrowing and lactation. Pig J. 39, 77-

89.

Grandinson, K., 2005. Genetic background of maternal behaviour and its relation to offspring

survival. Livest. Prod. Sci. 93, 43-50.

3

CHAPTER ONE

Nest-building behaviour in sows and consequences for pig husbandry

Diane Wischner, Nicole Kemper and Joachim Krieter

Institute of Animal Breeding and Husbandry, Christian-Albrechts-University,

24098 Kiel, Germany

Published in Livestock Science, 2009 124: 1-8

4

Abstract

Patterns of maternal behaviour are strongly related to reproductive abilities in sows. Prepartal

behaviour of sows is mainly characterised by nest-building activities, resulting in a nest that

provides shelter for the piglets. In the course of domestication, sows have not lost their

instinctive behaviour to nest-build, but perform at least elements of it when appropriate space

and materials are available. The onset and performance of nest-building is both stimulated

internally via hormones and externally via feedback from the environment. With this

environmental influence, the possibilities to perform nest-building can be restricted to

different extents in commercially farmed pigs. The aim of the present review is to point out

the sow’s need for nest-building performance as part of the natural behaviour pattern,

although they are kept in different modern housing systems. With regard to increased

demands for animal welfare and following changes in the legislation for pig husbandry,

possible consequences for different housing systems are discussed.

Keywords

Reproduction; Crates; Maternal behaviour; Piglets; Pens

1. Introduction

In modern pig husbandry, the ability of the sow to raise large litters and to meet the piglets’

needs especially with regard to milk provision is essential. To reduce piglet losses and to

facilitate human intervention, farrowing crates have been developed. In comparison to

alternatives systems like pens, farrowing crates restrain the sow’s movements during

parturition and lactation and have mainly been intended to protect piglets from being crushed

(Robertson et al., 1966; Edwards and Fraser, 1997). With this restriction, the performance of

typical reproductive behaviour like an increased activity one to two days before farrowing

(Jensen 1986), as seen in free-ranging sows, is limited in commercially farmed pigs. One

important behavioural trait before the onset of parturition is nest-building as well in

domesticated, feral and wild sows. Nest-building behaviour is specific and unique in members

of the family Suidae, including the pig (Sus scrofa) (Lent, 1974). This behavioural pattern

characterises the pig as ‘hiders’ (Lent, 1974), or more specifically as ‘nest dwellers’ (Stangel

and Jensen, 1991). Nest-building is performed to provide the offspring with shelter and

comfort, particularly with respect to thermoregulation. Due to a lack of brown fat tissue, the

piglets demand an increased surrounding temperature (Myrcha and Jezierski, 1972; Varley

and Stedmann, 1994). Their physiological thermoregulation is still developing, particularly

5

during the first two weeks (Hurnik, 1985). Moreover, compared to other even-toed ungulates,

piglets are rarely born with hair, and have an unfavourable surface-weight proportion,

weighing less than 1% of their adult weights (Mayer et al., 2002). Thermoregulation is closely

related to birth weight. The maintenance of the homeothermic balance in the cold is reduced

in smaller piglets due to the greater surface to body mass ratio resulting in higher heat losses

(Herpin et al., 2002). Without protection against climatic influences, the piglets would cool

down and die. By providing a microclimate with protection against other weather effects, the

nest supports the new-born piglet to perform thermoregulation and to limit rapid heat loss

(Briedermann, 1986). Moreover, it offers protection against weather and predators (Pullar,

1953). In addition, piglets are kept close to the sow and away from the family group. In this

way, it is ensured that the piglets are not trampled by other adults and that other piglets do not

steal milk from the sow (Jensen, 1986).

Regarding the duration of staying in the nest, the classification of piglets as altricial or

precocial animals is discussed controversially. Fraser (1980) classified them as precocial

animals, even though they are born in large litters and spend their first days of life in the nest.

On the contrary, the classification as altricial animals is justified by the long period up to

seven days spent in the nest (Jensen and Redbo, 1987). This is also indicated by the fact that

no rapid individual bonds with the offspring are performed, as this is not essential for nesting

animals (Kilgour, 1985). Sows usually do not lick the newborn or server the umbilical cord

(Randall, 1972; Fraser, 1984) and are passive during farrowing until the last piglet is born

(Stangel and Jensen, 1991). On the contrary, Stangel and Jensen (1991) reported cases of

sows cleaning their piglets and consuming their afterbirths. To compound the oppositional

views, Portmann (1960) suggested the term ‘secondary precocial’ to describe the piglets’

behaviour.

In the course of domestication and the associated reduced variability of the environment, sows

have lost the need for protection against climatic influences, starvation and predators, as

stated by Lindsay (1985). However, this position ignores the fact that extensive farming with

free-roaming, domesticated animals is practised in many countries, still exposing them to

various influences. Even though the influences of domestication on some behaviour patterns

can not be denied, sows in extensive housing still show behaviour more or less identical with

that of wild boars when nesting material and sites are provided (Gustafsson et al., 1999). This

paper reviews the pre-farrowing nest-building behaviour of sows in different housing systems

and the possible consequences for pig husbandry.

6

2. Nest-building behaviour under natural or semi-natural environments

Both genders build and use modified nests and beds for resting and loafing (Martys, 1982).

Therefore, it is possible to divide nests into sleeping nests, ‘mock’ nests (Jensen, 1986) and

farrowing nests (Pfeffer, 1959), but only the latter are the object of this review.

In general, pigs investigate their surroundings by rooting, sniffing, biting and chewing on

digestible and also indigestible items (Studnitz et al., 2007). Nest-building is a modification of

this behaviour with the aim to build a nest as shelter. It is a pre-defined, inherited behavioural

fixed action pattern shown both in male and female pigs (Eibl-Eibesfeldt, 1963). Nest-

building behaviour of mammals represents an innate behaviour. Sign stimuli are necessary to

perform this behaviour pattern. They represent an important starting point for the behaviour

chain, determining and controlling the behaviour patterns ante and post partum, including the

care of the offspring (Buß, 1972). It is shown as well in inexperienced as in experienced

animals and does not have to be learnt (Lorenz, 1937). However, sows can learn how to build

a better nest and improve by experience with each litter (Jensen et al., 1987).

Grandin and Deesing (1998) describe nest-building in sows as an example of the interaction

between instinct and learning. Age or experience modifies nest-building behaviour (Jensen,

1989) as well as the interaction with the farrowing environment (Thodberg et al., 1999).

Already at an age of six days, piglets perform basic elements of nest-building behaviour

(Gundlach, 1968). In experiments, isolated piglets perform nest-building behaviour earlier to

maintain their thermoregulation (Gundlach, 1968).

Nest-building behaviour is one important part in the whole process of pre and post partum

maternal behaviour. During the total life-span of a sow, pre-farrowing nest-building

behaviour is only performed a few times with each new pregnancy and parturition to come.

Under natural conditions, the sow limits her scope of action to a smaller home range within

the last month of pregnancy and shows reduced activity (Kurz and Marchinton, 1972). One to

three days prior to parturition the sow separates from the group and becomes solitary,

exploring her surroundings for a suitable place to build the nest (Hafez et al., 1962; Buß,

1972; Jensen, 1986; Stolba and Wood-Gush, 1989). The sow travels distances up to 6.5 km

within 6 hours and stops at several places to explore the ground by sniffing and rooting

(Jensen, 1986). Compared to grass areas, forest or forest border habitats are preferred as nest-

sites (Stolba and Wood-Gush, 1984). Favoured sites are often situated below a slope and

characterised by offering shelter against rain and wind, for instance under dense vegetation,

probably in the form of a roof of branches hanging down (Gundlach, 1968; Frädrich, 1974,

Stolba and Wood-Gush, 1984). These places allow an open view and provide cover on two

7

sides (Stolba and Wood-Gush, 1984). The ground is often well-drained soil and easy to root

(Jensen, 1986). Jensen (1986) reported in free-ranging sows the occurrences of ‘mock nests’.

These nests were built up like farrowing nests, but they were not used. A change in

temperament towards unpredictable aggression, even against their own previous progeny, can

be observed (Graves, 1984) as well as increased restlessness (Jones, 1966). Experienced

mothers seem to be calmer than primiparae (Signoret et al., 1975). Baxter (1982) also

reported fearfulness or agitation in gilts rather than in experienced sows.

Generally, the sow starts to build the nest at approximately 24 h before parturition, showing

most intensive activity 12 to 6 h before farrowing (Jensen, 1989; Cronin et al., 1994; Haskell

and Hutson, 1994; Algers and Uvnäs-Moberg, 2007). Nest-building in wild boars as well as in

domestic sows can be roughly classified in two consecutive phases: initially, in the first phase,

the ground is rooted and pawed and a shallow hole is dug. In the second phase, the sow

collects, carries and arranges the nest material along the edges of and in the nest (Jensen,

1993). In more detail, the sow roots and digs the ground by throwing the soil with her mouth

and head (Gundlach, 1968). She gathers nest-building material, mainly consisting of

branches, bushes and other organic material, from within a radius of 20 m (Mayer et al., 2002)

and 50 m around the nest (Gundlach, 1968). The gathered material includes dry grass and

leaves (Gundlach, 1968), as well as fern and moss (Snethlage, 1967).

Younger and smaller sows have a smaller radius for gathering compared to older and larger

sows (Jensen, 1989; Mayer et al., 2002). Gathering is performed by breaking and biting of the

material, shuffling it in the mouth and carrying it to the nest site. The sow deposits the

material along the edges of the nest and, by turning her body round in circles with repeated

pawing and pressing her head against the material, the edges of the nest are distinctly elevated

(Gundlach, 1968). The sow fills the nest with further material by throwing smaller parts with

head turns in the middle of the nest and distributes them by turning around herself.

Stabilisation of the whole nest is achieved by integrating thick branches and twigs, which

partially protrude over the side of the nest. After covering with finer material, such as grass,

leaves and small twigs, the nest shows a stratified structure with a loose grass heap up to one

metre high and includes smaller and larger wooden parts (Gundlach, 1968).

In the finished nest, the sow keeps the material together by pawing and pushing it back with

her snout. In this way, sows gradually construct an oval nest with positively correlated length

and width (Mayer et al., 2002). In few cases, dome-like nest coverings have been reported

(Briedermann, 1986). The sow usually leaves the nest at a certain side, and sometimes covers

the nest with more material before leaving on foraging trips (Tisdell, 1982).

8

2.1. Influences on nest-building performance

Nest-building behaviour is both influenced by internal and external stimuli. The appropriate

combination of all modulating endogenous and exogenous stimuli decides whether complete

and successful nest-building will take place. With regard to these influencing stimuli, two

nest-building behaviour elements can be distinguished. The initial phase of site searching and

hole digging is regulated by internal hormonal changes, while the second, material-oriented

phase is mainly dependent on external stimuli such as feedback from the nest site (Jensen,

1993). Hutson (1988) indicated that a successful completion of each phase is the stimulus for

the next phase, like a chain or cascade of response.

Several stimuli are discussed as the starting point of this chain in the first phase. For instance,

Gilbert et al. (2001) suggested that some sort of signal, resulting from foetal maturation,

might initiate the cascade for nest-building behaviour. In more detail, the hormonal impact on

maternal behaviour in pigs was reported by Algers and Uvnäs-Moberg (2007). In short, the

onset of nest-building seems to be triggered by a rise in prolactin level (Widowski et al.,

1990; Castrén et al., 1993). This rise itself is induced by a decrease in progesterone and an

increase in prostaglandin (Ellendorff et al., 1979; Burne et al., 2001b; Algers and Uvnäs-

Moberg, 2007). Nest-building behaviour can be induced by the administration of

prostaglandin PGF2α injections in pregnant sows (Widowski and Curtis, 1989). On the

contrary, injection of the prostaglandin synthesis inhibitor indomethacin to late pregnant gilts

reduces nest-building behaviour (Gilbert et al., 2001). The cessation of nest-building has been

suggested to be strongly correlated with the dramatic rise in oxytocin levels 4 h prior to

parturition (Castrén et al. 1993). Whether the effect of oxytocin, leading to frequent uterine

contractions (Gilbert et al., 1994), stops nest-building or whether oxytocin induces the

cessation at a central level still remains unknown (Algers and Uvnäs-Moberg, 2007).

The second phase, depending on external stimuli, is termed as the material-oriented phase

(Jensen 1988a). To continue the reaction chain, the sow is reliant on feedback and external

stimuli. Stimuli are provided by proper nest material and therefore the availability of suitable

nest material is crucial. This provision again is strongly determined by the material’s

suitability to stake, stuff and protect (Arey et al., 1991). The more suitable the material, the

sooner nest-building is completed. For example, with access to branches, gilts terminate their

nest-building sooner than without (Damm et al., 2000). Arey et al. (1991) also showed that

the environment provided (e.g. provision of pre-formed nests) altered nest-building

behaviour. Widowski and Curtis (1990) reported that the behaviour was directed by the

nesting material as stimulus but the structure of the nesting material did not affect the activity

9

of the sows. Stolba and Wood-Gush (1984) described that ‘high standing stalks’ release the

behaviour. Therefore, it can be assumed that the presence of nesting material triggers nest-

building behaviour in motivated sows. On the other hand, Hutson (1988) and Blackshaw

(1983) claimed that nesting-material is of no importance to sows ante partum. However,

Baxter (1983) hypothesised that there is a feedback stimulus to stop nest-building behaviour

which was achieved via sufficient ‘udder comfort’ with a comfortable and flexible lying

substrate area in the nest.

Habitat and season do not only influence the vegetation and thereby the nesting material, but

there is evidence that nest-building behaviour is affected directly by season due to

environmental temperatures (Dellmeier and Friend, 1991). The duration and intensity appears

to vary with weather conditions and may be observed less frequently during hot summer

weather (Damm et al., 2000). With decreasing temperatures, there is a significant increase in

rooting and nest-building behaviour (Burne et al., 2001a).

However, external factors are not solely responsible for behavioural patterns in the material-

oriented phase; internal, endocrine changes can influence and alter the sensitivity to external

stimuli as well (Haskell and Hutson, 1994). For oxytocin, an anti-stress effect promoting

calmness and reduced anxiety is described by Uvnäs-Moberg et al. (2001), but the detailed

interplay of these factors still has to be investigated.

2.2. Influences of domestication

Buß (1972) described various morphological, physiological and psychological changes in the

course of domestication which resulted in behavioural characteristics. Behavioural and other,

especially physiological, changes caused by domestication are often based on innate

behaviour (Lorenz, 1959). Stressors, such as those usually experienced in the natural

environment, are limited in surroundings where locomotion is reduced as food is supplied and

protection against predators is given (Lorenz, 1959). Modification of old phylogenetic

behavioural elements allows new variances of behavioural patterns, for example, a shortened

flight distance. Increased variability in these patterns is reported in domestic animals (Schulz-

Scholz, 1963). As a consequence, a possible alteration of nest-building behaviour in

domesticated pigs could be assumed. Therefore, the argument that modern sows do not

necessarily build nests due to domestication has been used to doubt confinement in farrowing

crates (Algers and Uvnäs-Moberg, 2007). These housing systems, established since the late

1950s, were designed to minimise piglet losses by crushing and to improve management

(Edwards and Fraser, 1997). Additionally, Grauvogel (1958) postulated that a ‘nest feeling’ is

10

provided by the enclosed crate and no negative effects on the sows have to be expected. First

studies on nest-building behaviour in domestic pigs under semi-natural conditions were

investigated in the 1980s (Stolba and Wood Gush, 1989; Jensen, 1986; Algers and Jensen,

1990). Domestic sows, even with experience of four farrowings in confinement, were able to

build nests identical to those of wild boars (Gustafsson et al., 1999). This led to the

conclusion that domestication has not given rise to any changes in the performance of nest-

building behaviour. Due to only few differences between maternal behaviour in wild and

domesticated sows, Mignon-Grasteau et al. (2005) suggested that maternal behaviour is

relatively robust in pigs. This statement is supported by Jensen (2002) who described similar

behaviour patterns for free-ranging sows and wild boars. On the contrary, Price (1999)

mentioned behavioural changes associated with the process of domestication. Through

selection, inbreeding and genetic drift animals have been domesticated and forced to adapt to

the provided housing and management. Given this adaptation, it might be expected that

because nest-building is no longer needed, its associated behaviour would have vanished.

However, domestication has not given rise to major changes in the performance of nest-

building behaviour. This fact clearly underlines how innate this behaviour is, and highlights

its importance.

3. Nest-building behaviour in different housing systems

All elements of nest-building are performed by female pigs in their environment as far as

possible (Hutson and Haskell, 1990; Jensen and Toates, 1993). In commercially farmed pigs,

maternal behaviour is usually strongly restricted (von Borell et al., 2007). In order to reduce

piglet losses due to crushing, and to facilitate human intervention, systems to control sow

movement were developed and farrowing crates were introduced on a large scale (Fraser and

Broom, 1990; Edwards, 2002). Different types and systems have been created since then, but

most of them without considering the natural periparturient behaviour of sows (Damm et al.,

2003).

3.1. Housing in crates

Farrowing crates and concrete floors prevent much of the nest-building behaviour, but many

of the motor elements are still present. In intensive pig production, most exogenous stimuli

are excluded and in most cases only provided if regulated by legislation. In confinement,

feedback from the nest site, necessary to continue successful nest-building in the material-

oriented phase, is and can lead to prolonged, but futile nest-building motivation (Damm et al.,

11

2000; 2003). In general, nest-building-like behaviour is shown, even in absence of exogenous

stimuli. However, compared to sows housed in pens, nest-building in crates is performed only

in a small variation and in more fragmented and longer phases (Damm et al., 2003). In the

crates, animals may grind their teeth, bite and root at the rails and change position frequently

between standing and lying (Heck et al., 1988). In comparison to a turn-around crate and an

open pen, frequency and duration of standing is greatest in the standard crate and increase

gradually until the sow changes position every few minutes (Heck et al., 1988). Sows housed

in farrowing crates stand up more often before the onset of parturition compared to sows in

pens (Hansen and Curtis, 1980). These activities are accompanied by intermittent grunting,

champing of the jaws and increased respiratory rate (Heckt et al., 1988). Rooting with the

nose and pawing with the front hooves is shown by sows on concrete floor during ‘nest’

preparation (Hartsock and Barczewski, 1997; Thodberg et al., 1999). Heckt et al. (1988) and

Cronin et al. (1994) reported that crated gilts tended to paw more than gilts in open pens. The

sow’s drive to gather nesting material with the mouth results in rooting and mouthing pipes

and waterers, as only these items are available for oral manipulation (Hartsock and

Barczewski, 1997). In a study dealing with sows in crates and pens, the increase of plasma

cortisol as stress indictor in crated sows was related to the interruption of pre-parturient

behaviour like nest-building (Lawrence et al., 1997). Pre-partal stress may be coupled with

slow parturition and lactation problems (Poe, 1960). Event though the adaption to the

behavioural restriction in crates increases from parity to parity, this adaptation has not

completely reduced the elevation of stress hormones (Jarvis et al., 2001). Of course it has to

be considered that parturition itself influences the release of stress-indicators like cortisol

(Lawrence et al., 1994). In general, confined sows show increased activity (Jarvis et al., 2001)

and substrate directed-behaviour like interacting with floor and fixtures of the crate

(Lawrence et al., 1997). As further possible indicators of stress or frustration, oral or nasal

stereotypes are described, such as bar biting (Jensen, 1988b), repetitive pressing of the snout

against a surface (Vestergaard, 1984), and straw chewing (Grauvogel, 1958; Horrel et al.,

2001). Distinguishing between stereotypes and indirect nest-building behaviour is difficult,

since biting and chewing on systemic equipment may be analogous to the act of gathering and

carrying branches and twigs to the nest (Jensen, 1993; Hartsock and Baczewski, 1997).

Farrowing in crates tends to be more stressful than in pens, even if adaptation to the crate

environment occurs (Jarvis et al., 2001). Unsatisfied behavioural needs and idle activities can

cause injuries and apparent exhaustion in the sow (Hansen and Curtis, 1980). Additionally,

the lack of feedback can result in higher heart rates before farrowing (Jensen and Toates,

12

1993). Environmental stress of sows inhibits oxytocin and this may compromise the welfare

of the sow and the piglet, because oxytocin influences the maternal behaviour (Jarvis et al.,

1997). Jarvis et al. (2004) found no relationship between space or substrate and oxytocin, but

a positive relationship between oxytocin and unresponsiveness to piglets. Furthermore, Jarvis

et al. (2004) described lower levels of oxytocin and higher ACTH concentrations in crated

gilts, and these gilts showed more savaging as well as more activity and responsiveness

towards their piglets. However, the environment did not affect the cortisol concentration

(Jarvis et al., 1998). Ahlstrom (1997) reported a higher responsiveness of crated gilts to their

piglets during early stages of farrowing, but a higher probability to savage their piglets. Sows

in crates without nest materials have been reported to be less responsive to piglet screams one

to three days postpartum (Thodberg et al., 2002a) and vocalise less to piglets on day 1

postpartum in comparison to sows in pens with nest materials (Cronin et al., 1996). On the

other hand, Damm et al. (2002) found no effect of the housing environment on the timing of

termination of nest-building behaviour during parturition or the course of parturition in gilts.

3.2. Housing in pens

The first study on nest-building behaviour in sows in pens was done by Buß (1972). The

phases of nest-building were found to be similar to wild boars (Gundlach, 1968), but

restricted by the provision of space and nesting material. In comparison to wild sows, sows

housed in pens lack orientation, endurance and purposive directness within their instinctive

acts. Explicit exploration behaviour could not be performed and the possibility for digging the

hole was not given; therefore these elements were described as ‘degraded behaviour’ because

of the lack of exogenous stimuli (Buß, 1972).On the contrary, all observed sows showed an

overemphasis in padding out the nest with the straw provided and an exaggerated moving of

straw to cover their body (Buß, 1972). In contrast to Hafez et al. (1962), Buß (1972) did not

observe the sows cleaning the nest.

Sows housed in pens with straw perform more nest-building behaviour than pigs housed in

pens with straw removed (Burne et al., 2000). Sows turn and walk more frequently during 24

hours before farrowing in pens compared to the restricted possible activities in farrowing

crates (Hartsock and Barczewski, 1997). Furthermore, Thodberg et al. (2002b) found more

elaborated nest-building behaviour in ‘get-away-pens’ in comparison to crates and the pre-

partum rooting period started significantly sooner with a longer duration. ‘Nesting-like’

behaviour occurred more frequently in penned than in crated sows (Cronin et al., 1994).

Andersen et al. (2005) described significantly more nest-building activity of sows in pens that

13

had not crushed one single piglet within the first 4 days. Herskin et al. (1998) showed that

provision of nest material to loose-housed sows increased the response to piglet screams one

to three days postpartum. The provision of space, even without straw, encourages the

performance of maternal behaviour during parturition (Jarvis et al. 2004). Against this

background, several attempts to develop alternative farrowing accommodation have been

made. Although there are several alternative farrowing pens, most of the recent research has

been carried out in the ‘Schmid’ or the ‘Werribee farrowing pens’.

Schmid constructed a farrowing pen isolating the sow from other pigs while allowing nest-

building behaviour (Schmid, 1991a; Schmid, 1991b). Under Swiss production circumstances,

piglet mortality in these pens is comparable to that of farrowing crates (Schmid, 1991a; 1992;

1993). In these so-called ‘Schmid pens’ the duration of nest-building is with 8 h shorter than

that in crates with 10.5 h (Damm et al., 2003). Even if the whole period is shorter, sows

perform a greater variety of behaviour including more pawing, nodding, collecting, depositing

and packing (Damm et al., 2003). Another attempt to offer more possibilities for the

expression of nest-building behaviour is the ‘Werribee farrowing pen’ (WFP) (Cronin et al.,

1996). This pen is twice as large as a usual crate and consists of two compartments, a 'nest'

and a 'non-nest' area. The width of these pens affects nest-building behaviour, and an

appropriately wide WFP is recommended (Cronin et al., 1998).

4. Discussion: consequences for modern sow management

As a major part of reproduction, the sow’s pre-farrowing behaviour is strongly associated

with piglet survival because it affects parturition (Heckt et al., 1988; McGlone et al., 1996;

Cronin et al., 1993). Explicit nest-building behaviour can clearly be classified as a

behavioural need for the pre-partum sow. It is a natural adaptation and even domesticated

sows are highly motivated to perform this behaviour pattern. Allowing the sow to perform

nest-building, or at least some elements of it, leads to better health and welfare of both the

sow and the piglets (Algers, 1994). For instance, increased litter sizes were reported to be

positively correlated with more nest-building behaviour (Pedersen et al., 2006). Additionally,

a higher responsiveness to piglet distress calls and a lower mortality rate in piglets until

weaning is documented in sows with better nest-building performance (Cronin and van

Amerongen, 1991). When the opportunity for nest-building is given, the duration of sucking

periods is increased and the number of sucking periods terminated by the sow is decreased

(Herskin et al., 1998). Therefore, the possibility to perform nest-building behaviour should be

offered to all sows in modern management systems. For this possibility, space and the

14

provision of adequate nest-building material are two relevant pre-requisites. Under

confinement, activities that need space like standing or walking can hardly be realized.

Denying sows space and material at the time of strong nest-building motivation is associated

with negative consequences like reduced piglet survival or savaging of piglets (Hötzel et al.,

2005) and results in physiological stress in the sow (Lawrence et al. 1994). With the

implementation of the EU Directive 2001/88/EC, this stress might even have increased

because all sows have to be loose-housed during the majority of gestation and the subsequent

confinement can be a radical change (Boyle et al., 2000). The effects of stress on reproduction

are a matter of scientific discussion. While some authors claim that sows are resistant to the

effects of single or repeated stressors (Turner et al., 2002; Turner et al., 2005), more

commonly it is expected that in pigs experiencing stress, reproduction is negatively affected

(Varley and Stedmann, 1994; von Borell, 1995; Einarsson et al., 1996). In this way, a

prolonged duration of the farrowing period after restricted nest-building is either caused

directly by the less optimal conditions for nest-building or indirectly by the subsequent stress

(Vestergaard and Hansen, 1984). The restraint-stillbirth hypothesis, first established by Baxter

and Petherick (1980), claimed that the stress caused by the restriction of normal pre-farrowing

behaviour in crates induces changes in the endocrine system leading to delayed births and

raised stillbirth. On the contrary, Fraser et al. (1997) hypothesised that stimulating the sows’

pre-farrowing activity by pen-mates or human activity results in a lower stillbirth rate and

suggested therefore a positive influence of stress towards the sows.

In pens and farrowing huts, the design can improve maternal behaviour and increase the

sows’ welfare, which is proposed to lead to a better survival and growth of the piglets (Algers,

1994; Damm et al., 2003). From a holistic point of view, ranking of the motivational effects

of internal and external factors of nest-building behaviour is pointless (Jensen and Toates,

1993), but more moves to adapt the present farrowing systems to these behavioural needs are

required. Farrowing accommodation restraining the sow’s movements has repeatedly been

shown to improve piglet survival (Edwards and Fraser, 1997), but for both economical and

ethical reasons these systems require reconsideration (Edwards, 2002). Alternative housings

systems resulted in similar piglet mortality rates compared to conventional systems (Weber et

al., 2007; Wechsler and Weber, 2007), but the number of crushed piglets was significantly

higher in pens with loosed housed sows (Weber et al., 2007). In loose-farrowing systems,

piglet’s mortality by crushing can be further reduced by a careful selection of environments

and sows showing a genetic determination of positive maternal behaviour (Johnson et al.,

2007).

15

Furthermore, not only space, but the use of nest-building material is restricted in confinement.

This restriction results in the sow’s inability to get external stimuli for the performance of

nest-building behaviour. As shown, this behaviour is influenced both by internal and external

stimuli (Blackshaw, 1983; Jensen, 1988a; Jensen, 1993; Boulton et al., 1997; Burne et al.,

1999; Thodeberg et al., 1999). However, mainly external stimuli are crucial to express

satisfactory nest-building. The act of nest-building alone is more important than the provision

of a nest (Widowski and Curtis 1990). When pre-constructed nests are offered, the sows still

show nest-building behaviour (Arey et al., 1991). In crates, sawdust bedding triggers a more

active nesting-like ‘behaviour’ before farrowing, but once farrowing has started, sows are

more passive (Cronin et al., 1993). This decreases the risk of crushing piglets during

farrowing (Thodberg et al., 1999). Furthermore, these sows had a shorter duration of

parturition (Cronin et al., 1994), and more piglets born alive, compared to sows that do not

receive sawdust bedding (Cronin et al., 1993). McGlone et al. (1996) found that sows housed

in farrowing crates with access to a cloth tassel that could be manipulated during the pre-

farrowing period, tend to have a reduced incidence of stillbirth. Hötzel et al. (2005) noticed

that providing confined sows with enough space and material decreased some of the negative

effects of confinement, but did not eliminate them completely.

In the last years, legislation has assessed the welfare benefits of loose-farrowing systems and

the implicated positive effects. The intention of several European Commission Directives,

such as Directive 2001/88/EC regarding loose-housing, or Directive 2001/93/EC regarding

rooting material, is to improve the welfare of pigs, but the sows’ maternal behaviour has not

yet been adequately considered in the legislation. In this regard, not only the piglets’ survival,

health and welfare have to be taken into account, but also the sows’ health and welfare,

including the reproduction performance.

An enriched environment in crates and a greater space for movement are first steps towards

the reconsideration and integration of behavioural maternal needs in modern pig management.

Therefore, following actions should be put into practice:

(i) in sow management: even though crates might be with no alternative in the following

years, all chances to integrate the sows’ behavioural needs should be taken. Under

consideration of management, economic, health and hygiene factors, suitable material and

space for nest-building-performance should be provided in the pre-partal period.

16

(ii) in research: alternative pens and nest-building material should be tested in detail with

regard to practicability, application and effects on sows and piglets. Individual characteristics

of single sows like maternal behaviour should be examined with respect to their genetic

determination in order to breed sows better adapted to more open farrowing surroundings

(Grandinson et al., 2003, 2005).

(iii) in legislation: results from research should be implemented into consistent EU-

Regulations, considering space and material requirements in enriched environments.

Practice, research and legislation together should concentrate on management tools to realise

an improvement of the sow’s need for nest-building performance, not only in order to

optimise the sows’ health and welfare, but also for the following positive effects on consumer

perception and price building.

5. Conclusion

A better understanding of behaviour patterns in general and farrowing behaviour, including

nest-building in sows, is essential for an economically successful pig production. Compared

to their ancestor, the wild boar, domestic sows perform nest-building as part of maternal

behaviour in a nearly unmodified way. However, the pre-parturient behaviour is considerably

affected by the husbandry system and is only shown to its full extent when environmental

circumstances allow it. If the sow cannot follow her natural behavioural need, for instance

when no material is available, she redirects her nest-building behaviour towards the pen or

crate equipment. This results in stereotypes and stress, followed by a reduced reproduction

performance. With regard to animal health and welfare, loose farrowing systems provide a

good alternative while maintaining a high production performance. As long as these systems

are not implemented, the farmers should provide at least suitable nest-building material like

straw. Concluding, further research should evaluate and promote alternative enriched systems

in order to support the economic use of these systems for the farmers.

Acknowledgement

The manuscript has benefited from the critical and helpful comments of an anonymous

reviewer.

17

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26

27

CHAPTER TWO

Characterisation of sows’ postures and posture changes with regard to crushing piglets

Diane Wischner1, Nicole Kemper1, Eckhard Stamer2, Barbara Hellbruegge1,

Ulrich Presuhn3 and Joachim Krieter1

1Institute of Animal Breeding and Husbandry, Christian-Albrechts-University, 24098 Kiel,

Germany 2 TiDa Tier und Daten GmbH, Bosser Strasse 4c, 24259 Westensee/Brux, Germany

3 farm concepts GmbH & Co. KG, Heidmühlender Strasse/Moorhof, 23812 Wahlstedt,

Germany

Published in Applied Animal Behaviour Science, 2009, 119: 49-55

28

Abstract

The aim of this study was to analyse different behavioural traits of sows to describe posture

changes and to determine the influences of these traits on piglet losses. The behaviour of 386

German Landrace sows (with 438 pure-bred litters) was videotaped continuously starting 12

hours prepartum until 48 hours post partum in a nucleus herd for one year. From this

population, 40 sows were randomly sampled with a block data design. Twenty sows which

crushed one or more than one piglet (C-sows) were compared to 20 sows which crushed no

piglets (NC-sows). The postural behavioural traits were analysed according to duration,

manner and frequencies of positions (‘descending from standing to lying’ behaviour,

‘standing-up’ behaviour) as well as the time taken for various posture changes. Each

respective trait was calculated according to the difference between NC-sows and C-sows.

Results revealed that prepartum, NC-sows were more restless; primiparous ones in particular

performed more posture changes (P = 0.109) and tended to ‘stand up’ more often (P < 0.01).

Additionally, they ‘stood’ more often (P < 0.05) and performed ‘nest-building’ behaviour

with higher frequencies, particularly in the seventh (P < 0.01) and sixth hours (P < 0.1) before

parturition and with longer durations than C-sows. Post partum, NC-sows performed no

different activities in movement pattern compared to C-sows. However, compared to

primiparous NC-sows, primiparous C-sows showed more ‘rolling’ movements (P < 0.01). C-

sows preferred ‘ventral recumbency’ within ‘rolling’ movements (P < 0.05) and as the final

position of ‘descending from standing to lying’ (P < 0.1). Furthermore, the bouts of ‘sitting’

behaviour of C-sows were much longer than of NC-sows, especially multiparous ones (P <

0.01). NC-sows performed ‘lateral recumbency’ much longer and also more often as the final

position of ‘descending from standing to lying’ (P < 0.01). These results suggested that

posture patterns of NC-sows and C-sows are different, especially ‘nest-building’ behaviour

prepartum and ‘ventral-‘ or ‘lateral recumbence’ post partum, indicating a possible use to

characterise the maternal abilities of sows in minimising piglet crushing.

Keywords

Crushing; Posture changes; Farrowing; Maternal ability; Pig

1. Introduction

One major aim of pig production is the decrease in piglet losses to improve the economic

success characterised by high numbers of weaned piglets per sow and year. The number of

piglets weaned is determined mainly by piglet losses in the suckling period. In commercial

29

pig production, piglet mortality vary between 10 and 20 % (Alonso-Spilsbury et al., 2007),

presenting a considerable welfare and production problem. The majority of piglet deaths are

observed in the first two days of lactation across several types of housing (English and Smith,

1975; Svendsen et al., 1986; Barnett et al., 2001; Hellbrügge et al., 2008a). Particularly with

regard to loose-housed sows, a high number of crushed piglets are observed (Wechsler and

Hegglin, 1997). Thus, the farrowing crate was introduced in the 1960s to decrease piglet

mortality, especially the crushing of piglets by the sow, to make routine sow and piglet

management easier for the stockperson, and to allow a greater number of animals to be kept

per unit (Fraser and Broom, 1990; Edwards, 2002). However, 47.4% of suckling losses are

related to crushing (Kunz and Ernst, 1987), especially within the first 24 hours post partum

(Marchant et al., 2001).

In addition to the traditional traits of selection to improve litter size, such as piglets born alive

or birth weight, the maternal ability of sows is becoming more and more important. Increased

litter size puts higher demands on the ability of sows to raise large litters (Grandinson, 2005).

Maternal ability, including maternal behaviour, can be described by different maternal traits

(Wallenbeck et al., 2008). Large individual differences are seen in the behavioural patterns

within sows, especially in posture changes (Marchant et al., 2000; Thodberg et al., 2002).

Moreover, the frequency of posture changes and the quality of ‘descending from standing to

lying’ movements have previously been used as indicators of maternal protectiveness

(Wechsler and Hegglin, 1997). There are several different major body movements of sows

which represent danger of crushing for the piglets (e.g. stand-lie, sit-lie, lie-sit) (Weary et al.,

1996a). Wechsler and Hegglin (1997) described sows which are generally more careful than

others when changing positions. Algers (1994) showed that sows performing better ‘nest-

building’ and showing better responses to different stimuli by the piglets performed

significantly better in a farrowing hut. Thus, pre-farrowing behaviour is very important for

piglet survival (Heckt et al., 1988). Therefore, the understanding of sows’ behaviour is

essential to support management possibilities in order to optimise the piglets’ chances of

survival. Finally, improved maternal behaviour increases the welfare of piglets and sows

(Grandinson, 2005).

The purpose of this study was to compare the behaviour of sows which did not crush any

piglet with sows that crushed one or more than one piglet in order to identify the possible key

features of sows’ behavioural patterns influencing the risk of crushing.

30

2. Material and methods

2.1. Animals and environment

Data were recorded in a nucleus herd of the German breeding company ‘Hülsenberger

Zuchtschweine’ from January to December 2004. Data of 386 Landrace sows with 438 pure-

bred litters were available. During lactation the sows were housed in conventional farrowing

crates with dimension of 2.74 m x 1.75 m. The sows were fixed in diagonally ordered

farrowing crates. No nesting material was provided to the sows. Twenty sows were crated per

farrowing house, ordered by the calculated farrowing date. In the farrowing crate, underfloor

heating and heat lamps were provided. The piglet nest area was located laterally in front of the

sow’s head. Sows were managed in a one-week rhythm with a 21-day lactation period. The

sows were fed once per day, and from the second day post partum twice per day. During the

whole study time, no medication was administered.

2.2. Sampling methods

Videotapes were recorded using the HeiTel Player software program (HeiTel Digital Video

GmbH, Kiel). Sixteen sows within one farrowing batch were filmed simultaneously by eight

cameras. In this way, the movement patterns (frequency, duration, change of posture) of the

sows were continuously observed from overhead with the period of 12 hours before

parturition up to 48 hours after parturition. Overall, 26,280 hours of behaviour were recorded

on videotapes. Subsequently, the duration (d; seconds) and the frequency (f; number per hour)

of the behavioural traits were analysed by one person by using a self-written database to build

data files for SAS (SAS, 2004).

2.3. Behavioural observations

The recorded single behavioural traits are given in Table 1.

Table 1: Recorded behavioural traits according to videotape analyses (modified by Lou and

Hurnik, 1998)

Trait Definition

Standing Upright body position on extended legs with hooves only in contact

with the floor

Sitting Partly erected on stretched front legs with caudal end of body

contacting the floor

31

Kneeling on front legs Kneeling with both carpal joints on the floor

Sternal recumbency Lying on abdomen with front and hind legs folded under the body

Ventral recumbency Lying on abdomen with front legs folded under the body and

visible hind legs

Lateral recumbency Lying on either side with all four legs visible

Nest-building Continuously oronasal contact with floor and head movements

Rolling All occurrences of postural changes between lying on one side to

lying on the other side (side-swapping)

‘Rolling’ movements were analysed in different positions from the end of the starting position

to the beginning of the next position. The following ‘rolling’ movements were analysed: LL

(lateral-lateral), VV (ventral-ventral), LV (lateral-ventral), VL (ventral-lateral). For example,

the trait ‘lateral-lateral (LL)’ explained the duration of swapping from ‘lateral recumbent’ on

the one side to ‘lateral recumbent’ on the other side. Additionally, the ‘rolling’ movements

towards and away from the piglet nest were analysed.

‘Recumbency’ was defined as the sum of frequency of ‘sternal-‘, ‘ventral-‘ and ‘lateral

recumbent’ positions. ‘Movement’ behaviour was defined as the sum of the frequency of

‘standing’, ‘sitting’, ‘kneeling on front legs’ and ‘recumbency’.

In the next step, the described behavioural traits were differentiated into 22 additional traits to

analyse durations of different behavioural patterns with ‘standing-up’ or ‘descending from

standing to lying’ in a special manner (Table 2).

Table 2: Differentiated behavioural traits for recorded behavioural patterns (ascending

behaviour indicated in italics, descending behaviour in normal font)

Behavioural trait Following behavioural trait

Standing Sitting

Kneeling on front legs

Ventral recumbency (right side + left side)

Lateral recumbency (right side + left side)

Sitting Standing

Kneeling on front legs

Ventral recumbency (right side + left side)

Lateral recumbency (right side + left side)

32

Kneeling on front legs Standing

Sitting

Sternal recumbency

Ventral recumbency (right side + left side)

Lateral recumbency (right side + left side)

Sternal recumbency Kneeling on front legs

Ventral recumbency (right side + left side)

Lateral recumbency (right side + left side)

Ventral recumbency (right side + left side) Kneeling on front legs

Sternal recumbency

Lateral recumbency (right side + left side)

Lateral recumbency (right side + left side) Kneeling on front legs

Sternal recumbency

Ventral recumbency (right side + left side)

For instance, the trait ‘standing-sitting’ explained the duration of postural change from

‘standing’ to ‘sitting’ posture.

2.4. Sample of animals and statistical analysis

Lehner (1992) proposed ‘sampling of all occurrences’ as the method of choice to generate

accurate frequency and duration data. For our study, videotapes, each of 60 hours length, from

438 litters were available. To realise this examination, a block data design of 40 animals was

chosen. Twenty sows without any crushed piglets (NC-sows) were randomly sampled by

using uniform distribution procedure (SAS, 2004).

Table 3: Means, standard deviations (s.d.), minimum (min.), maximum (max.) and statistical

differences (P-values) of the reproductive traits of NC-sows and C-sows (n = 40)

Traits Means±s.d. min. -max. P-values

NC C NC C

Total number born per litter 9.8±2.67 11.25±2.57 4-15 7-16 0.0068

Number born alive per litter 9.2±2.73 10.15±2.28 4-13 6-14 0.0239

Number stillborn per litter 0.6±1.50 1.05±3.24 0-4 0-6 0.0171

33

Sows with one or more crushed piglets within the first 48 hours after parturition (C-sows)

were selected conforming the NC-sow group (Table 3), considering the matching criteria

number of piglets born alive, parity and farrowing date (season). Significance of differences

between the means of NC- and C-sows was tested by using the TTEST and NPAR1WAY

procedure of SAS (2004).

Piglets’ deaths were defined visually on farm, and crushing was determined in combination

with video analysis. Crushing was characterised as ‘no movement of trapped piglet after a

change in the sow’s posture’, as described by Vieuille et al. (2003). The selected sows were

healthy, which was determined by body temperature (max. 39.5° C) within three days after

parturition and evaluation of the exterior correctness without extreme deviations determined

by a linear scoring system before lactation, as described previously (Hellbrügge, 2007).

According to the matching criteria, a block data design was created arranging NC-sows and

C-sows in pairs. The average parity number of pairs was 2.35 and ranged from 12 pairs as

gilts and eight pairs from the third to the tenth parity. Five pairs had their farrowing date in

March or April, ten pairs in May and June, and the rest in August and September.

Except for higher numbers of piglets born alive, C-sows did not differ in comparison to NC-

sows. All litters were adjusted by cross-fostering post partum, depending on the litter sizes per

farrowing group. The performance of sows and further data on the piglets was represented in

detail by Hellbrügge et al. (2008a). The crushing mortality on the farm was 12.4%, with 8.8%

within the first three days (Hellbrügge et al., 2008a).

In total, 20 C-sows were analysed which crushed 27 piglets within the first 48 hours post

partum. Within the first 24 hours post partum, 70% of these piglets were crushed. Two-thirds

of them were male with an average body weight of 1.28 kg. The observed crushing was

performed in 63% by the hindquarter, in 32% by the shoulder and in 5% by the back. Most

piglets were crushed while the sow performed ‘descending from standing to lying’ (63%),

22% were crushed during ‘rolling’ behaviour and only 15% piglets were crushed while the

sow ‘stood up’.

Significance of differences between NC-sows and C-sows were analysed with a linear model

using the MIXED procedure of the SAS statistical software package (SAS, 2004). The

behavioural traits and the associated residuals were not normally distributed. For this reason,

normally distributed residuals as a pre-condition of linear models could be realized by using

differences. Differences in independent random variables will be approximately normally

distributed (central limit theorem). Thus, for every behavioural trait, the difference between

34

the behavioural traits of C-sows was subtracted from the respective behavioural trait of NC-

sows.

The model included the fixed effects of parity (‘first parity’ and ‘higher parities’), season for

farrowing (‘March to April’, ‘May to June’ and ‘August to September’), and time interval to

the beginning of farrowing, which was calculated in hours beginning with ‘12 h before

farrowing’ and ending with ‘48 h after farrowing’. The time intervals before farrowing

(prepartum) and beginning with farrowing (peri-/ post partum) were analysed separately.

Model:

yijkl = µ + Pi + Sj + Tk + eijkl

with:

yijkl = difference between NC-sow and C-sow (pair) of the respective traits

µ = overall mean

Pi = fixed effect of the i-th parity class (i = 1, 2)

Sj = fixed effect of the j-th season class (j = 1, 2, 3)

Tk = fixed effect of the k-th time (k = -12, …, -1 hour and k = 0, …, 48 hour respectively)

eijkl = residual effect

The differences are multiple measurements within sow pair over a period of time (12 h before

or 48 h after farrowing). For such datasets it is assumed that the repeated measures are not

independent and thus autocorrelated (Littell et al., 2006). Therefore, it was necessary to use

applicable error covariance structures for valid statistical inferences. Different structures were

compared for their ability to fit the model using the likelihood ratio test and criteria of Akaike

(1973) and Schwarz (1978). Generally, measurements closer together have higher correlations

than measurements with longer time gaps between them (Littell et al., 2006). Here, the first-

order autoregressive model, AR(1), was chosen with Covariance Parameter Estimates

between 0.85 and 0.20. The significance of fixed effects was tested by the F-test implemented

in the MIXED procedure in SAS (SAS, 2004). With regard to the pre-conditions for linear

models, homogeneity of variance was checked by plots of the standardised residuals against

the predicted values. For instance, the plot of standardised residuals against the predicted

values of the behaviour trait ‘standing frequency before farrowing’ showed the desired

residual bond (Figure 1).

35

-4

-3

-2

-1

0

1

2

3

4

predicted standing frequency

stan

dard

ised

res

idua

ls

Figure 1: Plot of standardised residuals against the predicted ‘standing’ frequency before

farrowing

3. Results

3.1. Prepartum

The NC-sows ‘moved’ more often than the C-sows, except in the fifth and fourth hours before

farrowing. Primiparous NC-sows in particular were more restless and performed on average

5.5 times more posture changes than C-sows (P > 0.05). Before farrowing, increased activity

of NC-sows, especially primiparous ones, was confirmed by ‘standing’ behaviour. NC-sows

‘stood’ more often than C-sows (P < 0.05). Furthermore, increased activity of primiparous

NC-sows in comparison with C-sows was confirmed by ‘nest-building’ behaviour. Key

aspects of increased activity, characterised by the line of means, were observed in the seventh

and fourth hours before farrowing (Figure 2).

36

-60

0

60

120

180

240

300

360

420

480

-12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1

hours prepartum

seco

nds

/ hou

r (L

SM

and

S.E

.)

-60

60

180

300

420

540

660

780

seco

nds

/ hou

r (m

ean)

differences (NC-C) in duration of 'nest-building' (LSM and S.E.)

duration of 'nest-building' (mean)

Figure 2: Differences (NC-C) in duration of ‘nest-building’ (LSM and S.E.) related to

crushing and duration of ‘nest-building’ (mean) (n = 2,766)

NC-sows performed this behavioural pattern on average 3.5 times more often and for longer

periods (LSM 127 seconds per hour) than C-sows except in the ninth and second hours before

farrowing.

The significance of the fixed effect time was found for the trait ‘nest-building’ behaviour. In

the seventh and sixth hours before farrowing there were significant differences in frequency

and duration of the LSM of ‘nest-building’ and more total activity of NC-sows was observed.

3.2. Post partum

From the beginning of parturition, ‘standing’ behaviour had significant differences in

frequency and duration (LSM 94 seconds, P < 0.05) in primiparous NC-sows compared to

primiparous C-sows. However, C-sows, especially multiparous ones, performed much longer

bouts of ‘sitting’ (LSM 64 seconds) than multiparous NC-sows (P < 0.01). The means of

‘rolling’ frequency showed an increase after nearly one day, as indicated especially for C-

sows, and equalised for all sows after this peak (Figure 3).

37

-1

-0.5

0

0.5

1

1.5

2

2.5

1 7 13 19 25 31 37 43

hours peri-/ post partum

freq

uenc

y / h

our

(LS

M)

-4

-2

0

2

4

6

freq

uenc

y / h

our

(mea

n)

first parity- differences (NC-C) in frequency of 'rolling' behaviour (LSM)differences (NC-C) in frequency of 'rolling' behaviour (LSM)frequency of 'rolling' behaviour (mean)

Figure 3: Differences (NC-C) in frequency of ‘rolling’ behaviour (LSM) related to crushing,

additionally only for first parity and frequency of ‘rolling’ behaviour (mean)

(n = 131)

In comparison to C-sows, NC-sows showed tendencies for fewer and shorter ‘rolling’

movements. Particularly primiparous C-sows ‘rolled’ more often (P < 0.01), and needed 4

seconds longer than primiparous NC-sows to swap from one side to the other (P < 0.05).

Furthermore, there were significant differences in side-swapping: from ‘ventral recumbency’

to ‘ventral recumbency’ (VV), primiparous C-sows performed ‘rolling’ movements more

often (P < 0.01) than primiparous NC-sows and with longer durations (P < 0.05). In contrast,

multiparous NC-sows took a longer duration to swap sides from VV than multiparous C-sows

(P < 0.05). From ‘lateral recumbency’ to ‘ventral recumbency’ (LV), primiparous C-sows

showed ‘rolling’ movements more often than primiparous NC-sows (P < 0.05). Any other

‘rolling’ movements did not differ between NC-sows and C-sows. Additionally, tendencies of

‘rolling’ movements towards the piglet nest or away from the piglet nest could not be

observed in NC-sows and C-sows.

Primiparous NC-sows showed a significant difference in the frequency of ‘standing-up’

behaviour in the form of ‘kneeling-sitting-standing’ compared to primiparous C-sows (P <

0.01). NC-sows were much more active.

38

Besides the differences in duration of ‘descending from standing to lying’, starting from

‘sitting’ position, primiparous C-sows took five seconds (LSM) longer than primiparous NC-

sows. The primiparous C-sows ‘lay down’ more often than primiparous NC-sows (P < 0.1)

with the final position of ‘ventral recumbency’. The primiparous NC-sows preferred the

‘lateral recumbency’ final position (P < 0.01).

C-sows performed a significantly longer duration of ‘ventral recumbency’ (LSM) than NC-

sows several hours after parturition, especially within the first 15 hours post partum (Figure

4). The line of means describes an oppositional trend with shorter durations within the first 12

hours in ‘ventral recumbency’ (Figure 4).

-11

-6

-1

4

9

14

19

24

29

34

1 7 13 19 25 31 37 43

hours peri-/ post partum

min

utes

/ ho

ur (

LS

M a

nd

S.E

.)

-15

-5

5

15

25

min

utes

/ ho

ur (

mea

n)

differences (NC-C) in duration of 'ventral recumbency' (LSM and S.E.)duration of 'ventral recumbency' (mean)

Figure 4: Differences (NC-C) in duration of ‘ventral recumbency’ (LSM and S.E.) related to

crushing and duration of ‘ventral recumbency’ (mean) (n = 2,335)

In contrast, NC-sows showed significantly longer durations of ‘lateral recumbency’ at

different times than C-sows. Furthermore, NC-sows performed longer and more often

‘descending from standing to lying’ with the ‘lateral recumbency’ final position than C-sows.

4. Discussion

Studies by Haskell and Hutson (1996) and Damm et al. (2003) showed that sows perform

increased activity behaviour in terms of postural changes during the pre-farrowing period in

different kinds of housing. In the present study, sows housed in crates, particularly

39

primiparous NC-sows, performed an activity expressed in increased ‘standing’ behaviour and

decreased ‘descending from standing to lying’ prepartum. Jensen (1989) observed in loose-

housed sows a peak of activity in the period 16 to 8 hours of pre-farrowing, especially

‘standing’, in which ‘nest-building’ behaviour typically occurred. At this time peak, the

behaviour of crated NC-sows and C-sows differed significantly in the present study, as well.

Especially primiparous NC-sows ‘stood’ more often than primiparous C-sows. Additionally,

in this activity NC-sows performed significantly more often and in longer bouts ‘nest-

building’ behaviour pattern equal to their wild ancestors, even in crates without any available

‘nest-building’ material. The onset and performance of ‘nest-building’ is both stimulated

internally via hormones, for instance prolactin, and externally via feedback from the

environment. With this environmental influence, the possibilities to perform ‘nest-building’

can be restricted to different extents in commercially farmed pigs, but elements of this innate

behaviour are always shown (Wischner et al. 2009). Due to the lack of material, ‘nest-

building’ behaviour was performed only against the floor and fittings of their crates. Damm et

al. (2003) assessed that the crate environment restricted the sows either indirectly due to a

feedback mechanism or directly by preventing physical activity, so that more fragmented

‘nest-building’ behaviour was observed in crates than in pens. However, in this study, sows in

crates did perform ‘nest-building’ behaviour, and differences between NC-sows and C-sows

were identified additionally. NC-sows performed longer ‘nest-building’ behaviour more

often. In another study, non-crusher sows showed significantly more ‘nest-building’ activities

before the onset of farrowing than crushers (Andersen et al., 2005). However, Pedersen et al.

(2006) described that the passivity of sows, represented by low ‘nest-building’ activity, was

followed by low post partum motivation for behavioural patterns and resulted therefore in

safer postural changes for the piglets. Even though comparison between different studies is

limited because of differences in the observed parameters and housing conditions, these

results could not be confirmed in this study. Lower ‘nest-building’ activity as shown in C-

sows, was followed by higher piglet mortality.

The reasons for crushing are difficult to analyse, since behaviour patterns which sows and

piglets perform to avoid crushing need to be considered not only in their occurrence, but also

in the way they are performed (Pedersen et al., 2006). In this respect, the motivation for

‘careful’ behaviour has to be regarded. In this study, further detailed observations to possible

piglet responses associated with vocalisation from the dam could not be determined, because

there was no audio information on the time-lapsed video records.

40

Another cause for crushing is related to litter size. Johnson et al. (2007) showed that crusher

sows had more piglets born per litter than non-crusher sows. One biological reason for fatal

trampling and crushing may be that it represents an alternative way of reducing maternal

investment, especially in large litters (Andersen et al., 2005). In a similar way, the Parental

Investment Theory (Evans, 1990) claims that any parental investment in the offspring lowers

the parent’s ability to invest in future piglets, and is therefore decreased with higher parities

(Held et al., 2006).

However, in larger litters, piglets’ body weights vary, and therefore, the risk of crushing is

increased for the smaller ones. On the contrary, breeds with large litters, for instance Meishan

sows, show lower losses due to crushing, because they are more vigilant and aware of the

piglets’ location (Hohenshell et al., 1996).

Our results showed that C-sows preferred the ‘ventral recumbency’ for a longer duration and

as final position of ‘descending from standing to lying’. This lying position does not allow the

piglets’ full access to teats, as in ‘lateral recumbency’ (Damm et al., 2000). Therefore it has

been reported that optimum maternal behaviour is characterised by passivity and ‘lateral

lying’ (Jarvis et al., 1999; Hellbrügge et al., 2008b). Thodberg et al. (1999) found that after

the initial, more active period, sows generally lie in ‘lateral recumbency’. Cronin and Smith

(1992) observed a longer duration of lying in ‘lateral recumbency’ from 65% to 95% of total

time the first day after farrowing. In our study, NC-sows performed in the first day after

parturition significant longer bouts of ‘lateral recumbency’, which permitted the piglets to

find and remain near the udder to consume colostrum.

The manner of ‘descending from standing to lying’ had an essential influence on the crushing

risk in piglets (Vieuille et al., 2003). In the present study, only the final lying position after

‘descending from standing to lying’ differed between the NC-sows and C-sows. C-sows

preferred more often ‘ventral recumbency’ after ‘sitting’ and ‘kneeling on front legs’, while

NC-sows preferred ‘lateral recumbency’ after ‘sitting’ and ‘kneeling on front legs’. Consistent

with Marchant et al. (2001), no association was detected between times taken to lie down and

crushing. However, Damm et al. (2005) described the risk of crushing to be highest during

fast and uncontrolled body descending, because piglets had less time to escape or to vocalize

loudly. In agreement with this statement, in our study 70% of the piglets were crushed while

the sow performed ‘descending from standing to lying’. The manners in which the sow ‘lay

down’ were not relevant for the piglets’ deaths due to crushing by the sow.

Generally, the risk of crushed piglets rises when the piglets have consumed little or no

colostrum, especially when the sow performs many postural changes (Weary et al., 1996b). In

41

particular, ‘rolling’ behaviour was shown more often and in longer bouts by primiparous C-

sows in comparison with primiparous NC-sows. In our study, 22% of all crushed piglets were

related to ‘rolling’ behaviour. C-sows swapped sides from ‘lateral-‘ or ‘ventral recumbency’

to ‘ventral recumbency’ more often than NC-sows. But in opposition to Damm et al. (2005),

slower ‘rolling’ movements of primiparous C-sows were identified as risky behaviour. In the

contrary, in multiparous NC-sows, slower ‘rolling’ movements decreased the risk for the

piglets. This is incompatible with Svendsen et al. (1986), showing an increase of the crushing

risk for sows in higher parities. This is most probably related to the gain in body size,

resulting in a reduced agility and phlegmatic behaviour in general (Weary et al., 1998). The

effects of the confinement by crates become more apparent in heavier multiparous sows that

are slowed down in their ‘rolling’ movements. On the contrary, primiparous sows are still

able to perform ‘rolling’ movements in a different manner and frequency due to their smaller

size.

Usually, ‘sitting’ was an unavoidable stage during postural change from ‘lying’ to ‘standing’

whereas it was not necessary vice-versa from ‘standing’ to ‘lying’. C-sows performed a

significant higher ‘sitting’ duration than NC-sows after parturition. After farrowing, sows in a

‘sitting’ posture could not stay close to their piglets. But this proximity is necessary to provide

warmth and access to the udder to obtain adequate milk intake (Weary et al., 1996a). The

most dangerous body movements for the piglets occurred when the sow ‘lay down’ in an

uncontrolled manner, even from ‘sitting’ to ‘lying’ (Edwards et al., 1986). In the present

study, only 11% of piglets were crushed by ‘descending from standing to lying’, starting with

a ‘sitting’ position. By ‘descending from standing to lying’, 63% of the piglets were crushed.

Despite this high percentage, no differences between NC-sows and C-sows in their

‘descending from standing to lying’ performance were observed. This might indicate the

involvement of traits that were not assessed in our study, for instance a better responsiveness

to their piglets or a different vocalisation in NC-sows.

5. Conclusion

A better understanding of behavioural patterns in farrowing behaviour is essential for

increasing the proportion of piglets weaned and thus improving economic success in pig

production. A significantly longer duration and higher frequency of standing posture, and a

significant higher frequency in standing-up and lying-down combinations was performed by

NC-sows in our study. This higher activity in NC-sows might express a better responsiveness

towards their piglets. Further research with comprehensive sampling should concentrate on

42

traits with significant differences which have to be verified, indicating a possible use in

selection of sows with optimal maternal abilities.

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47

CHAPTER THREE

Pre-lying behaviour patterns in confined sows and their effects on crushing of piglets

Diane Wischner1, Nicole Kemper1, Eckhard Stamer2, Barbara Hellbruegge1,

Ulrich Presuhn3 and Joachim Krieter1

1Institute of Animal Breeding and Husbandry, Christian-Albrechts-University, 24098 Kiel,

Germany 2 TiDa Tier und Daten GmbH, Bosser Strasse 4c, 24259 Westensee/Brux, Germany

3 farm concepts GmbH & Co. KG, Heidmühlender Strasse/Moorhof, 23812 Wahlstedt,

Germany

Published in Applied Animal Behaviour Science, 2010, 122: 21-27

48

Abstract

In order to determine the influences of different posture patterns of sows on piglet losses, the

present study aimed at the analysis of different elements of pre-lying behaviour peri and post

partum. Over the course of one year, the behaviour of 386 German Landrace sows (with 438

pure-bred litters) in a nucleus herd was videotaped continuously starting 12 hours ante partum

until 48 hours post partum. From these animals, 40 sows were randomly sampled with a

block-data design. Twenty sows which crushed one or more than one piglet (designated as C-

sows) were compared to 20 sows which crushed no piglets (designated as NC-sows). The

analysis covered the frequency, duration and manner of the sows’ pre-lying behaviour.

Combinations with other positions were assessed. The piglets’ resting-activity cycles and

their location regarding the sow were also recorded. The respective behaviour was calculated

according to the differences between NC-sows and C-sows. Results showed that post partum,

NC-sows – in particular primiparous ones – performed ‘sniffing’ as an element of pre-lying

behaviour significantly more often and with longer duration (30 seconds) than primiparous C-

sows. Before ‘kneeling down on their front legs’ and changing into ‘lateral recumbency’, the

primiparous NC-sows ‘sniffed’ more often than the C-sows (P < 0.01). Furthermore, NC-

sows – especially multiparous ones – ‘looked around’ more often, also towards the piglet’s

nest site, before descending from standing to lying by ‘kneeling on front legs’ (P < 0.05).

‘Nosing’, often in combination with ‘looking around’, was significantly more frequent in

primiparous NC-sows than in primiparous C-sows. The duration of the sleeping and activity

behaviour at the mammary gland had a tendency to be longer in the piglets of C-sows than in

those of NC-sows (P < 0.1). Thus, these results indicate that elements of pre-lying behaviour

of NC-sows and C-sows are performed in different ways. Therefore, ‘sniffing’, ‘looking

around’, and ‘nosing’ as components of the pre-lying behaviour represent useful elements to

characterise the maternal responsiveness of sows in relation to the crushing of piglets.

Keywords

Maternal behaviour; Nosing; Posture patterns; Responsiveness; Sniffing

1. Introduction

Good maternal behaviour is the most important pre-condition for high sow productivity.

During domestication, most of the maternal behavioural patterns of sows remain unaltered

(Špinka et al., 2000). However, in modern pig husbandry, increasingly larger litters demand a

greater responsibility of the sows towards their offspring (Grandinson, 2005).

49

This responsibility is of enormous importance, in particular for neonatal piglets. Sows’

behavioural patterns, specifically postural ones, influence the piglets’ behaviour and result in

consequences for milk intake and growth, but also in possible danger due to crushing. The

danger of being crushed is high and prudent maternal responsiveness is urgently required

especially within the first few days when the young piglets have a tendency to sleep directly

next to the sow’s warm mammary glands and their co-ordination is not yet fully developed

(Titterington and Fraser, 1975). The occurrence of crushed piglets is strongly related to

individual differences in the protective behaviour of sows (Wechlser and Hegglin, 1997;

Andersen et al., 2005). The performance of maternal behaviour is strongly influenced by

individual characteristics such as dominance, age, experience and the inter-individual

variability based on genetic differences (Andersen et al., 2005). As shown by Hellbrügge

(2007), the heritability of maternal behaviour during lactation was 0.14, offering a possibility

to include these characteristics in selection programmes.

Responsiveness, attentiveness and protectiveness are substantial pre-requisites for adapting

the sow’s behaviour to attain maximal maternal success. Pre-lying behaviour and the

associated interaction between sow and piglet play an important role in minimising the risk of

crushing (Marchant et al., 1996). In this way, early nose-to-nose contact within the first day

post partum initiates the start of the bonding process between sow and piglet, enabling them

to identify each other (Petersen et al., 1990). This allows the piglet to know which sow to

approach for milk and protection; and the sow is assured that she is investing her resources in

her own offspring (Horrell and Hodgson, 1992).

Due to high mortality rates by crushing within the most critical period of piglets’ survival

during the first two days post partum, most sows today are housed in crates (Barnett et al.,

2001; Johnson et al., 2007). The farrowing crate was designed to reduce piglet losses by

restricting the body movements of the sow and to provide a zone of retreat for the piglets,

especially the neonates (Baxter, 1984). Several studies have shown that behaviour during

parturition is strongly affected by the environment (Pedersen et al., 2003; Jarvis et al., 2004).

Therefore, the behaviour of confined sows may change due to the restriction of the housing

environment (Fraser et al., 2001). However, Heckt et al. (1988) observed very similar

postures and activities for maternal characteristics in different housing systems. Johnson et al.

(2001) did not find any differences between sows in intensive indoor or outdoor production

systems in the time spent by the piglets in direct contact with the sow.

This study analysed pre-lying and piglet-related behaviour in sows which did not crush any

piglet and in sows that crushed one or more than one piglet, respectively. The objective of the

50

1.75

m

2.74 m

H

F + W

C

F + W

C

H

CAM

investigation was to compare pairs of sows with equal production parameters which only

differed in the fact that they did or did not crush piglets.

2. Material and methods

2.1. Animals and environment

Data were recorded from January to December 2004 in a nucleus herd of the ‘Hülsenberger

Zuchtschweine’ breeding company in Austria. Information of 386 Landrace sows with 438

pure-bred litters was available. Sows were housed in diagonally ordered farrowing pens of

homogeneous type with dimension of 2.74 m x 1.75 m during lactation (Figure 1). Crate

dimensions were individually adjusted to the size of each sow. No nesting material was

provided for the sows. Twenty sows were penned per farrowing compartment, ordered by the

calculated farrowing date. In the farrowing pen, underfloor heating and heat lamps were

provided. The piglet nest area was located laterally beside the sow.

Figure 1: Dimensions (m) and floor plan of the accommodation

Key: H = heated area for piglets; F = food bowl; W = water; C = farrowing crate;

CAM = position of the camera

The sows were managed in a one-week rhythm with a 21-day lactation period. They were fed

once per day, and from the second day post partum twice per day. During the whole study

time, no medication was administered.

51

2.2. Sampling methods

The HeiTel Player software program (HeiTel Digital Video GmbH, Kiel) was used to record

videotapes. Eight cameras filmed sixteen sows within one farrowing batch simultaneously.

The movement patterns (frequency, duration, transition of posture) of the sows were

continuously observed from overhead within the period beginning with parturition (first piglet

born) up to 48 hours after parturition. A total of 26,280 hours of video material were

recorded. This data was analysed by one person with regard to the frequency (f; number per

hour) and the duration (d; seconds or minutes) of the behavioural elements, and a self-written

database to build data files for SAS (2005) was used.

2.3. Behavioural observations

The types of behaviour recorded are shown in Table 1. Furthermore, the resting-activity cycle

of the piglets was analysed for duration and frequency. The start and end points for the time

and location of the piglets’ sleeping and activity were recorded (Table 2). The start of

sleeping and the end of activity were defined as the point at which at least 80% of the piglets

were asleep (= rested in one body position). The end of sleeping and start of activity were

characterised as the point at which at least 80% of the piglets performed movements (=

moving, suckling, elimination).

Table 1: Recorded behaviour according to videotape analyses

Behaviour Definition

Posture

Standing Upright body position on extended legs with hooves only

in contact with the floor

Sitting Partly erected on stretched front legs with caudal end of

body contacting the floor

Kneeling on front legs Kneeling with both carpal joints on the floor

Sternal recumbency Lying on abdomen with front and hind legs folded under

the body

Ventral recumbency Lying on abdomen with front legs folded under the body

and visible hind legs (right side, left side)

Lateral recumbency Lying on either side with all four legs visible (right side,

left side)

52

Sow’s lying position

Lying towards the piglet nest side Ventral, lateral recumbency with the legs visible towards

the nest

Lying averted from the piglet nest

side

Ventral, lateral recumbency with the legs visible turned

away from the nest

Behaviour

Looking around Looking down and to the right and left sides

Looking to the piglet nest side Looking to the side towards the piglet nest only

Looking away from the piglet

nest side

Looking to the side opposite the piglet nest only

Nosing Snout contact of the sow with or close to the piglet's snout

or body; snout contact of the piglet within one piglet

length in front of the sow’s snout

Sniffing Sniffing the floor before descending from standing to

lying

Table 2: Piglet locations

Piglet location Definition

Mammary gland At least 80% of the piglets resting at the mammary gland

of the sow

Piglet nest At least 80% of the piglets resting under the heat lamp of

the piglet nest

Crate area At least 80% of the piglets resting alone in the crate area

On the sow At least 80% of the piglets resting directly on the sow

(back, side, front, rear)

Between sow and piglet nest At least 80% of the piglets resting huddled together

between the sow and the piglet nest in the create area

2.4. Statistical analysis

The ‘sampling of all occurrences’ was used (Lehner, 1992) to generate accurate frequency

and duration of data. A block-data design was chosen to achieve data recording within a

reasonable expenditure of time. Out of 438 litters, 20 sows without any crushed piglets (NC-

53

sows) were randomly sampled by using the uniform distribution procedure (SAS, 2005). For

each NC-sow, one sow with one or more crushed piglets within the first 48 hours after

parturition (C-sow) was selected, using the matching criteria of parity and farrowing date

(season) (Table 3).

Table 3: Means ( x ), standard deviations (S.D.), minimum (min.) and maximum (max.) of the

reproductive traits of NC-sows and C-sows (n = 40)

Trait Unit x S.D. min. max.

NC C NC C NC C NC C

Total number born per litter Piglets 9.8 11.3 2.67 2.57 4 7 15 16

Number born alive per litter Piglets 9.2 10.2 2.73 2.28 4 6 13 14

Number stillborn per litter Piglets 0.6 1.1 1.50 3.24 0 0 4 6

Number of crushed per litter Piglets 0 1.4 0 0.67 0 1 0 3

Piglets’ deaths were assessed visually on the farm by the scientist conducting the study, and

crushing was determined in combination with video analysis. Crushing was characterised as

‘no movement of trapped piglet after a change in the sow’s posture’, as described by Vieuille

et al. (2003). The selected sows were healthy, showing a body temperature of below 39.5° C

within three days after parturition. Exterior traits were determined by a linear scoring system

before lactation (Hellbrügge, 2007). Only sows without extreme deviations were considered.

A block-data design was created arranging NC-sows and C-sows in pairs according to the

matching criteria. The parity number of pairs ranged from twelve pairs as gilts and eight pairs

from the third to the tenth parity with an average parity number of 2.35. Five pairs had their

farrowing date in March or April, ten pairs in May and June, and the rest in August and

September.

C-sows did not differ in comparison to NC-sows despite higher numbers of piglets born alive.

All litters were adjusted by cross-fostering post partum depending on the litter sizes per

farrowing group. The performance of sows and further data on the piglets were presented in

detail by Hellbrügge et al. (2008). The crushing mortality on the farm was 12.4%, with 8.8%

within the first three days (Hellbrügge et al., 2008). The total pre-weaning mortality value on

the farm was 15.7%, and 10.0% in the litters of the 40 sows analysed in the study.

Twenty C-sows which crushed 27 piglets within the first 48 hours post partum were analysed.

Seventy percent of these 27 piglets were crushed within the first 24 hours post partum. Two-

54

thirds of them were male with a mean body weight of 1.28 kg. The crushed piglets (n = 27)

had a mean body weight of 1.25 kg, while the non-crushed piglets of C-sows (n = 176)

weighed 1.54 kg and the piglets of NC-sows (n = 184) 1.63 kg. Crushing was performed in

63% of the incidents by the hindquarter, in 32% by the shoulder and in 5% by the back,

mostly while the sow performed ‘lying-down’ behaviour (Wischner et al., 2009).

All piglets of NC-sows were defined as NC-piglets, while all piglets of C-sows were

designated C-piglets. Their behavioural elements were analysed according to the sows’ data.

A linear model using the MIXED procedure of the SAS statistical software package (SAS,

2005) was applied to analyse the significance of the differences between NC-sows and C-

sows as well as between NC-piglets and C-piglets. The behavioural elements and the

associated residuals were not normally distributed. Consequently, normally distributed

residuals as a pre-condition of linear models were analysed by using differences calculated by

the subtraction of the behavioural elements of C-sows (C-piglets) from the respective

behavioural element of NC-sows (NC-piglets). Differences in independent random variables

were approximately normally distributed (central limit theorem).

The fixed effects of parity (‘first parity’ and ‘higher parities’), season for farrowing (‘March

to April’, ‘May to June’ and ‘August to September’) and time interval with ‘48 h after

farrowing’ were included in the model (peri-/ post partum).

Model:

Yijkl = µ + Pi + Sj + Tk + eijkl

with:

Yijkl = difference between NC-sows and C-sows (pairs) regarding respective behaviour

µ = overall mean

Pi = fixed effect of the i-th parity class (i = 1, 2)

Sj = fixed effect of the j-th season class (j = 1, 2, 3)

Tk = fixed effect of the k-th time (k = 0, …, 48 hour)

eijkl = residual effect

The differences are multiple measurements within a sow pair over a period of time. It is

supposed that the repeated measures are not independent and thus autocorrelated for such

datasets (Littell et al., 2006). Therefore, it is necessary to use applicable error covariance

structures for valid statistical inferences. For their ability to fit the model, different structures

were compared (AR(1), TOEP(4), UN) using the likelihood ratio test and criteria of Akaike

55

(1973) and Schwarz (1978). The first-order autoregressive model, AR(1), was chosen with

Covariance Parameter Estimates between 0.67 and 0.09. The significance of the fixed effects

was tested by the F-test implemented in the MIXED procedure in SAS (SAS, 2005). With

respect to the pre-conditions for linear models, homogeneity of variance was checked by plots

of the standardised residuals against the predicted values.

3. Results

The NC-sows, in particular primiparous ones, performed ‘sniffing’ as an element of pre-lying

behaviour significantly more often (P < 0.01) and with a longer duration (P < 0.01) than

primiparous C-sows. The means of ‘sniffing’ duration showed a decrease directly after

parturition, followed by an increase at the 24th and 36th hour post partum. The ‘sniffing’

duration was extended in NC-sows especially after the first day (Figure 2).

-60

0

60

120

180

240

1 7 13 19 25 31 37 43

hours peri-/ post partum

seco

nds

/ hou

r (L

SM

and

S

.E.)

-60

-40

-20

0

20

40

60

80

seco

nds

/ hou

r (m

ean)

differences (NC-C) in duration of 'sniffing' (LSM and S.E.)duration of 'sniffing' (mean)

Figure 2: Differences (NC-C) in duration of ‘sniffing’ (LSM and S.E.) related to crushing and

duration of ‘sniffing’ (mean) (n = 1,586)

Within the fixed effect of parity, ‘sniffing’ before ‘kneeling on front legs’ followed by ‘lateral

recumbency’ differed significantly (P < 0.05). Primiparous sows ‘sniffed’ more often than

multiparous ones before descending from standing to lying. Especially primiparous NC-sows

56

‘sniffed’ more often (P < 0.01) in comparison to primiparous C-sows before ‘kneeling on

front legs’ followed by ‘ventral recumbency’.

‘Looking around’ before descending from standing to lying and descending from standing to

lying from ‘standing’ directly into ‘ventral or lateral recumbency’ without ‘kneeling on front

legs’ did not differ between NC-sows and C-sows. ‘Looking around’ before ‘kneeling on

front legs’ was significantly affected by parity (P < 0.05). Multiparous sows performed this

behaviour more often than primiparous ones. Moreover, this behaviour was shown more

frequently by NC-sows.

‘Nosing’ is a significantly more frequent behavioural pattern in NC-sows, especially in

primiparous ones, than in C-sows (P < 0.01). Primiparous NC-sows ‘looked for nose-contact’

in average 3.8 times (LSM) more often than primiparous C-sows particularly in the time

frame of one hour to twelve hours post partum, The means of ‘nosing’ frequency, especially

in NC-sows, showed an increase after nearly half a day post partum (Figure 3).

-10

-5

0

5

10

15

20

1 7 13 19 25 31 37 43

hours peri-/ post partum

freq

uenc

y / h

our

(LS

M)

-10

-6

-2

2

6

10

14

freq

uenc

y / h

our

(mea

n)

first parity - differences (NC-C) in frequency of 'nosing' behaviour (LSM)differences (NC-C) in frequency of 'nosing' behaviour (LSM)frequency of 'nosing' behaviour (mean)

Figure 3: Differences (NC-C) in frequency of ‘nosing’ behaviour (LSM) related to crushing,

additionally only for the first parity and frequency of ‘nosing’ behaviour (mean)

(n = 15,682)

The combination of the behavioural patterns ‘looking around’ and ‘nosing’ was performed

more often by NC-sows than by C-sows. However, in combination with lying-down

57

behaviour or with ‘sitting’ or ‘standing’, no significant differences between NC-sows and C-

sows were analysed.

The sow’s manner of descending from standing to lying towards or averted from the piglet

nest did not influence or initiate the piglets’ willingness to fall asleep. The frequency and the

beginning and end of the piglets’ sleep period in any location did not differ between NC-sows

and C-sows. The duration of piglets’ sleeping behaviour varied at the mammary gland, but the

difference was not significant: C-piglets tended to sleep on average 1.28 minutes (LSM)

longer than NC-piglets in this position. The means were increased in C-piglets, with a

decreased tendency after the 18th hour post partum (Figure 4), particularly for sleeping at the

mammary gland.

-12

-6

0

6

12

18

1 7 13 19 25 31 37 43

hours peri-/ post partum

min

utes

/ ho

ur (

LS

M

and

S.E

.)

-8

-5

-2

1

4

7

10

min

tute

s / h

our

(mea

n)

differences (NC-C) in duration of 'sleeping' behaviour atmammary gland (LSM and S.E.)

duration of 'sleeping' behaviour at mammary gland (mean)

Figure 4: Differences (NC-piglets – C-piglets) in duration of sleeping behaviour at mammary

gland (LSM and S.E.) and duration of sleeping behaviour (mean) (n = 702)

The cycles of activity beginning and ending at the mammary gland were significantly

different between NC-piglets and C-piglets. On average, C-piglets performed an 11-minutes

(LSM) longer activity pattern than NC-piglets. Activity cycles starting and ending at the sow

were longer in C-piglets as well. No differences between NC- and C-piglets were detected

within the activity in the crate or between the sow and the piglet nest. Only in activity cycles

58

beginning and ending within the piglet nest did the NC-piglets – especially those of

primiparous NC-sows – show longer duration than C-piglets, on average 8 minutes (LSM).

4. Discussion

As stated by Blackshaw and Hagelsø (1990), confined sows seem to be unable to turn and

locate their piglets before lying down. However, the present study clearly shows that parts of

inherent behavioural patterns are performed in confined environments as far as possible.

In general, pre-lying behaviour such as rooting, pawing the ground, looking at and coming

into contact with the piglets is shown more frequently within the first day after farrowing

(Marchant et al., 2001; Damm et al., 2005; Pokorná et al., 2008). The major aim of these

behavioural patterns is to attract the piglets’ attention before the sow lies down and to give

them enough time to move (Marchant et al., 1996). In this way, this behaviour is directly

related to piglet losses due to crushing. In the present study, NC-sows performed all evaluated

pre-lying behaviour patterns significantly more often than C-sows, confirming the importance

of this behaviour for the piglets’ survival.

The pre-lying behavioural pattern ‘sniffing’ is part of general lying-down behaviour. Harris

and Gonyou (1998) reported ‘sniffing’ as common behaviour between sows and piglets in

non-confined conditions. In the crated environment in the present study, sows nevertheless

‘sniffed’ on the floor and looked around first before lying down. This is especially relevant

later on when piglets are resting in closer proximity. Particularly NC-sows performed

‘sniffing’ more frequently and with longer duration than C-sows, indicating the carefulness of

NC-sows towards their environment. This is in accordance with Jensen (1986) and Marchant

et al. (2001), who described ‘sniffing’ which led to contact with the piglets as maternal

behaviour. In contrast to this, Blackshaw and Hagelsø (1990) did not find any association

between the sow’s lying-down behaviour and behavioural patterns for checking the piglets’

location and for clearing the space.

‘Looking around’ is a further element of pre-lying behaviour (Marchant et al., 2001). In our

study, multiparous NC-sows performed ‘looking around’ more frequently before descending

from standing to lying than multiparous C-sows.

‘Nosing’ behaviour represents a social behaviour component, promoting the social bond

between the sow and her piglets. ‘Nosing’ was described as an important maternal response of

the sow, which affects the survival of the piglets (Ahlström et al., 2002), and is most

frequently shown in the first five minutes after milk ejection (Whatson and Bertram, 1982). In

contrast to Jensen (1988), who observed the first nasal contacts of free-ranging sows and their

59

piglets not before the end of the first week post partum, the primiparous NC-sows in

particular had their first nose-contact within the first twelve hours after parturition in the

present study. It also confirmed the results from Pedersen et al. (2003), showing that after the

initial active period shortly after parturition, sows rest in lateral recumbency and do not

respond to naso-nasal contacts by their piglets. Eventually, in a second phase, approximately

8 hours after birth, their maternal responsiveness to naso-nasal contacts increases. This is in

accordance with another study (Blackshaw and Hagelsø, 1990), suggesting that the

development of social behaviour is initiated by the sow on day one as well. The combination

of the behaviour patterns ‘looking around’ and ‘nosing’ was shown more often by NC-sows

than by C-sows. This emphasises the importance of these behavioural patterns for social

bonding and as a precautionary measure before changing position, demanding higher

responsiveness.

In the present study, no differences between the pre-lying behaviour of NC-sows and C-sows

were analysed with regard to the piglets’ location. In contrast to this, Pokorná et al. (2008)

reported more and longer pre-lying behaviour in sows when piglets were next to the sow or

clustered in proximity. With regard to the piglets’ activity, a rise in position or more frequent

changes in location before the sow descended from standing to lying were found neither in

NC-piglets nor in C-piglets. In their activity cycles, however, C-piglets stayed significantly

longer in the area with high crushing risk. Furthermore, activity cycles starting and ending in

the piglet nest were significantly longer in NC-piglets than in C-piglets. This suggests that the

NC-piglets huddled sooner in the piglet nest, putting themselves out of the risk zone. Even

though there is the provision of a heated creep area as a preventative measure against

crushing, reducing the time piglets spend next to the sow (Titterington and Fraser, 1975),

piglets tend to lie next to the sow regardless of heat lamp location or air temperature (Hrupka

et al., 1986). As shown by Hrupka et al., (1998), the heat lamp position and floor covering

under the lamp does not normally affect piglets’ survival in the first three days post partum.

The ‘sleeping’ duration of C-piglets at the mammary gland was longer compared to the NC-

piglets. Because C-sows preferred ‘ventral recumbency’ (Wischner et al., 2009), C-piglets

had to stay next to the mammary gland in order to gain teat access. Consequently, the risk of

crushing increased. How far these differences are related to an adequate milk intake was not

determined in our study, but these questions are promising approaches for further

examinations.

60

5. Conclusion

‘Sniffing’, ‘looking around’, and ‘nosing’ as essential parts of the pre-lying behaviour were

performed in significantly different ways in sows that crushed and did not crush piglets. The

study emphasises the existence of such differences and their inherent importance for the

reduction of piglet losses, even in confined environments. Due to the economical relevance of

the piglets’ survival and for animal welfare reasons, the assessment and evaluation of

maternal behaviour is gaining increasing importance. Improved and simplified recording of

maternal behavioural patterns might pave the way for studies on the genetic background of

these properties, offering an alternative way to sustainably improve sow productivity within

breeding programs.

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63

CHAPTER FOUR

Analysis of sows’ posture patterns in relationship to different behavioural tests of sows

Diane Wischner1, Nicole Kemper1, Imke Traulsen1, Eckhard Stamer2, Barbara Hellbruegge1,

Ulrich Presuhn3 and Joachim Krieter1

1Institute of Animal Breeding and Husbandry, Christian-Albrechts-University, 24098 Kiel,

Germany 2 TiDa Tier und Daten GmbH, Bosser Strasse 4c, 24259 Westensee/Brux, Germany

3 farm concepts GmbH & Co. KG, Heidmühlender Strasse/Moorhof, 23812 Wahlstedt,

Germany

64

Abstract

The aim of this study was to analyse different behavioural traits of sows in relationship to

several behavioural tests carried out pre- and post partum to determine the interrelation to

piglet losses. The behaviour of 386 German Landrace sows in a nucleus herd (with 438 pure-

bred litters) was videotaped continuously for one year starting 12 hours prepartum until 48

hours post partum. From these animals, 40 sows were randomly sampled with a block data

design. Twenty sows which crushed one or more than one piglet were compared to 20 sows

which crushed no piglets. Postural behavioural traits were documented according to duration

and frequencies of positions and analysed separately pre- and post partum (e.g. standing,

sitting, lying-down). Sows’ reactions within three different behavioural tests were examined:

separation of the sow from her litter after 24 hours post partum (SEPD1), after 21 days

(SEPD21) and playback of a piglet’s distress call after 4 days (SCREAM). The sows’

maximum of reaction was assessed in an ordinal scale from score 1 (no reaction) to score 5

(very strong reaction). Spearman rank correlations were used to calculate the behavioural

traits on the videotapes and the sows’ reactions in tests. In SEPD1, the sows’ responses were

positively correlated to behavioural patterns (e.g. ‘nest-building’, ‘activity’), except the

frequency of ‘rolling’ behaviour and duration of ‘resting’ behaviour. In SEPD21, the same

tendencies of correlations were analysed as in SEPD1. In SCREAM, the sows’ responses

were positively correlated to the frequency and duration in evaluated behavioural patterns,

especially for ‘nest-building’ behaviour prepartum and pre-lying behaviour post partum. The

results suggest that behavioural tests partly reflect sows’ maternal behavioural patterns which

can be important criteria to analyse piglet looses.

Keywords

Maternal ability; Responsiveness; Piglet scream test; Separation tests; Posture changes

1. Introduction

Piglet mortality due to crushing is accompanied by substantial economic losses for the farmer

(Grandinson et al., 2003). The selection of traits improving sow productivity has induced

larger litters at birth and postulated improved maternal care. But these larger litter sizes go

hand in hand with increased mortality rates (Roehe und Kalm, 2000). The most important

factor for the piglet’s survival is the sow’s behaviour during the lactation period (Gäde et al.,

2008). One indicator for maternal care is the responsiveness of the sow towards her offspring,

but this maternal responsiveness towards the piglets and the activity of the sow vary after

65

birth (Pedersen et al., 2003). Sows react more actively in the first two hours after birth,

changing their postures more often, and being more reactive to piglets’ approaches. After the

expulsion of the afterbirth, the responsiveness towards the piglets decreases, but increases

again after 12 hours post partum (Pedersen et al., 2003). The initial passivity of sows is

regarded as positive for the piglets, since they are allowed to suckle, while the risk of crushing

is reduced (Jarvis et al., 1999).

Recording maternal behaviour using videotapes is time-consuming and not feasible in

commercial stockbreeding situations. (Lensink et al., 2009). Thus, behavioural tests were

developed, partly implemented into routine work, to record behavioural traits of sows with

less time to be recorded under production conditions (Hellbrügge et al., 2008).

The reaction of the sow towards human interactions characterised in different behavioural

patterns is important for the survival of piglets, especially during the first days after

farrowing. Stronger reactions by the sow towards the stockperson can be expressed by

careless posture changes, increasing the piglets’ danger of being crushed (Lensink et al.,

2009). Under production conditions, stockpersons have to gain access to the piglets within the

first days after parturition (Chaloupková et al., 2008). At this time, the sow’s protectiveness is

expressed by the sow’s reaction during the time her piglets are handled (Grandinson et al.,

2003) and can be evaluated by the score of the separation test (Hellbrügge et al., 2008).

In the so-called piglet scream test, differences are measured between sows in their reactions to

tactile and vocal stimuli from the possibly endangered piglets (Hutson et al., 1991; Wechsler

and Hegglin, 1997). The slower the sow reacts and the longer the piglet is trapped beneath the

sow, the higher the piglet’s risk of dying (Weary et al., 1996). The chance for survival

increases when the sow reacts immediately. Vocal utterances of the piglets show a greater

effect compared to tactile stimuli (Cronin and Cropley, 1991; Hutson et al., 1991). Moreover,

Thodberg et al. (2002) observed that stronger reactions to piglets’ audio stimuli went along

with the performance of less risky movement behaviour. The responsiveness of the sows to a

sound of a screaming piglet has been used as an indicator of maternal behaviour (Grandinson

et al., 2003; Hellbrügge et al., 2008).

In this study, reactions measured in behavioural tests and occurring posture patterns pre- and

post partum were analysed. The aim of analysis was the evaluation of different behavioural

tests in relationship to behavioural traits. In this way, the behavioural tests were examined as

indirect traits implying the opportunity to improve the sows’ maternal features to reduce

piglet mortality.

66

2. Material and methods

2.1. Animals and environment

Animals of this study were kept in a nucleus herd of the German breeding company

‘Hülsenberger Zuchtschweine’. In total, data and videotapes of 386 Landrace sows with 438

pure-bred litters were recorded in the time period between January and December 2004. The

sows were managed in a one-week rhythm with a 21-day lactation period. During birth and

lactation, sows were fixed in diagonally ordered farrowing crates of homogeneous type with

dimensions of 2.74 m x 1.75 m during lactation. No nesting material was provided for the

sows. Twenty sows were penned per farrowing batch, ordered by the calculated farrowing

date. In the farrowing crate, underfloor heating and heat lamps were provided. The piglet nest

area was located laterally in front of the sow’s head. From the first day the sows were fed

once per day, and from the second day post partum twice per day.

2.2. Sampling of animals

A block data design of 40 animals out of this population was chosen to perform data analysis.

Twenty sows without any crushed piglets were randomly sampled by using the uniform

distribution procedure (SAS, 2005). Sows with one or more crushed piglets within the first 48

hours after parturition were selected conforming to the group of sows without any crushed

piglets, considering the matching criteria number of piglets born alive, parity and farrowing

date (season). The 40 sows selected were healthy, which was determined by body temperature

(max. 39.5° C) within three days after parturition and evaluation of the exterior trait without

extreme deviations determined by a linear scoring system before lactation, as described

previously (Hellbrügge, 2007). All litters were adjusted by cross-fostering post partum,

depending on the litter sizes per farrowing group (Table 1).

Table 1: Means ( x ), standard deviations (S.D.), minimum (min.) and maximum (max.) of the

reproductive traits of sows (n = 40)

Trait

S.D. min. max.

Total number of piglets born per litter 10.5 2.7 4.0 16.0

Number of piglets born alive per litter 9.7 2.5 5.0 14.0

Number of stillborn piglets per litter 0.8 1.5 0.0 6.0

x

67

2.3. Behavioural traits on videotapes

Video recording was accomplished by use of the HeiTel Player software program (HeiTel

Digital Video GmbH, Kiel). Movement patterns (frequency, duration, transition of posture) of

the sows were continuously observed from overhead within the period 12 hours before

parturition up to 48 hours after parturition. Data was analysed by one person, considering the

frequency (f; number per hour) and the duration (d; seconds, minutes or hours) of the

behavioural traits since Lehner (1992) proposed ‘sampling of all occurrences’ as the method

of choice to generate accurate frequency and duration data. Furthermore, a self-written

database was used to create data files for SAS (SAS, 2005). The recorded single behavioural

traits are given in Table 2.

Table 2: Recorded behavioural traits according to videotape analyses (modified by Lou and

Hurnik, 1998)

Trait Definition Time of

observation

Standing Upright body position on extended legs with

hooves only in contact with the floor

Pre-/ post partum

Sitting Partly erected on stretched front legs with caudal

end of body in contact with the floor

Pre-/ post partum

Kneeling on front

legs

Kneeling with both carpal joints on the floor Pre-/ post partum

Sternal recumbency Lying on abdomen with front and hind legs folded

under the body

Pre-/ post partum

Ventral recumbency Lying on abdomen with front legs folded under the

body and visible hind legs (right side, left side)

Pre-/ post partum

Lateral recumbency Lying on either side with all four legs visible (right

side, left side)

Pre-/ post partum

Nest-building Continuously oronasal contact with floor and head

movements

Prepartum

Rolling All occurrences of postural changes between lying

on one side to lying on the other side (side-

swapping)

Prepartum

Sniffing Sniffing the floor before descending from standing Post partum

68

to lying

Nosing Snout contact of the sow with or close to the

piglet's snout or body; snout contact of the piglet

within one piglet length in front of sow’s snout

Post partum

Looking around Looking down and to the right and left sides Post partum

Activity Standing + sitting + kneeling in front of legs Pre-/ post partum

Resting Sternal- + ventral- + lateral recumbency Pre-/ post partum

2.4. Behavioural traits in tests

Behavioural tests were performed as described in Hellbrügge et al. (2008). A separation test

was performed within the period 24 hours after parturition (SEPD1) and before weaning after

21 day post partum (SEPD21). The sow’s reaction to the separation from her piglets was

noted with emphasis on the strongest sow reaction shown during the test. Additionally, the

sow’s initial position before the piglets were removed, and the sow’s final position were

documented when the piglets were relocated.

Furthermore, a scream test (SCREAM) was made after the farrowing of all sows in one batch

(in average four days post partum). Loudspeakers were placed in the central corridor for about

two hours in order to customise the sows to the hi-fi system. When all sows were lying in

lateral recumbency, the playback sound started with the scream test, a 30-second piglet

distress call was played from a cassette and the sows’ reaction of posture changes was

documented in an ordinal scale with five scores (Table 3).

Table 3: Definition and percentage (%) of the behavioural test score

(modified by Hellbrügge et al., 2008)

Score Definition SEPD1

(n = 40)

SEPD21

(n = 40)

SCREAM

(n = 40)

% % %

1 No reaction

(e.g. sow remains in recumbent position)

20.0 10.0 2.5

2 Little reaction

(e.g. sow raises head)

22.5 22.5 12.5

3 Medium reaction 22.5 37.5 57.5

69

(e.g. sow sits up)

4 Strong reaction

(e.g. sow stands up)

35.0 30.0 27.5

2.5. Statistical analysis

Data were analysed using SAS (SAS, 2005). Correlations between behavioural traits on the

videotapes (Table 2) and scores of behavioural tests (Table 3) were analysed pre- and post

partum. As a normal distribution could not be assumed for all data, Spearman rank

correlations (r) were calculated between the behavioural traits on the videotapes and the sows’

reaction in the tests. Therefore observations of behavioural traits on the videotapes were

averaged per time period (prepartum and post partum, Table 4). Results with an associate

probability of less than or equal to 0.05 were considered as significant, while results with

associated probability between 0.05 and 0.1 were considered as tendencies.

Table 4: Means ( x ), standard deviations (S.D.), minimum (min.) and maximum (max.) of the

traits on videotapes per observation period and behavioural tests (n = 40)

Trait x S.D. min. max. Time of

observation

Nest-building f * 5.8 4.4 0.7 20.0 Prepartum

Nest-building d ** 196.3 154.6 19.0 499.8 Prepartum

Rolling 0.9 1.2 0.0 4.2 Prepartum

Activity f * 19.6 8.6 5.2 42.8 Prepartum

Activity d ** 1031.0 496.2 253.2 2136.0 Prepartum

Resting f * 9.9 4.8 2.9 25.8 Prepartum

Resting d ** 2462.0 508.1 1461.0 3346.0 Prepartum

Sniffing f * 0.8 0.7 0.0 3.4 Post partum

Sniffing d ** 31.6 28.5 0.0 133.7 Post partum

Nosing f * 8.2 3.8 2.0 23.6 Post partum

Looking around f * 0.9 0.5 0.1 2.1 Post partum

Activity f * 3.8 1.4 1.5 6.9 Post partum

Activity d ** 259.9 99.7 78.4 475.0 Post partum

Resting f * 2.3 1.1 0.8 4.8 Post partum

Resting d ** 3320.0 100.0 3104.0 3515.0 Post partum

70

SEPD1 2.7 1.2 1.0 4.0

SEPD21 2.9 1.0 1.0 4.0

SCREAM 1.9 1.0 1.0 4.0

(* f = frequency ; ** d = duration)

3. Results

Positive correlations were found between SEPD1 and ‘nest-building’ behaviour (Figure 1).

More reactive sows in tests performed more frequent (r = 0.28) and longer (r = 0.24) ‘nest-

building’ behaviour as well as longer bouts of ‘activity’ behaviour (r = 0.29). Duration in

‘resting’ behavioural patterns (r = -0.12) was negatively correlated towards the sows’

reactions in SEPD1. All correlations were considered insignificant. Similar results were found

in SEPD21.

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

Spe

arm

an C

orre

lati

on C

oeff

icie

nt

SEPD1 prepartum SEPD21 prepartum

(f = frequency; d = duration)

Figure 1: Correlations between different behavioural traits prepartum and sows’ reactions in

SEPD1/ SEPD21 (n = 40)

Nest- building f

Nest- building d

Rolling f

Activity f

Activity d

Resting f

Resting d

71

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

Sper

aman

Cor

rela

tion

Coe

ffic

ient

SEPD1 post partum SEPD21 post partum

(f = frequency; d = duration; * P < 0.05)

Figure 2: Correlations between different behavioural traits post partum and sows’ reactions in

SEPD1/ SEPD21 (n = 40)

After parturition, behavioural traits were similary correlated in SEPD1 as prepartum (Figure

2). ‘Activity’ was positively correlated and the duration of ‘resting’ was negatively correlated

in SEPD1. The only significant rank correlation was calculated between the frequency of

‘sniffing’ and the sows’ reactions in SEPD1 (P < 0.05, Figure 2).

Activity f

Rolling f

Activity d

Resting f

Resting d

*

Snif- fing f

Snif- fing d

Nosing f Looking around f

72

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

Spe

arm

an C

orre

lati

on C

oeff

icie

ntSCREAM prepartum SCREAM post partum

(f = frequency; d = duration; * P < 0.05; ** P < 0.01)

Figure 3: Correlations between different behavioural traits pre- and post partum and sows’

reactions in SCREAM (n = 40)

Sows with higher scores in SCREAM had a tendency to perform longer (r = 0.30) and more

frequent (r = 0.34; P < 0.05) ‘nest-building’ behaviour prepartum (Figure 3). ‘Rolling’

behaviour (r = 0.19) as well as longer bouts of ‘activity’ behaviour (r = 0.29) were positively

correlated with more reactive sows. Only the ‘resting’ behaviour in general was negatively

correlated (r = -0.05; r = -0.26) towards sows with more reaction in SCREAM.

Post partum, more reactive sows in SCREAM performed tendentially higher frequencies and

longer durations in all calculated behavioural traits expect the duration of ‘resting’ behaviour

(r = -0.36) and ‘nosing’ behaviour (Figure 3). Significant rank correlations were only

calculated for ‘sniffing’ (P < 0.05) and ‘looking around’ behaviour (P < 0.01) with more

reactive sows in SCREAM post partum.

4. Discussion

In this study, behavioural tests indicating a sow’s maternal ability were tested in relation to

different behavioural traits. Frequencies and durations of ‘nest-building’ behaviour prepartum

Rol- ling f

Acti- vity f

Acti- vity d

Res- ting f

Res- ting d

Snif- fing f

Snif- fing d

No- sing f

Look- ing around f

Nest- buil- ding f

Nest- buil- ding d

* * *

** *

*

73

were positively correlated with sows, which had a higher test score in SEPD1, indicating a

stronger protective reaction by the sow towards her piglets within the first day post partum.

‘Nest-building’ behaviour is an important part of innate maternal behavioural patterns

prepartum (Wischner et al., 2009). Sows showing distinctive ‘nest-building’ behaviour and a

high response to separation can be regarded as responsive mothers. Positive correlations

between test scores and the duration of ‘activity’ behaviour hint to more reactive sows

prepartum. These results were consistent with the assessed negative correlations between

sows’ reactions in SEPD1 and ‘resting’ behaviour.

Post partum, sows showing higher test scores in SEPD1 were more active in most behavioural

traits. The basis for a strong reaction in SEPD1 is a well developed bond between sow and

piglets. This bond is established by ‘sniffing’ as part of the pre-lying behaviour, also coming

into contact with the piglets before the sow descends (Marchant et al., 2001).

When evaluating the use of SEPD1, two points have to be considered: on the one hand, a

highly responsive sow is preferred, but on the other hand, calmer sows with less frequent

posture changes, passivity and lateral lying allow their piglets full access to the teats (Damm

et al., 2000). Furthermore, test results can be influenced by a possible weakness of the sow

shortly after parturition, followed by slow reactive behaviour (Hellbrügge et al., 2008).

In SEPD21, the correlation of ‘resting’ and ‘nosing’ behaviour and reaction of the sows was

positive related. This emphasises the importance of ‘resting’ behaviour, essential for the

piglets’ milk supply (Jarvis et al., 1999). ‘Nosing’ as part of suckling behaviour intensifies the

contact between the sow and her piglets described by Whatson and Bertram (1982) and

simultanously improves the survival of the piglets (Ahlström et al., 2002). In SEPD21,

correlations were weaker and more heterogenous compared to correlations in SEPD1 pre- and

post partum. This might be due to the time interval between the behavioural observations and

the test, which took place three weeks later. This means that the behavioural test SEPD21 is

not feasible to describe maternal behaviour defined by behavioural traits.

In SCREAM, sows showing stronger reactions performed ‘nest-building’ prepartum more

often and for longer periods. Different and complex stimuli have effects on the performance

of ‘nest-building’ behaviour. In SCREAM, only the acoustic component was tested, while

stimuli of a tactile nature were neglected. However, behavioural reactions towards an acoustic

stimulus indicate well developed mothering abilities. Sows with higher reactions in SCREAM

performed ‘rolling’ movements more often pre- and post partum. Their more frequent

‘rolling’ movements might imply their high response to the piglet scream. A fast reaction to

the scream can prevent piglets, possibly trapped after ‘rolling’, from being crushed (Thodberg

74

et al., 2002; Vieuille et al., 2003). Prepartum, the frequency and duration of ‘activity’

behaviour was positively correlated in SCREAM. Sows which performed more posture

changes prepartum were more responsive to a piglet distress call after farrowing.

Furthermore, ‘sniffing’ was analysed more often and for longer periods post partum in sows

with high scores in SCREAM, suggesting a conformance between the tactile and acoustic

nature of these active and reactive behavioural patterns. The frequency of ‘looking around’

behaviour was positively correlated in SCREAM. ‘Looking around’, also performed as ‘pre-

lying’ behaviour, expresses the sow’s attentiveness towards the environment and her piglets

(Marchant et al., 2001). The reaction to SCREAM is also based on this attentiveness.

5. Conclusion

Posture patterns and behavioural tests are indicators of maternal ability in sows. Individual

variations in posture patterns contribute crucially to the reproductive success of the sow. The

use of behavioural tests alone to define sows with good maternal behaviour is difficult.

Further research should concentrate on more suitable behavioural traits to evaluate maternal

ability in sows in test situations.

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Genetic parameters for maternal behaviour traits in sows. Livest. Sci. 114, 31-41.

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GENERAL DISCUSSION

The pre-weaning death of piglets is a problem with economic and animal welfare

consequences in modern pig production (English and Morrison, 1984). Crushing by sows has

commonly been reported as the major cause of losses in born-alive piglets (Svendsen et al.,

1986). The definition of crushing, and thus inter-study comparability, is difficult. On the one

hand, the on-farm diagnosis of crushing piglets is hard to perform, because missing

observation often ends in misdiagnosis (Edwards, 2002). On the other hand, the correct

interpretation of data within the chronological context is difficult. For instance, starvation,

caused by reduced or inadequate food intake can serve as the primary cause for piglet death.

Malnourished piglets tend to spend more time next to the sow (Weary et al., 1996), and are,

furthermore, too weak and slow to react quickly enough to the body movements of the sow.

Often this starvation itself is only a secondary reason for piglet death. Starvation is caused by

several unfavourable circumstances, such as perinatal hypothermia in the piglets (Edwards,

2002) or post partum dysgalactia syndrome in the sow (Gerjets and Kemper, 2009), resulting

in an insufficient colostrum intake. Such immune-reduced piglets are more likely to be

crushed than healthy piglets (Fraser, 1990).

In this thesis, sows that definitely caused the death of at least one piglet by crushing were

defined as crusher-sows (C-sows). These C-sows were compared to non-crusher-sows (NC-

sows) which did not crush any piglet. As in practice, the reasons for and the manner of

crushing were not further analysed. Only sows which crushed one or more piglets within the

first 48 hours after birth were chosen, because in this time frame, the risk of crushing is

highest (Svendsen et al., 1986).

To reduce piglet mortality and especially losses due to crushing, farrowing crates were

developed (Edwards and Fraser, 1997). They were designed to restrict wide-ranging body

movements of the sow and to create a safe area for the piglets outside the crate beyond the

sow’s reach. Due to the confinement by the crate, sows were subsequently restricted in their

pre-parturient behaviour. They were prevented from choosing a nest-site and could not

perform ‘nest-building’ behaviour, as it is typical for pigs (Jensen 1989). However, research

on alternative farrowing systems allowing more space for the sows showed an increased

crushing risk for piglets. Nevertheless, the growing public concern about intensive livestock

production has led to major doubts on farrowing crates. The effectiveness of farrowing crates

in reducing piglets mortality caused by crushing is being discussed more and more

78

controversially, and the actual influence of the individual sow’s maternal ability is becoming

increasingly important.

Maternal behaviour

Information on the genetic variation of maternal ability in sows is rare and available

heritabilities are generally low (Henne, 1996; Grandinson et al. 2003; Gäde et al., 2008;

Hellbrügge et al. 2008). Furthermore, the trait ‘maternal ability’ is complex, combining

several aspects of maternal behaviour (Figure 1).

Figure 1: Traits that are used to measure maternal ability of sows. Traits regarded in this

study are marked grey.

Most aspects of the maternal behaviour of sows have not changed significantly by

domestication (Špinka et al., 2000). Though, variability in maternal behaviour exists between

sows, and especially the frequency of posture changes and the quality of lying-down

movements have been used previously as indicators for maternal protectiveness (Wechsler

and Hegglin, 1997). Špinka et al. (2000) demonstrated that the traits of locomotion manner,

protectiveness and nursing activity in domestic and feral pigs are not related to each other and

79

therefore should be considered separately. This indicates that maternal behaviour cannot be

described sufficiently by ‘emotionality’ or ‘temperament’ in the narrow sense, but is a

complex trait with more than one dimension.

Prepartum – ‘Nest-building’ behaviour

‘Nest-building’ behaviour in Suidae (pig) represents unique maternal behaviour which cannot

be noticed in other ungulates or mammals in general. It is an important part of the

reproductive behaviour of sows, taking place in the periparturient period. It is performed

without any differences between breeds of different local origin, as shown by the comparison

of ‘nest-building’ behaviour in very fertile Chinese breeds and European breeds (Meunier-

Salaün et al., 1991).

If appropriate space and material are available, sows build a farrowing nest that provides

shelter for their piglets, particular with respect to thermoregulation. The sows’ will to build a

nest is not prevented by confinement. The behavioural pattern was divided into a preparing

internally regulated phase, characterised by the digging a shallow hole, and into a subsequent

material-oriented phase with the actual ‘nest-building’, which depends more on the feedback

from the nest-site and on external stimuli (Jensen, 1993). The decreased performance of the

material-oriented behaviour in crated sows, and additionally, a strong tendency for longer

‘nest-building’ phases may be caused by reduced possibilities to achieve feedback from the

nest-site (Damm et al., 2003). This lack of satisfactory feedback could be stressful and result

in higher heart rates before farrowing (Jensen and Toates, 1993). If bedding is provided, the

comfortable lying area can serve as feedback stimuli, giving ‘udder comfort’ to the sows

(Baxter, 1983).

‘Nest-building’ behaviour of pigs is based on fixed action patterns, and is already performed

in its basic elements by six-day old piglets (Gundlach, 1968). ‘Rooting’, ‘pawing’,

‘mouthing’, ‘gathering’, and increased restlessness associated with ‘nest-building’ behaviour

occurs most distinctly 12 hours before farrowing (Algers and Uvnäs-Moberg, 2007). The

intensity of ‘nest-building’ behaviour depends on the environmental surroundings. Moreover,

age, parity or previous housing experiences could affect ‘nest-building’ (Thodberg et al.,

1999). In free-ranging sows, nest material is gathered dependent on the habitat, the season and

its properties to stake, stuff or protect (Arey et al., 1991). Ickes et al. (2005) reported a

profound impact of the ‘nest-building’ of wild sows on the scrub vegetation in primary

lowland rain forests in Malaysia and Sumatra. However, farrowing crates and slatted floors

without nest material hinder much of the ‘nest-building’ behaviour, even though many of the

80

behavioural elements are still present. Crated sows showed ‘nesting-like’ behaviour, for

instance the unsuccessful gathering of nesting material with the mouth, resulting in rooting

and mouthing of the pipes and waterers, since only these items were available for oral

manipulation (Hartsock and Barczewski, 1997). The animals grind their teeth, bite and root at

the rails. Such activities can lead to injuries and apparent exhaustion (Hansen and Curtis,

1980). Farrowing in crates tends to be more stressful than in pens with nest material, even if

adaption to crate environments occurred (Jarvis et al., 2001). With the implementation of the

EU Directive 2001/88/EC, this stress might be increased, since all sows have to be loose-

housed during the majority of the gestation period, but are moved to the restricted

environment of farrowing crates before parturition (Boyle et al., 2000). The consequences of

stress in the peripartum period are various: Besides the restraint-stillbirth hypothesis (Baxter

and Petherick, 1980), an increased risk of crushing of newborn piglets during parturition has

been documented (Thodberg et al., 1999). Moreover, stress results in slower parturition times

(Cronin et al., 1994), and a decreased duration of suckling time and an increased number of

suckling sessions terminated by the sow (Herskin et al., 1999). Lower responsiveness to piglet

distress calls have been reported as well (Thodberg et al., 2002). Nest material is usually not

offered, resulting in a more passive behaviour prior to farrowing and increased activity at the

beginning of farrowing (Cronin et al., 1993). With more space and the provision of adequate

nest-building material, maternal behaviour and sows’ welfare have improved, leading to

higher survival and growth rates in piglets (Damm et al., 2003). On the contrary, alternative

spacious housing systems result in similar piglet mortality rates as observed in conventional

systems (Weber et al., 2007). However, enriched environments and the selection of sows

showing a genetic determination for positive maternal behaviour might offer an opportunity to

reduce these losses (Johnson et al., 2007).

‘Locomotion’ behaviour

In the present study, increased activity behaviour in terms of postural changes was performed

especially in primiparous NC-sows. Recent studies have reported a peak of ‘activity’ in the

period about 12 hours before farrowing (Jensen, 1989). Especially ‘standing’, accompanied

by more frequent and longer periods of ‘nest-building’ behaviour, was performed by NC-

sows. Due to the restricted feedback mechanisms in crates (Damm et al., 2003), only

fragmented ‘nest-building’ behaviour was observed. Although no nest material was available,

differences between NC-sows and C-sows were recognised: NC-sows performed ‘nest-

building’ behaviour longer and more frequently. The observation of Heckt et al. (1988) that

81

pre-farrowing behaviour is important for piglets’ survival was confirmed. In contrast to this,

Pedersen et al. (2006) described that the passivity of sows, represented by low ‘nest-building’

activity, was followed by low post partum motivation for behavioural patterns and resulted

therefore in safer postural changes for the piglets. Lower ‘nest-building’ activity, as shown by

C-sows, was followed by higher piglet mortality. Higher activity patterns before birth, longer

‘lateral recumbency’ and calmness after birth, which improved the supply of milk for the

piglets, were reported for the NC-sows. On the contrary, Weary et al. (1996) did not find any

relationship between behaviour patterns and piglets’ mortality. Many different environmental

and genetic factors influence the behaviour (Figure 2).

Figure 2: Factors influencing sows’ behaviour

The performance of posture patterns such as descending and ascending movements in a

controlled manner depend on body control. This can only be conducted by sows on

comfortable flooring without physical impairments such as poor leg constitution,

inappropriate body size or a lack of muscular strength.

Diseases, especially post partum dysgalactia, bad leg constitution or obesity make sows’

movements highly dangerous for the piglets, since the sow is less careful or her ability to

control the movement changes is reduced (Damm et al., 2005). Pain could be followed by

carelessness towards the piglets and a higher risk of crushing. At higher parities, the sows

gain body weight, leg problems increase, and litters become more irregular with respect to the

82

piglets’ growth (Weary et al., 1998), resulting in an increased risk of crushing. Diseases can

also cause a lack of milk, weakening the piglets and resulting in a higher exposure to

crushing. In our study, the standardisation of conditions led to the exclusion of diseased sows.

Only healthy sows with non-febrile body temperature (max. 39.5° C) and fundamental

correctness, proven by a linear scoring system, were included in the study. In this way, it was

possible to evaluate behaviour movement patterns without any effects on health. Additionally,

a sufficient food supply, matched to individual demands, is essential for sows’ health.

Decubital ulcers and abrasions in thin sows could restrict or change movement patterns.

Medical treatments, such as the administration of hormones, were not assessed in our study,

but can influence maternal behaviour (Widowski and Curtis, 1989; Castrén et al., 1993). In

most intensive sow productions, sows change from their loose-housed group to individual

crates one week before farrowing. Especially for primiparous sows, this might go along with

stress because of the new environment and the physical separation. In multiparous sows,

already accustomed to the crates, stress might be caused by the association of the crated

situation with parturition and natal pain. A reduction of stress, resulting in higher embryo

survival (Baxter and Petherick, 1980) can be achieved by enriched environments.

Stress and its consequences during parturition, including the ‘nest-building’ activity

prepartum, is often shown by higher activity expressed by increased restlessness and

significant larger number of postural changes (Marchant and Broom, 1993; Jarvis et al.,

2001). Therefore, the evaluation of posture changes and activity patterns can be used to assess

sow welfare in husbandry systems. Furthermore, and even more important, these behaviour

analyses offer a way to evaluate the maternal ability of the sows.

Post partum – ‘Pre-lying’ behaviour

Parts of inherent behavioural patterns are performed in altered, confined environments as far

as possible. This was shown for ‘pre-lying’ behaviour in crated sows such as ‘rooting’,

‘pawing the ground’, ‘looking at’ and ‘coming into contact’ with the piglets, especially in the

first day after farrowing (Marchant et al., 2001; Damm et al., 2005; Pokorná et al., 2008). In

contrast to this, Blackshaw and Hagelsø (1990) stated that confined sows were unable to turn

and locate their piglets before ‘lying-down’. In this study, NC-sows performed ‘pre-lying’

behavioural patterns significantly more often than C-sows. The major aim of these

behavioural patterns is to attract the piglets’ attention before the sow changes from ‘standing’

to ‘lying’, giving them enough time to move.

83

The behaviour ‘sniffing’ in combination with ‘looking around’ was performed before ‘lying-

down’ in order to check the piglets’ location and to clear the space. This indicated a kind of

carefulness of NC-sows towards the piglets and their environment.

Naso-nasal contact between the sow and the piglet is mostly shown as part of the suckling

behaviour, initiating milk-ejection (Whatson and Bertram, 1982). The complex behavioural

features of nursing behaviour as described by Algers (1993) or neo-nursing and cyclic-nursing

(Lewis and Hurnik, 1985) could not exactly be determined in the videotapes. Therefore,

nursing as a component of maternal behaviour was not considered, neither were the four

phases of nursing order development (Hartsock and Graves, 1976) and sucking behaviour

phases (Fraser, 1980). ‘Nosing’ behaviour was regarded as a ‘social’ behaviour component,

promoting the social-bonding between sow and piglet. ‘Nosing’ was assessed as an important

maternal response of the sow, which affects the survival of the piglets (Ahlström et al., 2002).

With the development of the mother-young relationship, maternal care was possibly

improved, to be more responsive to piglet stimuli e.g in a trapped situation. This reactive

behaviour of the sows was often determined as the basis and the origin for their interaction

with the piglets. Blackshaw and Hagelsø (1990) claimed that the behaviour of the sow

towards her piglets was totally reliant on the piglets’ behaviour towards the sow and therefore

only reactive. This could not be confirmed by our study. The combination of the behaviour

patterns ‘looking around’ and ‘nosing’ clearly showed the importance of these movements for

social-bonding and as a precautionary measure before changing position, resulting in a higher

responsiveness before ‘lying-down’.

Concerning the piglets’ activity, the first three days in the piglets’ life are spent in direct

proximity to the sow, whether ‘active’ behaviour or ‘resting’ behaviour (Blackshaw and

Hagelsø, 1990). During this time, ‘pre-lying’ behaviour is essential for the survival of the

piglets. In our study, increased ‘activity’ or more frequent changes of location before the

sow’s descent could be found neither in NC-piglets nor in C-piglets. These results suggest

that not only the mechanical performance of posture patterns, but also the individual

carefulness of the sow is important. Piglets generally look for the satisfaction of all their

olfactory, acoustic and tactile needs (Hrupka et al., 2000). This is usually provided by the

sow, and therefore, they try to keep in proximity (Welch and Baxter, 1986). With heated

creep areas, the time piglets spent next to the sow should be reduced. Hrupka et al. (1998)

proclaimed that this only works after the third day post partum. Because of different optimal

temperatures for piglets and sows, the heated area should not be too close to the sow’s crate.

The dams are negatively affected by high temperatures (Algers and Jensen, 1990), possibly

84

followed by reduced milk production and decreased motions endangering the piglets. Because

of the lower milk intake, the piglets stay next to the udder, additionally increasing the

crushing risk. Definite temperature gradients in the environment support the sow’s health and

welfare and help piglets to find their way to the udder and back to the heated creep area.

Generally, good maternal behaviour, characterised by the performance of ‘pre-lying’

behaviour, is based on the intensive social-bonding between mother and offspring and offers

responsiveness, attentiveness, and protectiveness towards the offspring, and results in higher

survival rates (Grandinson, 2005).

Behavioural tests

One way to evaluate sows’ maternal behaviour are behavioural tests. In this study, the

separation test after birth (SEPD1), the separation test at 21st day (SEPD21) and the piglet

scream test (SCREAM) were used. The sows’ maximum of reaction was assessed and

classified into different test scores (score 1 to score 5), which were analysed in relationship to

different posture patterns pre- and post partum. Different correlations of behavioural test and

respective behavioural traits pre-and post partum were observed. Slight tendencies were

recognisable, but the low numbers of animals have to be considered, resulting in controversial

and/or low correlations of behavioural traits and behavioural tests.

For all tests, the restriction by the crate was not regarded. Additional difficulties can be

attributed to the insufficient congruence of the behavioural tests and the assessed locomotion

pattern: in posture patterns, the pure action is described, while in the tests, the role of

additional factors such as responsiveness, carefulness and protectiveness should not be

underestimated. Regarding the practical use of the test, especially in SEPD1, its restriction

should be kept in mind: results could be falsified due to the possible weakness of sows shortly

after birth and the following low expression of reactive behaviour (Hellbrügge et al., 2008).

Better results are expected in SEPD21 because piglet losses are reduced in more reactive sows

in SEPD21 (Hellbrügge et al., 2008). In our study, sows showing distinctive ‘nest-building’

behaviour and a high response towards separation can be regarded as responsive mothers.

However, correlations between SEPD21 and different behavioural traits were tendentially less

distinctive than between SEPD1 and different behavioural traits. This might be dependent on

the time interval between the performance of the behavioural tests and the behavioural

observations. In SCREAM the comparison with posture patterns is probably complicated by

the different nature of the stimuli. For instance, the comparison of ‘nest-building’, as active

behaviour mainly influenced by internal influences and external stimuli of tactile nature

85

(Jensen, 1993), and SCREAM, demanding a reactive behaviour regarding acoustic signals

(Hutson et al., 1991), is difficult. However, with regard to the positive correlations in the

behavioural traits, SCREAM seemed to give the most suitable hints to the mothering ability.

Another problem in the rating of behavioural test scores is the comparability with other

behavioural tests in literature, since the tests are not standardised. Different traits with varying

definitions to characterise the maternal ability have been used. Additionally, the evaluation of

single traits has been recorded with different scaling, and the ranking is not always within the

full bandwidth of variance. In practice, the implementation of such surveys into routine work

faces difficulties, and may reduce the attention to the given behaviour notes. It is very

important to develop tests which can be easily introduced into practical management without

extra time for acquisition and labour. The video analyses used in our study are not feasible on

farms. Especially the continuous evaluation is only possible on research farms, as long as no

advanced techniques such as video analysis with automatically image recognition are

available. One conceivable approach is documentation with time-sampling rates and the

automated assessment of posture patterns, used in an early warning system (Cornou, et al.,

2008). For instance, Oliviero et al. (2008) described differences in behavioural patterns

around farrowing as a tool for automatic parturition control. Human supervision at farrowing

can reduce perinatal piglet mortality by half (Oliviero et al., 2008), but high costs for working

hours are required. Besides the measuring of body temperature and respiratory rates, the

assessment of different movements can provide more details for effective work organisation

(Oliviero et al., 2008). A further future approach could be the registration of prepartal

behavioural patterns in sows via sensors, possibly integrated in the earmark, similar to

pedometers in cows. The measurement of pressure distribution on the lying surface of the

crate represents another attempt at an early warning system, perhaps integrated in a MIS

(management information system). Another type of analysis is animal vocalisation, which

allows the interpretation of stress patterns in a non-invasive way (Manteuffel et al., 2004). It

may be used to assess animal welfare as well as health status and social adaptation. Audio

information was not collected on the time-lapsed video records in our study. However

introducing automatically audio measurements in practice to identify diseased sows could be

an option for future research.

86

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91

GENERAL SUMMARY

This thesis focused on the behavioural background of sows and the relationship to crushing

piglets. In particular, the locomotory and the responsive behaviour of sows towards their

piglets and the impact of the piglets’ activity were analysed. Behavioural tests were

performed to investigate and evaluate various important behavioural traits.

The behavioural elements of ‘nest-building’ behaviour of the sows were presented in chapter

one as a review. ‘Nest-building’ is an important part of maternal behaviour strongly related to

reproductive abilities in sows. Pre-farrowing behavioural patterns are mainly characterised by

‘nest-building’ activities, resulting in a nest that provides shelter for the piglets. In the course

of domestication, sows have not lost their innate behaviour to build a nest and perform at least

elements of it when appropriate space and materials are available. The possibilities to perform

‘nest-building’ can be restricted to different extents in commercially farmed pigs. Although

they are kept in different modern housing systems, sows need ‘nest-building’ performance as

part of the natural behavioural patterns. With regard to the increased demands for animal

welfare and following changes in the legislation for pig husbandry, possible consequences for

different housing systems were discussed.

The following chapters were based on the same data. The present dataset was recorded in a

nucleus herd of the German Breeding company ‘Hülsenberger Zuchtschweine’ for one year

and consisted of 438 litters recorded from 386 pure-bred German Landrace sows. All sows

were videotaped continuously starting 12 hours ante partum until 48 hours post partum. From

the population, sows were randomly sampled in a block data design considering different

matching criteria (number of piglets born alive, parities and farrowing date). Forty sows were

compared: twenty sows that crushed more than one piglet (C-sows) and 20 sows that crushed

none (NC-sows). Locomotion behaviour traits were analysed to frequency, duration and

manner.

The relationship of crushing piglets to posture patterns of sows was investigated in chapter

two. Definite traits of sows positions (‘lying–down’, ‘standing-up’ behaviour), posture

changes, speed, manner and frequencies of movements were analysed. These traits were

calculated according to the difference between NC-sows and C-sows. Results revealed that

prepartum, NC-sows performed more restlessness while performing movements such as

92

‘standing’ or ‘sitting’. Primiparous C-sows were less ‘active’ than primiparous NC-sows. NC-

sows showed a longer duration of ‘nest-building’ behaviour per hour as well as higher

frequencies of ‘nest-building’ behaviour per hour before farrowing. Post partum ‘rolling

movements’ were shown more often in primiparous C-sows. Additionally, C-sows preferred

‘ventral recumbency’ within ‘rolling movements’ and as the final position of ‘lying-down’

behaviour. NC-sows performed ‘lateral recumbency’ more often and much longer as the final

position of ‘lying-down’ behaviour. Furthermore, especially multiparous C-sows’ bouts of

‘sitting’ behaviour were much longer than those of multiparous NC-sows. These results

suggested that different behavioural patterns, especially ‘nest-building’ behaviour prepartum

and ‘ventral-’ or ‘lateral recumbence’ post partum, are possibly useful to characterize good

maternal abilities of sows to minimise crushing piglets.

In chapter three, traits of ‘pre-lying’ behaviour of sows were analysed in relationship to

crushing piglets, as well as the times of ‘resting-activity’ cycles of the offspring and their

location with regard to the sow. The postural behavioural traits of sows and elements of ‘pre-

lying’ behaviour were analysed according to frequencies, duration, manner and combination

of other positions (e.g. ‘nosing’ and ‘looking around’ before ‘lying-down’). These traits were

calculated according to the difference between NC-sows (NC-piglets) and C-sows (C-piglets).

Results revealed post partum, primiparous NC-sows performed ‘sniffing’ as an element of

‘pre-lying’ behaviour with longer durations and significantly more often than primiparous C-

sows, especially before ‘kneeling on front legs’ followed by ‘lateral recumbent’. Furthermore,

multiparous NC-sows performed the trait ‘looking around’, followed by ‘lying-down’ with

‘kneeling on front legs’ more frequently than multiparous C-sows. Additionally, the NC-sows

‘looked’ more often towards the piglet nest site. The trait ‘nosing’ was performed by

primiparous NC-sows more often than by primiparous C-sows. The trait ‘looking around’,

followed by ‘nosing’, was performed more frequently by NC-sows than by C-sows. However,

the duration of ‘sleeping’ and the ‘activity’ behaviour beginning and ending at the mammary

gland were significantly longer in C-piglets. This study suggested that traits of ‘pre-lying’

behaviour of NC-sows and C-sows were performed differently, showing large variations in

the way the piglets’ attention was demanded before the sow finally lay down. Therefore

‘sniffing’, ‘nosing’ and ‘looking around’ as components of ‘pre-lying’ behaviour represent

possibly useful traits to determine the maternal responsiveness of sows.

93

Different behavioural traits of posture patterns of sows were analysed in combination with

several behaviour tests in chapter four. The postural behavioural traits were assessed

according to duration and frequencies of positions and analysed separately pre- and post

partum. In three different behaviour tests (SEPD1, SEP21, SCREAM), the sows’ maximum

reaction was evaluated and classified into test scores from score 1 (no reaction) to score 5

(very strong reaction). With regard to different behavioural traits, results indicated

heterogeneous correlations in different behavioural tests. In SEPD1, sows with a high test

score showed tendentially more often behavioural patterns, expect of bouts of ‘resting’

behaviour. Positive correlations of ‘activity’ behaviour and ‘nest-building’ behaviour

prepartum were found in sows’ reaction in SEPD21. Post partum ‘resting’ behaviour in

general was positively correlated as well as ‘nosing’ behaviour in SEPD21. Furthermore, a

high test score in SCREAM was positively correlated with durations and frequencies of

different behavioural traits, expect of ‘resting’ behaviour in general prepartum and ‘nosing’

behaviour post partum. These results revealed that behavioural tests heterogeneously

correlated with posture patterns of sows. Thus, it is difficult to determine maternal behaviour,

expressed by behavioural traits, via behavioural tests.

Differences between the traits to characterise the maternal behaviour of sows with regard to

piglet crushing exist, in particular in locomotory behavioural patterns. These differences

could be used in further research as targets in genetic or environmental approaches to improve

maternal behaviour in sows and to reduce the pre-weaning mortality of piglets.

94

95

ZUSAMMENFASSUNG

Die vorliegende Arbeit setzt sich mit dem maternalen Verhalten von Sauen vor, während und

nach der Geburt auseinander. Ziel ist es Verhaltensweisen zu erkennen, die im

Zusammenhang mit Ferkelverlusten aufgrund von Erdrückungen stehen. Dazu werden die

Bewegungsmuster der Sauen sowie die Aktivität der Ferkel analysiert. Darüber hinaus wird

das Bewegungsverhalten der Sauen mit denen im Verhaltenstest gezeigten Reaktionen

verglichen.

Das erste Kapitel umfasst eine Literaturübersicht zum Nestbauverhalten von Sauen. Diese

Eigenschaft ist von großer Bedeutung, besonders in Hinblick auf die Fortpflanzungsfähigkeit

der Sau und dient der Charakterisierung der Muttereigenschaften. Ziel des Nestbauens ist es,

den Ferkeln einen Platz zum Schutz zu bieten. Im Laufe der Domestikation haben die Tiere

dieses angeborene Verhalten nicht verloren und zeigen zumindest einzelne Elemente auch

heute noch vor der Geburt der Ferkel sofern ausreichend Platz und Material vorhanden sind.

Bei konventionell gehaltenen Sauen sind diese Möglichkeiten eingeschränkt. Trotzdem sollte

den Sauen die Gelegenheit zum Ausüben des Nestbauverhaltens gegeben werden, da es einen

Teil ihres natürlichen Verhaltensmusters ausmacht. Im Hinblick auf die steigenden

Anforderungen bezüglich des Tierschutzes und bevorstehende Gesetzesänderungen in der

Schweinehaltung, werden mögliche Konsequenzen für die unterschiedliche Haltungssysteme

diskutiert.

Den Analysen der folgenden Kapiteln liegt ausgewertetes Videomaterial zugrunde. Die

Aufzeichnungen wurden auf einem Basiszuchtbetrieb mit dem Zuchtprogramm ‚Hülsenberger

Zuchtschweine’ innerhalb eines Jahres erhoben. Das Bewegungsverhalten der Sauen wurde

mit Hilfe von Videokameras zwölf Stunden ante partum bis zur 48. Stunde post partum

aufgezeichnet. Insgesamt wurden auf diese Weise 438 Reinzuchtwürfe der Deutschen

Landrasse (n = 386) erfasst. Um den Arbeitsaufwand bezüglich der Auswertung zu senken,

wurden aus der Grundgesamtheit 20 Sauen ohne Erdrückungsverluste (NC-Sauen) sowie 20

Sauen, die mindestens ein Ferkel erdrückt haben (C-Sauen) ausgesucht. Während die

Auswahl der NC-Tiere zufällig erfolgte, wurden die C-Sauen so ausgewählt, dass sie

hinsichtlich der Wurfnummer, der Leistung (LGF) und der Saison mit den NC-Sauen

übereinstimmen. Das Bewegungsverhalten dieser Passer-Paarungen wurde anschließend

hinsichtlich der Dauer, Häufigkeit, sowie der Art und Weise der Ausführungen ausgewertet.

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Auf die Beziehungen zwischen erdrückten Ferkeln und den Bewegungsmustern der Sauen

wird im zweiten Kapitel eingegangen. Dies erfolgt durch die Analyse definierter Merkmale

der Sauen in bestimmten Positionen, wie dem Verhalten beim Ablegen oder Aufstehen.

Darüber hinaus werden die Bewegungsänderungen, die Schnelligkeit, die Art und Weise

sowie die Häufigkeiten der Bewegungen berücksichtigt. Die Auswertung erfolgt über die

Differenzbildung zwischen den einzelnen Passer-Paarungen bezüglich der aufgezählten

Merkmale.

Die Ergebnisse zeigen, dass die NC-Sauen vor der Geburt unruhiger sind. Dies wird

insbesondere durch ein stärker ausgeprägtes Steh- und Sitzverhalten deutlich. Des Weiteren

ist bei NC-Sauen das Nestbauverhalten vor der Geburt ausgeprägter und von längerer Dauer.

Die C-Jungsauen weisen im Vergleich zu den NC-Jungsauen weniger Aktivität auf. Nach der

Geburt zeigen C-Jungsauen mehr Rollbewegungen als NC-Jungsauen. Zudem präferieren sie

die Bauchseitenlage innerhalb der Rollbewegungen und als Endposition beim Ablegen. Im

Gegensatz dazu bevorzugen NC-Sauen häufiger die Seitenlage als Endposition vom Ablegen

und verbleiben länger in dieser Position.

Die Ergebnisse weisen auf unterschiedliche Verhaltensmuster der Tiere hin. Besonders im

Nestbauverhalten vor der Geburt und im Liegeverhalten nach der Geburt (Bauchseiten- oder

Seitenlage) sind Differenzen zu erkennen. Diese Merkmale können zur Beschreibung guter

Muttereigenschaften herangezogen werden, um so Ferkelverluste durch Erdrücken zu

minimieren.

Im dritten Kapitel werden Eigenschaften untersucht, die die Sauen direkt vor dem Ablegen

zeigten. Diese Merkmale werden in Bezug auf die erdrückten Ferkel, deren Schlaf-Wach-

Rhythmus und die Lokalisation zur Sau analysiert. Die Bewegungsmerkmale der Sau und die

Merkmale direkt vor dem Ablegen werden hinsichtlich ihrer Häufigkeit, der Dauer sowie der

Art und Weise betrachtet. Ferner werden auch Kombinationen dieser Verhaltensmerkmale

berücksichtigt, wie z. B. ‚Rüsseln’ und ‚Umsehen’ vor dem Ablegen.

Die Analysen erfolgen, wie in Kapitel zwei, jeweils mit der Differenzberechnung der

entsprechenden Merkmale zwischen den NC-Sauen (bzw. NC-Ferkel) und den C-Sauen (bzw.

C-Ferkel). Die Ergebnisse zeigen für den Zeitraum nach der Geburt, dass die NC-Sauen das

Verhaltenselement ‚Schnüffeln’ direkt vor dem Ablegen länger und wesentlich häufiger

ausführen als C-Sauen. Dieser Unterschied im Verhalten wird bei den Jungsauen besonders

deutlich und zeigt sich vor allem, wenn dem Ablegen ‚auf dem Karpalgelenk’ die ‚Seitenlage’

folgt. Des Weiteren kann festgestellt werden, dass sich ältere NC-Sauen, im Vergleich zu

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ihren Passern, häufiger umschauen vor dem ‚Ablegen auf das Karpalgelenk’ und auch

vermehrt in Richtung Ferkelnest blicken. Im Gegensatz dazu kann die Merkmalskombination

‚Umsehen’ gefolgt von ‚Rüsseln’ häufiger bei den C-Sauen beobachtet werden.

Die Dauer der Schlafzeit und der Aktivitätszeit der Ferkel direkt am Gesäuge der Sau ist bei

den C-Ferkeln länger als bei den NC-Ferkeln. Zwischen NC-Sauen und deren Passern

bestehen unterschiedliche Ausprägungen im Einfordern der Aufmerksamkeit der Ferkel vor

dem Ablegen. Daher sind ‚Schnüffeln’, ‚Rüsseln’ und ‚Umsehen’ als bedeutende

Verhaltenskomponenten vor dem Ablegen einzuordnen und können möglicherweise sinnvoll

eingesetzt werden, um die mütterliche Fürsorge genauer zu definieren.

Im Kapitel vier werden die Bewegungsmerkmale der Sauen im Zusammenhang mit

unterschiedlichen Verhaltenstests betrachtet. Dazu werden die Merkmale hinsichtlich ihrer

Häufigkeit und Dauer innerhalb einer Position separat für den Zeitraum vor und nach der

Geburt analysiert. In den drei durchgeführten Verhaltenstests wurden Reaktionen der Sauen in

unterschiedliche Situationen provoziert: beim Separieren der Ferkel von der Sau innerhalb der

ersten 24 Stunden nach der Geburt (Separationstest1), beim Separieren nach 21 Tagen

(Separationstest21) und beim Abspielen eines Ferkelschreies (Schreitest). Die maximal

gezeigte Reaktion der Sau wurde innerhalb einer Notenskala von 1 (keine gezeigte Reaktion)

bis 5 (sehr stark ausgeprägte Reaktion) bewertet. Die Ergebnisse zeigen unterschiedliche

Beziehungen auf zwischen den einzelnen Verhaltensmerkmalen und den Verhaltenstests.

Sauen mit höheren Reaktionsbewertungen im Separationstest1 weisen positive Beziehungen

zu Bewegungsaktivitäten vor und nach der Geburt auf, mit Ausnahme des Schlafverhaltens.

Im Separationstest21 zeigen Sauen mit einer höher bewerteten Reaktion vermehrtes

Nestbauverhalten und höhere Aktivität vor der Geburt und längeres Schlafverhalten und

häufigeres ‚Rüsseln’ mit ihren Ferkeln nach der Geburt. Im Schreitest mit hohen Noten

beurteilte Sauen zeigen tendenziell stärkere Beziehungen zum Bewegungsverhalten vor und

nach der Geburt. Insgesamt sind aber nur tendenzielle Zusammenhänge mit heterogenen

Ausprägungen zwischen den einmalig erfassten Reaktionsnoten in den Verhaltenstests und

den kontinuierlich beobachteten Bewegungsverhalten der Sauen festzustellen. Die

Verhaltenstests können daher nur bedingt als Hilfsmerkmal herangezogen werden, um gute

Muttereigenschaften zu charakterisieren.

Abschließend ist festzuhalten, dass die unterschiedlichen Merkmale eine Charakterisierung

des maternalem Verhaltens von Sauen ermöglichen. Dies gilt insbesondere für das

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Bewegungsverhalten der Sauen im Zusammenhang mit erdrückten Ferkeln. In weiteren

Forschungsprojekten könnten diese Unterschiede gezielt genutzt werden, um Ansätze weiter

zu verfolgen, die auf genetischer oder umweltbedingter Basis die Muttereigenschaften von

Sauen verbessern und die Ferkelsterblichkeit vor dem Absetzten reduzieren.

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DANKSAGUNG

An dieser Stelle möchte ich den Personen danken, die zum Gelingen dieser Arbeit beigetragen

haben.

Mein aufrichtiger Dank gilt Herrn Prof. Dr. Joachim Krieter für die Überlassung des Themas,

die wissenschaftliche Betreuung und die gewährten Freiräume bei der Anfertigung dieser

Dissertation. Zudem möchte ich mich für die Möglichkeiten bedanken meine Ergebnisse auf

Tagungen im In- und Ausland präsentieren zu können.

Für die Übernahme des Koreferates danke ich Herrn Prof. Dr. Edgar Schallenberger.

Das Projekt wurde ermöglicht durch die finanzielle Förderung der H. Wilhelm Schaumann

Stiftung sowie der Innovationsstiftung Schleswig-Holstein, bei denen ich mich ganz herzlich

bedanken möchte.

Für die Datenbereitstellung möchte ich mich bei Herrn Dr. Ulrich Presuhn (farm concepts)

bedanken sowie bei Frau Dr. Barbara Hellbrügge für ihre Hilfsbereitschaft und Ratschläge zu

den Datenaufnahmen.

Für die vielen Anregungen und Hilfen in der statistischen Auswertung möchte ich mich ganz

besonders bei Herrn Dr. Eckhard Stamer bedanken.

Ein riesiges Dankeschön gilt Frau Dr. Nicole Kemper. Die freundschaftliche Unterstützung

mit interessanten Diskussionen und ihre Hilfsbereitschaft, weltweit und rund um die Uhr mit

ständiger Bereitschaft zum Korrekturlesen, hat mir zur Fertigstellung dieser Arbeit sehr viel

Durchhaltevermögen und Kraft gegeben.

Für die schöne Zeit am Institut mit dem freundschaftlichen und guten Arbeitsklima möchte

ich mich bei allen Kolleginnen und Kollegen bedanken, besonders bei den aktuellen und

ehemaligen ‚Containermitbewohnern'. Hierbei möchte ich der ehemaligen W-Fraktion 'Imke

und Tanja' einen ganz herzlichen Dank aussprechen - für das ständig offene Ohr und für die

moralische Unterstützung auch vor und nach der Arbeitzeit. Des Weiteren möchte ich Teide

für die ständige Hilfsbereitschaft mit der garantierten Lösung für kleinste technische

Probleme danken, sowie Susanne, Andrea und Gesche für eure vielen netten Gespräche auch

außerhalb des Containers.

Ein großes Dankeschön geht an meine Freunde auch außerhalb des Instituts für das

entgegengebrachte Verständnis (v. a. Sonja, Maren, Miriam und Antje) und die ‚laufende'

Unterstützung (Jens) während der gesamten Zeit.

Mein größter Dank gilt meiner Mutter, Norbert und Hinni, für den uneingeschränkten

Glauben an mich und die damit verbundene ständige Unterstützung – Danke!

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101

LEBENSLAUF

Name: Diane Wischner

Geburtstag: 25. April 1980

Geburtsort: Ibbenbüren

Staatsangehörigkeit: deutsch

Familienstand: ledig

Schulische Ausbildung:

1986 – 1990 Ludgerus Grundschule, Hörstel 1990 – 1999 Goethe-Gymnasium, Ibbenbüren

Abschluss: Allgemeine Hochschulreife 1999 – 2000 einjährige Höhere Handelsschule für Abiturienten, Ibbenbüren

Studium:

2000 – 2001 Studium der Rechtswissenschaften, Universität Osnabrück 2001 – 2004 Studium der Agrarwissenschaften, Christian-Albrechts-

Universität zu Kiel, Fachrichtung: Nutztierwissenschaften Abschluss: Bachelor of Science

2004 – 2005 Studium der Agrarwissenschaften, Christian-Albrechts-Universität zu Kiel, Fachrichtung: Nutztierwissenschaften

Abschluss: Master of Science

Landwirtschaftliche Praktika:

08/2002 – 09/2002 Bundesforschungsanstalt für Landwirtschaft, Institut für Tierzucht, Mariensee

08/2003 – 09/2003 Heereman’sche Verwaltung Rentei Surenburg, Hörstel-Riesenbeck

08/2004 – 09/2004 Landwirtschaftskammer Schleswig-Holstein, Abteilung Tierhaltung und Tierzucht, LPA, Achterwehr

08/2005 – 10/2005 Landwirtschaftlicher Betrieb, Verden

Berufliche Tätigkeit:

seit November 2005 Wissenschaftliche Mitarbeiterin am Institut für Tierzucht und Tierhaltung der Christian-Albrechts-Universität zu Kiel bei Herrn Prof. Dr. J. Krieter