REPRODUCTION PROFILES OF SHEEP

PREPARED BY NUR ARIANI BINTI DZULKARNAIN

SMALL RUMINANT PRODUCTION

1.0 INTRODUCTION• Reproduction is the propagation and

continuation of a species through a sequence of events that involves the production of hormones and the development of the reproductive system to carry out germ cell development, fertilization, pregnancy and eventually parturition.

• The female sheep is referred to as the ewe while the male sheep is called a ram.

2.0 REPRODUCTIVE SYSTEM

3.0 PUBERTY IN RAM AND EWE• Most ewe lambs will reach puberty by the

time they have developed to 50-70% of their body weight which is between 5 to 12 months of age.

• Ram reach puberty may occur as early as 5 months, however, full reproductive competence may not occur until 15 months of age.

4.0 ESTROUS CYCLE• The estrous cycle, defined as the number

of days between two consecutive periods of estrus (heat), is on average 17 days in ewes.

5.0 ESTRUS AND SIGN OF ESTRUS

• This is the phase of the estrous cycle when the ewe will be receptive to the ram.

• Complete estrus generally lasts for about 24 to 36 hours in the ewe.

5.1 ESTRUS DETECTION TECHNIQUES

Teaser ram Apron tied at the ram Crayon-marking harness

6.0 LIBIDO (SEXUAL DESIRE)• Libido is a male’s desire to mate.• The willingness to breed ewes is highly

variable among rams and can have a major impact on sheep production, especially in a single-sire mating scheme.

• This behavior is regulated by the release of testosterone, produced by specialized cells in the testes.

• Mounting and thrusting behavior, sniffing of the genital region and Flehmen reaction (curling of the upper lip of the male in response to detecting sexual readiness of the female) are well established common behaviors of normal sheep.

8.0RAM-TO-EWE RATIO• Maintaining the correct ratio of fertile rams

and ewes is important as it can affect the overall reproductive efficiency.

• The appropriate ratio is either one ram to 20–25 ewes or 3 per 100 ewes in a year-round mating.

9.0DETERMINE THE PREGNANCYa) Non-return to estrus

– Using teaser ramb) Progesterone test

– If the progesterone level is between 11‐13 nmol/l (it is between 7‐8.5 nmol/l at ewe lambs) on the 30th day after the impregnation then the probability of the pregnancy is 95%.

c) Ultrasonography– Ultrasonography examination can be done as early as

28–30 days using intra-rectal examination. – Trans-abdominal ultrasonography is done after 40 days

post-breeding.

10.0 GESTATION (PREGNANCY PERIOD)

• Gestation is the period from fertilization to delivery of the fetus.

• The average gestation length in sheep varies from 142 to 152 days.

• The average is 147 days.

11.0 PARTURITION (LAMBING)Stages Behavior of the ewe

Stage One: dilation of the cervixIs immediately before lambing (up to 12 hours).

The ewe isolates itself from the flock, seeking a solitary place; Becomes restless and uneasy; Paws and scrapes the ground, sits and stands; Stretches and strains with her neck skyward when sitting; Forces placenta, fetus, and fluids against the cervix to dilate it; The water bladder appears or has already ruptured; The ewe licks the fluid, wanders about.

Stage Two: expulsion of the fetus(es)Is typically faster and lasts about 30–45 minutes

It is accompanied by straining (contraction of abdominal muscle) The lamb normally appears front feet and nose first. At this stage, the animal is

normally lying on her side. This stage is completed by expulsion of the last lamb in case of multiple births.

Once the lamb is ejected, the dam will licks off the membrane covering of the lamb. This uncovers the mouth and nose and stimulates breathing.

Stage Three: expulsion of the placenta Expulsion of the placenta normally within 4 hours, and Involution of the uterus.

11.1 COMPLICATION OCCUR DURING PARTURITION

Fig.1: Head first with both forelegs, body right side

up.

Fig 2: Head first with one foreleg, body right side up

Fig 3: Head bent down with forelegs correct, body right

side up.

Fig 6: Hind feet first, body upside down.

Fig 4: Head thrown back with forelegs correct, body right side up.

Fig 5: Hind feet first, body right side up.

Fig 7: Breech position with rump and tail, no feet visible.

Fig 8: Head first with one foreleg, body upside down.

Fig 9: Head alone, no feet visible.

13.0 CONCLUSION• Reproduction determines several aspects of

sheep production and an understanding of reproduction is crucial in reproductive management.

• A high rate of reproductive efficiency is important for:– Perpetuation of the species,– Production of meat, milk, skin and fiber, and– Replacement of breeding stock.

14.0 REFERENCE• Abebe, G. (n.d.). Sheep and Goat Production Handbook for

Ethiopia. Reproduction of Sheep and Goat, 60-79.• Brester, G. (April 2012). International Lamb Profile. Agricultural

Marketing Resource Center.• Chemineau, P., Malpaux, B., Delgadillo, J.A., Guérin, Y., Ravault,

J.P., Thimonier, J., Pelletier, J.,. (1992.). Control of sheep and goats reproduction: use of light and melatonin. Anim. Reprod. Sci. 30, 157–184.

• Diego Gimenez, S. R. (July 2007). Reproductive Management OF Sheep and Goat. Alabama Cooperative Extension System.

• Gordon, I. (1997). Controlled Reproduction in Sheep and Goats. Wallingford, UK.: Cambridge University Press.

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