Reproduction is a key link in sheep production. Whether it is the development of the number of herds or the improvement of the quality of herds, it must be achieved through the breeding process and good economic benefits can be obtained. Therefore, various methods and approaches should be adopted to increase the fecundity of dairy goats. Emphasis on the breeding of multiple fetuses based on basic ewes
The multiple fetal properties of the ewes directly affect the fecundity of the entire flock. Therefore, we should first select the ewes with good reproductive performance and set up the basic group. In the future generations, we will not introduce other breeding sheep in the breeding process, and practice breeding at the same time. At the same time, we should avoid close relatives of all our compatriots (brothers and sisters). The third generation should be avoided. The population inbreeding coefficient is controlled within 12.5%.
Continuous introduction of multiple fetal genes
Through the continuous introduction of multi-hybrid breeding and improvement, population fertility can be effectively and rapidly increased. Milk goats are only second to pigs in fertility. For example, Xi Nong dairy goats are generally sexually mature from 5 months to 6 months of age, and when the feed conditions are good, 7 months to 8 months of age can be used for breeding. The number of follicles in mature estrus of dairy goats is 2 to 5, which is higher than that of sheep and cattle. The average lambing rate is about 200%. Most of them are twin lambs, 3 lambs are also more common, and even one baby has 6 lambs to 7 lambs. For example, Nubian milk goats have two babies a year, 2 lambs to 3 lambs per fetus, and their reproductive power ranks first among dairy goat breeds. The multi-fetal nature of goat breeds is important in breeding. It determines the value of the sheep and the economic benefits of a breed.
There are more than 60 types of dairy goats in the world, of which the famous Swiss-based Shannen dairy goats, the Tütkenburg dairy goats, the French Alpen dairy goats, the German dairy goats, the English British goat milk goats and the North African breeds. Nubia dairy goats and more than 10 varieties. China has introduced Shauneng Dairy Goat, Tugubao Dairy Goat, Nubian Dairy Goat and Gaisen Dairy Goat, and has nurtured Xinong Shaneng Dairy Goat, Guanzhong Dairy Goat, Laoshan Dairy Goat, Tangshan Dairy Goat, and Yanbian Dairy Goat. Other varieties.
Xi Nong Sha Neng Dairy Goat is a good dairy goat breed that has been introduced into Canada by the Northwest Agricultural University. It has been introduced into many regions of the country and has made great contributions to the improvement of dairy goat breeds and the cultivation of new varieties.
Xi Nong Sha Neng Dairy goats are sexually mature and have strong reproductive ability. Male and female ewes are generally sexually matured from 4 months to 6 months, and are mated from 8 months to 10 months of age. The estrus season is from August to December each year, and from September to November is the estrus peak season. Generally produce two or three lambs, the lambing rate is above 200%. The lactation period is 10 months, with an annual output of about 800 kilograms of milk, and the highest daily milk yield is 10.05 kilograms. The useful life is 7 to 8 tires.
Choosing male lambs for breeding purposes
The milking rate of dairy goats has a more stable heredity. Research suggests that there are also many descendants of multiple births. The ewes with the largest number of lambs in the first birth also produce more lambs. According to statistics from the Northwestern Agricultural University on the Shauneng Flock, the first birth produces 1 lamb and the 5th breed totals 9.3 lambs. The first birth produces 2 lambs and the 5th breed totals 10.62 lambs. The first birth produces 3 lambs. The total number of lambs born from the 5th child is 13.18. There was a significant positive correlation between the number of first births and the number of final births. Therefore, the selection of the lambs' lamb performance in the first litter ewes can increase the lambing rate of the lambs. The trial also showed that selecting rams with higher lambing rates to mate with multiple ewes is genetically more effective than selecting only multiple lamb ewes.
Maximize the proportion of female ewes
Timely elimination of infertile sheep and abortion ewes. If the proportion of ewe (2 to 5 years old) is enough to reach 65% to 70% in the entire flock, the herd fertility can be greatly improved. Ewes generally reach their best reproductive status by the age of 5, and 7-year-old sheep should be gradually reduced to form a "pyramid" structure, so that the sheep are always in a dynamic, reserve vitality state.
Improve the breeding and management level of breeding sheep
Full price nutrition and good management can improve the libido, ejaculation and semen quality of the ram, promote the growth and sexual maturity of the ewes, and allow the ewes to have early estrus and multiple ovulation. In production practice, in order to make empty ewes more ovulated and more fetuses, full feeding can be given within one week before and after estrus breeding, and the amount of daily feed fed can be increased by 10%. This is called support breeding of estrus breeding. During mating season, grazing and feeding of male and female ewes should be strengthened to meet the nutritional needs of the sheep. The breeding rams should be supplemented with protein feeds, such as eggs, fish meal, goat milk, and pig blood, and supplemented with ram nutrition (mainly protein) consumption to improve semen quality. In addition, while awakening the aphrodisiac, we must also be careful not to make the breeder sheep obese. Rams should be used rationally, excessive use will reduce sexual desire, semen quality is poor, and conception rate is low. Ewes must discover estrus in time, match breeding at the right time, and increase fertility rates.
Two-year-old litter-bearing model
Two-year, three-child births are performed once every eight months under good husbandry and management conditions, ie from August to September each year, and from January to February in the following year; from March to April, from August to September. Lambing; breeding from November to December, lambing from April to May of the following year. Lambs are generally weaned from 2 months to 3 months of age.
Inducing multiple births
At present, China has developed a multiple birth-producing drug called HC-A double lamb, 40 milligrams before intramuscular injection, 2 ml intramuscular injection of double lamb, 28 days to 30 days after the injection, the amount of 2 ml, 10 days later The estrus breeding can increase the lambing rate by 27.97%.
In addition, the use of exogenous hormones (such as maternal serum) combined with feeding aphrodisiac can increase the ovulation rate and increase the proportion of double lambs. The use of exogenous hormones is: the first day of injection of 800 international units of pregnant horse serum, the next day, 1 mg of prostaglandin injection, 95% of the ewe in 3 days. This method must be combined with improving feeding and management conditions in order to receive good results.
Adopt new breeding technology
The promotion of artificial insemination and frozen semen technology has greatly improved the utilization rate of rams. The application of techniques such as estrus, superovulation, embryo transfer, embryo segmentation, and nuclear transfer at the same time has enabled the ewes' reproductive function to be fully utilized, thereby enhancing the breeding efficiency of the sheep. Strengthening the diagnosis of early pregnancy and prevention of infertility can reduce empty space and increase reproduction rate. The use of inhibin and ram effects can promote estrus and ovulation, which can help increase reproduction rates.
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