Socio-sexual cues as a proximate factor affecting reproduction behavior and physiology in sheep

Socio-sexual cues as a proximate factor affecting reproduction behavior and

physiology in sheep

Mourad Rekik

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

Ethiopia, 13-15 October 2014

Three Environmental Influences

Photoperiod

Other Pituitary Hormones

ProlactinACTH-Glucocorticoid

Somatotrophic systemThyrotrophic system

Puberty

Lactation

Nutrition

Gonads

Reproductive tractMammary glands

Sex steroids

Gonadotrophins

Socio-sexualSignals

(pheromones)

AutonomicNervousSystem

Nutrition

Socio-SexualSignals

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

Effect of peripheral induced anosmia on the response of anoestrous Merino ewes to the ram effect

Treatment N Ewes ovulating Ovulation rate

Control (no males)

14 2 (14) 1.00

Control (with males)

13 9 (69) 1.11

Anosmic*(with males)

12 8 (66) 1.38

* Anosmia was induced by irrigating the nostrils with a 5% solution of zinc sulphate

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

Mar Apr May Jun Jul Aug Sep Nov DecDec Jan FebSep Oct Nov

Breeding Season Non-breeding Season Breeding Season

% Females ovulating

100

50

0

Northern Hemisphere

Socio-sexual responses in goat and sheep

1) Breeding out of season2) Breeding postpartum3) Advancing puberty4) Synchronised pregnancies

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

Response of post-partum anoestrus ewes to the ram effect

0102030405060708090

15 25 35 45 60

Jours après mise bas% d

e fe

mel

les

qui o

vule

nt

IsoléesEffet bélier

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

PG

F2

TREATMENT MALE EFFECT + P4 PROGESTAGENS PROSTAGLANDINS

FEMALES 1584 600

FERTILITY 64,6% 46,8%

A.I.P

4

MALE EFFECT