Domestic sheep reproduction

[5] Freemartins, female bovines that are behaviorally masculine and lacking functioning ovaries, are commonly associated with cattle, but do occur to some extent in sheep.

Rams, especially unfamiliar ones, will also fight outside the breeding period to establish dominance; they can kill one another if allowed to mix freely.

[1] During the rut, even normally friendly rams may become aggressive towards humans due to increases in their hormone levels.

The crayon in the marking harness can be changed during the breeding cycle to allow for lambing date predictions for each ewe.

Vaginal, uterine, or anal prolapse may also occur, in which case either stitching or a physical retainer can be used to hold the orifice in if the problem persists.

[7] Usually ewes that experience serious issues while lambing, such as prolapse, will be discarded from the flock to avoid further complications in upcoming years.

[12] These programs became more commonplace in the United States during the 2000s as the number of veterinarians qualified to perform these types of procedures with proficiency have grown.

Unlike cattle or goats, which have straight cervices that can be vaginally inseminated, ewes have a curved cervix that is more difficult to access.

Historically, vaginal insemination of sheep only produced 40-60% success rates, and was thus called a "shot in the dark" (SID).

Fresh semen is recognized as the method of choice as it lives longer and yields higher conception rates.

Producers owning prize-winning rams have found this to be a good avenue to leverage the accolades of their most famous animals.

The primary industry to utilize this technology in the United States is club lamb breeders and exhibitors.

One of the main reasons for the conditions of low lambing percentages seen in a flock is due to mineral and vitamin deficiencies.

Normal labour may take one to several hours, depending on how many lambs are present, the age of the ewe, and her physical and nutritional condition prior to the birth.

[8] These pens, which are generally two to eight feet (0.6 to 2.4 m) in length and width, are designed to aid both careful observation of ewes and to cement the bond between them and their lambs.

[7] However, it is a myth that sheep cannot lamb without human assistance; many ewes give birth directly in pasture without aid.

A lamb may present in the normal fashion (with both legs and head forward), but may be too large to slide out of the birth canal.

[27] After the birth, ewes ideally break the amniotic sac (if it is not broken during labour), and begin licking to clean the lamb.

[1] Lambs that are breathing and healthy at this point begin trying to stand, and ideally do so between a half and full hour, with help from the mother.

Once trimmed, a small container (such as a film canister) of iodine is held against the lamb's belly over the remainder of the cord to prevent infection.

[1] Ram lambs not intended for breeding are castrated, though some shepherds choose to avoid the procedure for ethical, economic or practical reasons.

An elastrator places a tight band of rubber around an area, causing it to atrophy and fall off in a number of weeks.

[30] Australian grazers, too, do not receive the financial support that governments in other countries provide to sheep breeders.

[33] Stud or specially selected rams are chosen with aid of objective measurements, genetic information and evaluation services that are now available in Australia and New Zealand.

[34][35] The choice of mating time is governed by many factors including climate, market requirements and feed availability.

On other properties the mobs are inspected by stockmen at varying intervals to stand cast ewes and deal with dystocia.

Inbreeding depression has been found for lamb birthweight, average daily weight gain from birth until two months, and litter size.

[39] In the major sheep countries of Argentina, Uruguay, Brazil, Peru and Chile, breeders are also utilizing fleece testing and performance recording schemes as a means of improving their flocks.

[41][42] Another area of research that is growing in importance is the reduction of greenhouse gas emissions, mainly methane, from livestock.

Many researchers are conducting studies to determine how manipulating sheep diets may help reduce these dangerous emissions.