How can sheep flock reproduction rates be improved? These technical measures need to be mastered
?Strengthen the feeding and management of the sheep flock
Feeding and management requirements for breeding rams: breeding rams should maintain an upper-middle condition year-round, healthy, lively and full of energy. Being too fat or too thin is not conducive to mating. The feed should be a complete compound feed with high nutritional value, easy digestion and good palatability. Usually feed more alfalfa, carrots, corn, millet, eggs, etc. rich in protein, vitamins and minerals, among which millet should account for no more than 50% of the concentrate amount and should not be fed too much, otherwise it easily makes sheep obese. During the mating period, for rams with heavy mating tasks, appropriately increase the supply of protein, vitamin A, vitamin E and minerals, and add one egg with shell per day to ensure their strong libido and mating ability. In addition, breeding rams also need a relatively large activity area, with daily exercise time of no less than 6 hours.
The focus of feeding and management of ewes is to master the supplementary feeding period well, that is, from late gestation to early lactation, about 4 months. In late gestation the fetus grows rapidly, and 90% of the birth weight is gained during this period. If nutrition is insufficient, the lamb's birth weight is small, its thermoregulatory function is incomplete, its resistance is weak, and it is extremely easy to die; the ewe is also prone to postpartum agalactia. In early lactation, different supplementary feeding standards should be given according to the ewe's condition and the number of lambs she is nursing. Within 1 day to 3 days after lambing, reduce the amount of concentrate fed and feed only high-quality dry hay to prevent indigestion or mastitis. After that, strengthen supplementary feeding so that the ewe produces enough milk and ensures strong ewes and plump lambs. Within 1 day to 3 days after birth, lambs should promptly receive colostrum; from 15 days to 20 days of age, begin training them to eat grass and feed, and do supplementary feeding promptly; wean at 4 months of age to speed up the ewe's recovery of body condition. In addition, 1 month to 1.5 months before mating, ewes in poor condition should receive short-term flushing to restore body condition and promote estrus. During the mating season, feed more green and succulent feed. The sheep shed should be dry, clean and warm, and the bedding should be changed frequently. In winter, strictly prevent the sheep flock from drinking water with ice particles.
????Breeding multi-fetus varieties and selecting high-quality groups within varieties
Selection within the breed - selecting and retaining multi-lamb breeding rams and ewes: the prolificacy of rams and ewes has obvious heritability, so in the process of breeding and raising the sheep flock, attention should be paid to selecting and retaining excellent individual rams from twin and multiple births as breeding rams, and selecting and retaining excellent twin and multiple-birth ewes or their female offspring as foundation ewes, which can significantly increase the lambing rate.
Breeding multi-fetus varieties means introducing bloodlines of multi-fetus varieties for crossbreeding, using heterosis to make the sheep flock with fast growth and high lambing rate grow rapidly. For example, crossbreeding Small-tailed Han sheep with Polled Dorset sheep significantly improves both the lambing rate and meat production performance of the first-generation hybrids.
?Timely mating
Spring, summer and autumn are the peak periods for estrus and reproduction in the sheep flock. Generally, estrus in sheep lasts from several hours to 3 days to 4 days. Therefore, during feeding and management, special attention should be paid to the estrus status of ewes to ensure timely mating. When a ewe is found to be restless, eating little, bleating continuously, actively approaching the ram and wagging her tail, with hind legs spread apart, vulva congested and swollen, and standing still when the rump is pressed by hand, she has reached the peak of estrus and can be mated. Ewes generally begin mating at around 9 months, and rams generally begin mating at around 1.5 years. The best mating method is mainly artificial insemination, supplemented by natural mating. Regardless of the mating method, repeated mating should be used (that is, mating again about 12 hours after the first mating). In natural mating, the ratio of rams to ewes in the flock is best at about 1:25.
?Timely culling and replacement
During the breeding process of sheep, special attention should be paid to increasing the proportion of ewes of suitable age in the flock (generally requiring ewes of suitable age to account for more than 60% of the flock), promptly culling old sheep over 7 years of age, and ewes that are infertile, have habitual abortion, poor maternal behavior, poor lactation, give birth to single lambs or stillborn lambs, or have defects in the reproductive organs and udder, and add young ewes with tall stature and good growth and development to the flock every year.