How long ewes are pregnant

Gestation period for sheep The average gestation period for sheep is around five months, although this may be a little shorter in some cases.

How long do sheep breed for? During her lifetime, a ewe can produce lambs typically from about a year of age up to ten years. Feed Flushing. How fast do lambs grow? Do you need a milk replacer? It appears that ewes being bred on an accelerated lambing schedule may have lower conception rates in season. Lunstra and Christenson synchronized ewes with progestogen sponges for 16 days and injected them with PMSG on day The results for the two groups were not statistically different, showing that synchronization worked as well mid anestrus as in late anestrus Table 5.

Conception rates were highest among ewes that exhibited estrus within 72 hours of the PMSG injection. In the same study, ovulations were actually counted at hours after the onset of estrus. This showed that The authors speculated that when ewes are treated to breed out of season, there may be greater asynchrony between the time of heat, LH surge and ovulation, particularly in those ewes that don't show heat within 72 hours of PMSG injection.

This could be one reason for the difference in the number of ewes in heat and ewes actually lambing. Target conception rates are calculated based on either how many ewes produce lambs or how many ewes are pregnant at scanning. Table 6 targets are based on how many ewes produce lambs. Many factors can affect target conception rates. These will differ depending on the age of the ewes, lambing interval, breed and production system.

Source: Notter Source: Lunstra and Christenson Each of these factors can have a significant effect on conception rate; in some cases, a combination of factors causes conception problems. Out of season, every factor must be managed well in order to have a successful outcome.

If conception rates are poorer than expected, review all management factors, including ram management, health, nutrition, lambing interval, age, genetics, stress and environmental factors such as heat. Good conception rates are essential for the profitability of a sheep farm. High rates of fertility can and should be achieved with an annual lambing system when breeding in season. Breeding out of season most often results in a wide range of conception percentages.

Out of season, manage all factors strictly to achieve satisfactory conception results. If conception rates are not high, consider and review the many factors that influence the number of ewes lambing and the number of lambs born, including age, breed, lambing interval, health, nutrition, stress and the ability of the ram.

Sheep Production Handbook. Casas, E. Reproduction of F1 ewes in fall mating seasons. J Anim Sci Reproduction of F1 ewes in spring mating seasons. Castonguay, F. La reproduction chez les ovins. Hafez, B. Reproduction in farm animals. Rapid rebreeding of winter- and spring-lambing ewes is essential if ewes are to lamb more than once per year, but fertility of lactating ewes is often low and early weaning of lambs may be undesirable in forage-based production systems. Selection to improve fertility in spring matings has been successful and led to development of ewes with a reduced seasonal anestrus.

Potential for rapid rebreeding of lactating out-of-season breeding OOS ewes was tested in three studies. In Experiment 1, effects of short-term lamb removal on rebreeding was evaluated over 2 years using 71 January-lambing OOS ewes. Parturition Just born. Polypays: less seasonal. Cull ewes that prolapse. Trim hooves prior to breeding. Ewe lamb in heat Hampshire ewes being fed. Barbados Blackbelly ewes Laparoscopic AI. Trans-cervical AI.

Ewe with quads. Replacement ewe lamb Whiteface ewes. Reproductive rate is defined as the number of live lambs born per ewe exposed for breeding. Optimal reproductive rates are essential to profitable sheep production. Optimal reproductive rate varies by farm, production system, and geographic area. Puberty sexual maturity Puberty is when a ewe reaches sexual maturity and exhibits estrus heat for the first time.

The age of puberty is influenced by breed, genetics, size weight , nutrition, and season of birth. Most ewe lambs reach puberty between 5 and 12 months of age. Ewe lambs will tend to reach puberty their first fall. For this reason, spring-born ewe lambs tend to exhibit puberty earlier than fall-born ewe lambs. Lambs born early in the season reach puberty earlier than those born later in the season, due to their increased age and body weight.

One way to select for early puberty is to expose ewe lambs for breeding and scan them for pregancy, culling any ewe lambs which fail to become pregnant.

High levels of feed pre and post-weaning reduce the age at puberty. Single lambs cycle at a younger age than twin and triplet-born ewe lambs, due to their size advantage. Ewe lambs from fine-wool, coarse wool, and late-maturing medium-wool breeds reach puberty later than many of the meat Suffolk, Dorset, etc. Croix, and Barbados Blackbelly breeds.

Finnsheep and Romanov ewe lambs and their crosses reach puberty at an earlier age than most breeds. Crossbred ewe lambs cycle at a younger age than purebred ewe lambs. The estrus or heat cycle Reproduction in non-human mammals is regulated by an estrus cycle. In sheep, the length of the estrus cycle ranges from 13 to 19 days and averages 17 days. There are four phases to the estrous cycle: proestrus, estrus, metestrus, and diestrus. Estrus is the period of time when the ewe is receptive to the ram and will stand for mating.

It lasts approximately 24 to 36 hours. Ovulation release of eggs by the ovary occurs in mid to late-estrus. Metaestrus begins with the cessation of estrus and lasts for about 3 days. Primarily it is the period of the formation of corpus luteum CL.

The corpus luteum produces progesterone and maintains pregnancy in the ewe. Diestrus is the period of the estrus cycle when the CL is fully functional. Proestrus begins with the regression of the CL and drop in progesterone and extends to the start of estrus. Rapid follicular growth is occuring during this period. It usually extends from day 4 to day of the cycle. Anestrus refers to a state where the normal cycle stops. Estrous cycles are usually affected by season.

The number of hours daily that light enters the eye of the animal affects the brain, which governs the release of certain precursors and hormones. Most sheep are seasonally polyestrus and short-day breeders. They will begin to exhibit estrus when length of day begins decreasing.