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
Prolactin
ACTH-Glucocorticoid
Somatotrophic system
Thyrotrophic system
Nutrition
Nutrition
Puberty
Lactation
Gonadotrophins
Gonads
Sex steroids
Reproductive tract
Mammary glands
Socio-sexual
Signals
(pheromones)
Autonomic
Nervous
System
Socio-Sexual
Signals

Natural method: The «male effect»
Olfactory senses
How it works
hypothalamus
Pituitary gland
ovary
Male stimuli
(Pheromones)
Central nervous system Reproductive tract

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

Socio-sexual responses in goat and sheep
% Females ovulating
100
1) Breeding out of season
2) Breeding postpartum
3) Advancing puberty
4) Synchronised pregnancies
Breeding Season Non-breeding Season Breeding Season
Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Nov Dec
50
0
Northern Hemisphere

8
7
6
5
4
3
2
1
0
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 30
(%)
Jours
Percent of mated ewes in 5 flocks (6 years, 5894 observations;
anoestrous season)
67% of females
Rekik, 2011

Response of post-partum anoestrus ewes to
the ram effect
90
80
70
60
50
40
30
20
10
0
Jours après mise bas
15 25 35 45 60
% de femelles qui ovulent
Isolées
Effet bélier

16
14
12
10
8
6
4
2
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
Pourcentage des femelles en oestrus (%)
Jour
Distribution des 1ers oestrus dans le troupeau expérimental
11
Synchronisation using the ram effect and a
single injection of 20 mg of progesterone in
oil

MALE EFFECT IN GOATS
APPEARANCE OF OESTRUS
50
40
30
20
10
0
EM
1 2 3 4 5 6 7 8 9 10 11 12

MALE EFFECT

50
40
30
20
10
0
EM
EMP
MALE EFFECT
1 2 3 4 5 6 7 8 9 10 11 12

MALE EFFECT
Days 0 9 50 hours
A.I.
TREATMENT MALE EFFECT + P4 PROGESTAGENS
PROSTAGLANDINS
FEMALES 1584 600
FERTILITY 64,6% 46,8%