Control means for estrous cycle control in sheep

Mourad Rekik

EIAR-DBARC-ICARDA-ILRI (LIVES)-FAO Training on Reproduction in Sheep and Goat, Debre Berhan,

Ethiopia, 13-15 October 2014

Control Means

Introduction

Synchronisation of oestrus and induction of

ovulation

Natural method

Hormonal treatments

Improvement of litter size

• Long seasonal anoestrus : 2-6 mois

• Pregnancy: 5 months• Postpartum anoestrus: 1-3

months• An inherent low prolificacy

Physiological causes of reduced reproductive efficiency in sheep and goats

In most production systems, sheep and goats give birth once a year, produce single litters and the production is seasonal.

Improvement of fertility

Breeding season

Anoestrous season

Synchronisation

Induction

Synchronisation

Control over the events of the oestrous cycle

Mating Synchronisation Lambing Compactness

The best mating time

(Maximise fertility)

Nutritional requirements

and provision from cheap natural feed

According to the market

requirements and the

consumer demand

CHOOSEADJUST PRODUCE

Olfactory senses

hypothalamus

Pituitary gland ovary

Male stimuli (Pheromones)

Central nervous system Reproductive tract

LH

FSH

GnRH

Natural method: The «male effect»

How it works

Types of Ovulatory and Estrous Cycles of Ewes in Response to Ram Introduction.

Variation Factors

• Age : Maiden/Adults (75 % vs 95 %) • Breed : Temperate/Meridional• Season

– Stage of seasonal anoestrous– Association seasonal and postpartum

anoestrous• Body condition : Females in depressed BC do

not respond• Male sexual aggressiveness: sex ratio and

maturity

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 300

1

2

3

4

5

6

7

8

Percent of mated ewes in 5 flocks (6 years, 5894 observations; anoestrous season)

Jours

(%)

67% of females

Rekik, 2011

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 260

2

4

6

8

10

12

14

16

Distribution des 1ers oestrus dans le troupeau expérimental

Jour

Pour

cent

age

des f

emel

les e

n oe

stru

s (%

)

11

Synchronisation using the ram effect and a single injection of 20 mg of progesterone in

oil

APPEARANCE OF OESTRUS

0

10

20

30

40

50

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

EM

MALE EFFECT IN GOATS

P4

MALE EFFECT

0

10

20

30

40

50

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

EM

EMP

MALE EFFECT

Days 0 9 50 hours

PGF2

 

TREATMENT MALE EFFECT + P4 PROGESTAGENS PROSTAGLANDINS

FEMALES 1584 600

FERTILITY 64,6% 46,8%

A.I.P4

MALE EFFECT

Hormonal Methods: FGA+eCG in sheep

1

5

FGA plasma levels(ng/ml)

Sponges left in12 - 14 days

eCG

LH

Oestradiol

Ovulation

Corpus luteum(Progesterone)

Time+ 48 h + 60 h

Sponges in

OESTRUS

Controlled mating

Sponges out 2 days

Not before 150 days postpartum

11 days (± 1)

eCG

Sponges 45 mg FGA

In Out Natural mating or AI 43-45 hours

After withdrawal of sponges

Short protocol for synchronisation of oestrus in goats

PgF2

48h prior to sponges withdrawal

250 to 600 IU

98 % of goats are in oestrus between 24 and 72 hours after withdrawal of sponges

ALTERATIONS CAUSED BY PROGESTATIVETREATMENTS

LACK OF RESPONSE

LACK OF SYNCHRONIZATION

ALTERATIONS IN THE OVULATION

ALTERATION IN MOBILITY AND VIABILITY OF SPERM

0

0,5

1

1,5

2

2,5

3

-2,5 -2 -1,5 -1 -0,5 0

Días respecto celo

Est

rad

iol

(pg

/ml)

ALTERATIONS CAUSED BY PROGESTATIVETREATMENTS

Days to oestrus

26

27

28

29

30

31

32

33

34

0 1 2 3 4 5

Inte

rval

sp

on

ge

wit

hd

raw

al-

oes

tru

s (h

)

Number of treatments

Panel A

0

10

20

30

40

50

60

70

80

20 40 60 80

Fer

tili

ty (%

)

Interval sponge withdrawal-oestrus (h)

No oestrus

Panel B

Alterations caused by eCG:

Relationship between the interval withdrawal of sponges-oestrus and the number of eCG treatments (Panel A) and

between the same interval and fertility of the does (Panel B) (Redrawn from Chemineau et al., 1999).

20

40

60

80

100

120

140

160

180

0 200 300 400

% c

on

cep

tio

n r

ate

or

pro

lifi

cacy

Dose of eCG (IU)

Conception rate

Prolificacy

The effect of increasing doses of eCG on conception rate and prolificacy at the induced oestrus of local Tunisian female goats (N. Lassoued and M. Rekik, 2010, unpublished results)

MELATONIN

Utilisation Protocol

7 d. 42 to 49d. (6 to 7 weeks)

Implant insertion

Isolation of rams

Ram Introduction

Mating

150 d+/- 5 d

After ramintroduction

3 implantsram

1 implantEwe/ewe lamb

Lambing

Awassi breed- Syria

84

12

84

16

92

28

84

40

0

10

20

30

40

50

60

70

80

90

100

MélovineControl

Fertility %

Implantin : 9 April 23 April 7 May

Mélovine (CEVA®)

26 March

Mating : May End MayJune

mid Junemid July

end JuneJuly

Maiden ewes during anoestrus

Breed Treatment Females lambing (% fertility)

Lambs born(% prolificacy)

Noire de Thibar

Mélovine: 70 49 (70%) 52 (106%)

Control: 70 34 (48%) 34 (100%)

Sicilo-Sarde

Mélovine: 60 30 (50%) 30 (100%)

Control: 60 23 (38%) 23 (100%)

+ 22%

+ 12%

Rekik, 2010

Estrus synchronisation with Prostaglandin (PGF2α)

I: intramuscular injection of 125 mg of Cloprosterol (Estrumate®)

1st I 2nd I

10- 14 days 36 to 48 h after the second injection

Estrus

• Cycling ewes• does not interfere with subsequent cyclicity of sheep in 90% of cases : "natural“estrus

Estrus synchronisation with Ovsynch Protocol

7 days 48 h 16-24 h

GnRH (Receptal /Fertagyl 2.5 ml)

PGF2α

(Estrumate 2 ml)

GnRH (Receptal /Fertagyl 2.5 ml)

G P G

Fixed time AI

Ovulate the dominant follicleIntiate the new follicular wave

Induce luteolysis

Induce ovulation of new dominant follicle

Synchronisation of estrus

Synchronisation of ovulation

Improvement of prolificacy

• Possible but difficult

• Low genetic progress: low heritability of

the trait

• Indrect selection on prolificacy: ovulation

rate,

Embryo mortality

• Several generations: 20

• Tunisia: W strain of th Barbarine breed:

160% vs 120% for ordinary Barbarine

Selection

h2 <0,1

Fast way to improve litter size Heterosis: 3% for prolificacy

QFO D ’Man X QFO

Nb. 36 31LW (Kg) 45,7+5,7 40,5+5,9

Fertility(%) 77,7 90,3Prolificacy(%) 1,14+0,351,43+0,50

+ 20%

Crossbreeding with prolific breeds

Mating

2 weeks

prior

2 weeks

after

Short feeding supplementation

Distribution of concentrates (60% above maintenance)

Ovulation

rate

Embryo losses

Nutritional method: Flushing

Between 20 and 40 % in terms of lambs born

Hormonal methods : eCG

Response of Noire de Thibar ewes in terms of ovulation rate to increasing doses of eCG

eCG dose (IU) Ovulation rate

0 1.41

400 1.47

600 1.76

800 1.63

1000 1.76

• Synchronisation of ovulations and oestrus • Variable effect according to

a. doses (High doses litter size)

b. breed

AD-HSA AD-HSA

Active

1st immunisation

3 weeks

2nd immunisation

3 weeks

Mating

Passive

Injection immune serum

Mating

Antibodies

Hormonal method : Immunisation against androstenedione (during breeding season)

Expected results

• Increase of ovulation rate from 0,37 to 1,17

(active immunisation, Land et al., 1982)

• Less variability in response

• Most increase is represented by twins

• Effective on non prolific breeds

• No adverse effects on immunised dams

• Reduced labor

Immunisation against androstenedione

Conclusions

• Several methods There is no best method

• Options are dependent upon:

• Physiological stage

• Potential of the production system

• Objectives, know how and financial asset of farmers

• Products availability and effectiveness

Thank you