For best results, breed them separate from older ewes. In some cases, it may be better to use rams of smaller breeds on young ewes to minimize the chance of lambing difficulties.
Sexual activity in sheep is primarily controlled by the ratio of daylight to dark. Estrus becomes more frequent as the days become shorter. In general, fertility is highest and most efficient when ewes are bred in September, October, or November; ewes bred at this time generally produce the highest percentage of multiple births.
High temperatures are detrimental to fertility, embryo survival, and fetal development. This is the biggest objection to fall lamb production.
High temperatures at breeding can reduce conception rate. Heat stress during gestation impairs fetal development and can cause lambs to be significantly smaller at birth. The introduction of a ram near the end of the anestrous period appears to psychologically stimulate ewes. It brings about earlier ovulation and estrual activity. The ram can be either fertile or surgically sterilized. Rams should be kept with the ewes for about 10 to 14 days and removed from the flock before breeding begins.
Then, at the beginning of the breeding season, rested fertile rams that are intended to sire the lamb crop can be introduced. The stimulation does not occur when rams are placed with ewes earlier, or when rams are simply left with the ewes continuously.
Nutrition has a direct bearing upon reproductive performance. Ewes kept in acceptable condition before breeding normally produce more lambs if they are flushed, or given the chance to gain weight before and during the breeding season. They can be flushed with rested pastures or by supplementation. Begin flushing three weeks before breeding and, if possible, continue through the first cycle approximately 17 days.
Flushing ewes is most effective when they are mated early in the breeding season. Since ovulation rate is near a maximum during the middle of the season, flushing at this time is not as beneficial. The results of flushing are quite variable. Sometimes, when farm flock ewes are already on a high nutrition level before the breeding season, flushing may not affect ovulation or lambing percentage.
Nutrition affects total lifetime productivity of sheep by influencing mature size. Well-developed ewes consistently have higher lamb crop percentages than smaller ewes. Fat ewes, however, are typically less fertile, do not respond to flushing, and may experience more embryonic death loss.
Ewes grazed on legume pastures, such as alfalfa and clover, may at times be less fertile. Under some conditions, the estrogen content of these legumes is related to reproductive disorders. Breeding dates may be delayed and conception rate reduced when ewes are on pastures that have a high estrogen content.
However, the estrogen content of legumes declines during the later stages of maturity. Both lambing and lactation suppress estrous cyclicity in ewes. Generally, the postpartum anestrous phase lasts through lactation, even though the uterus typically returns to normal two to three weeks after lambing. Most ewes that lamb in late winter or spring do not exhibit estrus until the following breeding season.
However, ewes that lamb in the fall usually exhibit a fertile heat four to eight weeks after lambing, or approximately two weeks after weaning. Heavy infestation of internal parasites can reduce the body condition of breeding ewes and may reduce reproductive performance. To minimize negative effects, follow a regular parasite control program and vaccination schedule.
A local veterinarian should be able to provide sufficient information to develop a flock health program. Infertile, diseased, or disinterested rams often cause poor lambing rates. The average number of ewes that can be mated to a ram are as follows: well-matured ram lambs, 15 to 30 ewes; yearlings to five-year-old rams, 25 to 50 ewes.
However, in many of the low-rainfall areas of New Mexico, the average number of ewes per ram may be 30 to 40 percent lower than these values. These rates depend upon season, temperature, sex drive, and body condition. Rams six years and older that are in good physical condition may still be suitable for pasture or hand breeding. Rams vary in their sexual behavior. Resources What is the gestation period for sheep — What to know when raising sheep.
How many lambs can sheep have each year? A ewe will produce her largest litter of lambs when she is between three and six years old. This means that lambs tend to be born in winter, so typically between August and October.
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. There are key factors to consider during pregnancy which affect the chances of successful lambing:.
Pregnancy is generally days five months. The majority of foetal growth occurs in the final 60 days; however, setting up effective nutrient transfer from the ewe to the foetus occurs with udder and placental development in the first trimester of pregnancy. Most of the wool follicle development occurs in the second and third trimesters and can be significantly affected by nutrition. Managing pregnancy in ewes.
Page last updated: Wednesday, 21 March - am. Please note: This content may be out of date and is currently under review. Figure 1 The increasing weight of the foetus is made up of placenta, udder and conceptus Source: D.
Contact information Beth Paganoni. Email Beth Paganoni. Email Danny Roberts.
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