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Phenotyping intake rate in dairy goats, a repeatable trait which can be measured automatically

Sylvie Giger-Reverdin, Christine Duvaux-Ponter & Nicolas C Friggens

Modélisation Systémique Appliquée aux Ruminants (Systemic modelling applied to ruminants)

Inra, AgroParisTech, Université Paris-Saclay, France

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Introduction

High producing animals are fed with a high proportion of concentrates

They can suffer from acidosis

Intake rate is a key-factor to explain the inter-individual variation in the evolution of rumen pH (occurrence of acidosis)

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Aim of the work: To develop repeatable, pertinent and easy to measure criteria to evaluate this trait in dairy goats

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Experimental design

35 dairy goats born in 2011

1 TMR diet ad libitum: 20 % Concentrate 20 % Meadow hay 30 % Dehydrated lucerne 30 % Pressed sugar beet pulp silage

Automatic measurement of feed intake (2 min.)

3 periods (3 or 4 days/period) • P1: 1st lactation • P2: 2nd gestation & end of 1st lactation • P3: 2nd lactation

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P3: 2nd lactation P1: 1st lactation

P2: 2nd gestation and end 1st lactation

4 days/period

0

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0 120 240 360 480 600 720 840 960 1080 1200 1320Cu

mu

lati

ve d

ry m

atte

r in

take

(g/

kg B

W)

Time after the afternoon feeding (min)

Evolution of daily intake

0

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0 120 240 360 480 600 720 840 960 1080 1200 1320

Cu

mu

lati

ve d

ry m

atte

r in

take

(g/

kg B

W)

Time after afternoon feeding (min)

P3 & P1 P2

Proportions of feed eaten post afternoon feeding

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

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0 120 240 360 480 600 720 840

Time after the afternoon feeding (min)

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0 120 240 360 480 600 720 840

Time after the afternoon feeding (min)

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Two Phenotypes measured Q90: DMI consumed by 90 min post afternoon feed allowance (g/kg BW) P90: Ratio Q90/DMI in 15 hours

960840720600480360240180120600

35

30

25

20

15

10

5

0

Time after feeding (min)

DM

I (g

/kg

BW

)

Goat A

Goat B

Dry matter intake evolution (pm Feed allowance )

P90 = 0.90

P90 = 0.38

(Giger-Reverdin et al., 2009)

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Factors of variation of the phenotypes: Evolution between periods and between-goat variability

All Periods P1 (1st Lactation)

P2 (2nd gestation)

P3 (2nd lactation)

N observations 105 35 35 35

Q90 (g/kg BW) 16.1 ± 3.63 14.6a ± 3.36 14.8a ± 2.83 18.8b ± 3.03

P90 0.499 ± 0.1115 0.416a ± 0.1055 0.524b ± 0.0972 0.556b ± 0.0796

Increase in Q90 at P3 Increase in P90 as goats are getting older Significant between animals variability

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Factors of variation of the phenotypes: Across animals, average repeatability (standard deviation/goat/period)

All Periods P1 (1st Lactation)

P2 (2nd gestation)

P3 (2nd lactation)

N observations 105 35 35 35

Q90 (g/kg BW) 1.56 ± 0.896 2.05a 1.33b 1.29b

P90 0.0422 ± 0.02321 0.0520a 0.0406a,b 0.0343b

Q90 and P90 are more repeatable for each goat within a period as goats are getting older No goat effect

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Across animals, average repeatability

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20

15

10

201510

25

20

15

201510

Q90_1

Q90_2

Q90_3

11044

11048

11055

11056

11062

11064

11066

11069

11070

11071

11009

11072

11073

11074

11079

11084

11090

11092

11093

11096

11097

11014

11100

11107

11109

11110

11111

11112

11015

11016

11024

11025

11035

11036

11040

Goat

Between-periods correlation for Q90

0.61**

0.42*0.28

0.60

0.45

0.30

0.60.40.2

0.7

0.6

0.5

0.600.450.30

P90_1

P90_2

P90_3

11044

11048

11055

11056

11062

11064

11066

11069

11070

11071

11009

11072

11073

11074

11079

11084

11090

11092

11093

11096

11097

11014

11100

11107

11109

11110

11111

11112

11015

11016

11024

11025

11035

11036

11040

Goat

Between periods correlation for P90

0.54**

0.63** 0.38*

P90 is more repeatable than Q90 P90 is a characteristic of the feeding behaviour of the goat

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Conclusion and practical implications

High intra-period individual repeatability High between-period repeatability

Characterisation of the feeding behaviour during the 1st lactation Adjustment of feeding in the following lactations to decrease the

occurrence of acidosis

Possibility to phenotype goats on intake rate in precision livestock farming

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Thank you for your attention