Technical measures for breeding and management of sheep

Spring, summer and autumn are the peak periods of sheep oestrus and reproduction. The oestrus of sheep lasts for several hours to 3 - 4 days. Therefore, in the process of feeding management, special attention should be paid to ewe estrus to ensure timely mating. It was found that the ewes were restless, fed less, chirped constantly, approached the ram actively and swung their tails, their hind limbs were spread apart, their vulva was congested and swollen, and their hands pressed their arms to stand still. At this time, they reached the peak of estrus and could be mated. Female sheep generally begin mating at about 9 months of age, and male sheep generally begin mating at about 1 and a half years of age. Artificial insemination is the main method of breeding, and natural mating is secondary. No matter which mating method is used, repeat mating (i.e., repeat mating about 12 hours after the first mating) is used. The best ratio of male to female in natural mating sheep is about 1:25.

In the breeding process of sheep, special attention should be paid to increasing the proportion of age-appropriate ewes in the flock (generally, the proportion of age-appropriate ewes in the flock is more than 60%), timely eliminating old sheep over 7 years old, infertile, habitual abortion, poor motherhood, poor lactation, single lambing, dead lambing, defective reproductive organs and breasts, and supplementing young ewes with tall physique and good growth and development into the flock every year.

Fertility is the ability to express the reproductive function of livestock and the ability to bear offspring. In sheep production, improving the fecundity of ewes is the key link to increase economic benefits. There are many factors restricting ewe fecundity, such as breed, age and environment. Up to now, many sheep farmers in rural areas of our province are still grazing and breeding freely. Long-term hybridization and inbreeding greatly affect the fecundity of sheep. In addition, improper feeding management and hygiene factors are also the reasons for the low fecundity of sheep farmers in rural areas. Facing the increasingly prosperous sheep market, the author thinks that in order to improve the fecundity of sheep and obtain more economic benefits, the following technical links should be paid attention to in production.

1. The fecundity of ewes of different breeds of sheep with high quality is different to a great extent. For example, the double lambing rate of Hu sheep, small tail Han sheep and Landrace sheep in Finland is much higher than that of other breeds, and the lambing rate can reach 200%~300%. It is also reported that the green goats in Jining area of Shandong Province have strong procreation, sometimes producing 3~5 fetuses per fetus. The fecundity of ewes is heritable, and the offspring of ewes that generally produce two lambs will also have this high fecundity. According to the research, the average lambs produced by the ewes with single lambs at the beginning were 1.33, 1.31 and 1.04 in the following three births, while the lambs produced by the ewes with double lambs at the beginning were 1.73, 1.71 and 1.88 respectively. Therefore, the introduction of high-yielding varieties for crossbreeding and improvement, and the selection of their own existing sheep, long-term adherence will improve the fertility of the entire flock. High-quality breeding rams can be selected by determining the reproductive performance of their mothers and offspring, and must come from the offspring of high-yielding ewes.

2. Improving the feeding level of breeding rams and ewes Nutritional conditions have great influence on the reproductive ability of rams and ewes. Adequate and complete nutrition can improve the sexual desire of the breeding ram, improve the quality of semen, and promote the increase of estrus and ovulation number of ewes. The following is an example of raising small tail Han sheep.

Ram breeding Ram breeding in the breeding to maintain its robust, medium above the situation. The forage fed at ordinary times should be nutritious and comprehensive. It is recommended to use high-quality forage such as alfalfa. During the non-mating season, the ram was fed 0.5 kg concentrate, 2 kg hay, 0.5 kg green fodder, 5~10g salt and 5~10g bone meal daily. From 40 days before mating, 0.7~ 0.8 kg concentrate was supplemented daily, and then increased gradually. During breeding period, feed concentrate 1.2 kg, hay 2.5 kg, carrot 0.5~1kg, egg 2~3, salt 5~10g, bone meal 5~10g daily, grazing properly. Keep exercising for about 2 hours a day and massage testicles every day. During the non-breeding period, the breeding rams were fed with 2.5 kg of high quality hay, 1.0~ 1.5 kg of juicy feed and 0.8 kg of mixed concentrate daily. During the breeding period, they were fed with 1.0~ 1.5 kg of green feed, 1.0~ 2.0 kg of mixed concentrate, 2~3 eggs, 5~10g of salt and 5~10g of bone meal daily.

Breeding of ewes Under grazing conditions, ewes in empty gestation period do not need supplementary feeding when they can eat enough every day. In winter, some hay can be supplemented appropriately. For ewes with poor body condition, short-term preferential feeding can be implemented about 40 before mating to promote their estrus and ovulation. Pay attention to keeping the ewes in 7 - 8 minutes of emo. During the first 3 months of pregnancy, the fetus develops slowly and does not require supplementary feeding except during the period of withered. In the second 2 months of gestation, the fetus grew rapidly, and the energy metabolism and substance metabolism of ewes increased by 30%~40% compared with those in the empty gestation period. At this time, each ewe can feed 0.45 kg mixed concentrate, 1~ 1.5 kg green hay, 0.5 kg green feed and 5~10g bone meal daily. During pregnancy, attention should be paid to protecting the fetus and minimizing stress to the ewes. During lactation, ewes with single lambs should be given 0.3~0.5kg concentrate, 0.5kg green hay and 1.5kg succulent feed per day. The ewes with twin lambs were supplemented with 0.4~ 0.6 kg mixed feed, 1kg green hay and 1.5 kg juicy feed daily. In the late lactation period, since lambs are no longer completely dependent on breast milk as the main source of nutrition, it is necessary to appropriately reduce the amount of feeding to ewes.

3. Keeping the appropriate proportion of fertile ewes in flock whether the flock structure is reasonable or not has a great influence on the fecundity of flock. The double lambing rate of ewes increased with age, reached the highest level after 1~3 years, and began to decrease after 6~7 births. The main reasons for fertility decline of aged ewes are sexual function decline, poor egg quality, decreased conception rate due to weakened uterine function and increased embryo death. Therefore, increasing the proportion of age-appropriate ewes (2~5 years old) in the flock is an important measure to improve sheep fertility. In sheep breeding farms, the proportion of fertile ewes can be increased to 60%~70%, and it should be controlled at more than 40%~50% in most agricultural areas.

4 Scientific breeding

The selection of breeding season breeding time is mainly based on what time lambing is most conducive to the survival of lambs and maternal and child health to decide. Summer weather is hot, ram sexual desire weakens, semen quality drops; winter ewes body condition is bad, difficult to estrus or low rate of estrus conception. The selection of most areas in our province is carried out only once a year, autumn breeding, that is, breeding in October ~ November every year, lambing in March ~ April of the next year. The advantages of such breeding are: when the ewe is pregnant, due to better nutritional conditions, the birth weight of the lamb is relatively large, and the lamb can eat grass after weaning, so the growth and development is faster, and the overwintering ability of the first year is relatively strong. In addition to autumn breeding, breeding can also be carried out in spring, that is, April to May of each year. Breeding at this time requires sufficient forage and feed to be stored in winter and a well-insulated sheep house to be prepared.

There are two methods of breeding sheep: natural mating and artificial insemination. Natural mating is the most primitive way to raise sheep, that is, male and female mixed herding in breeding season, which saves labor and does not need equipment. However, this method has a lot of bad effects on the fertility of the whole flock. Because of inbreeding, it is difficult to select and match sheep in the future, and it will produce many abnormal fetuses, which directly reduces the fertility of the flock. Artificial insemination can effectively improve the above shortcomings, it can expand the utilization rate of excellent rams, improve the conception rate of ewes, and improve the fertility of sheep. If artificial insemination is not carried out, artificial auxiliary breeding can be adopted, that is, male and female sheep are divided into groups, female sheep are tested every day in breeding season, and then female sheep in estrus are mated with designated rams, which is beneficial to sheep selection and selection.

Strengthen the management level before and after childbirth. All kinds of instruments should be disinfected before childbirth. The tail root, vulva, anus and udder of ewes should be disinfected with 1% Lysol or 1‰ potassium permanganate solution. After the lambs are born, the umbilical cord is shortened at a distance of 5~8 cm from the umbilicus of the lambs and disinfected with iodine tincture. If there is a dead lamb, lift its hind legs in time, pat its back, or let it lie flat, and press its chest rhythmically with both hands to revive it. Have dystocia occurs, check its fetal position can be artificial midwifery, otherwise find veterinarian caesarean section. After the fetus is born, let it eat colostrum in time, eat early, train to eat grass, discharge meconium and enhance gastrointestinal motility. Newborn lambs have poor resistance, so nursing care should be strengthened. If the ewe milk is insufficient, artificial lactation or foster care should be taken in time.