Feeding and management techniques of fattening sheep ⅰ. Production characteristics of sheep
In order to make full use of pasture and straw, sheep breeding in China mainly adopts grazing in pastoral areas and free-range farming in agricultural areas. In production, seasonal breeding and delivery are generally carried out according to the natural estrus of sheep. The delivery time is generally between11-65438+February for winter lambs and March-April for spring lambs. Generally speaking, the delivery and lactation of ewes end within 40-50 days, so mating should also be completed in estrus after lactation.
Second, the grazing mode of sheep
1. Fixed grazing. Sheep are free to graze in specific areas all year round, which is a primitive grazing method. This method is not conducive to the rational utilization and protection of grassland, with low livestock carrying capacity, less livestock products per unit grassland area and low value created by each labor force. There is a balance between the number of livestock and grassland productivity, and more livestock will inevitably die. This is a grazing method that modern sheep industry should abandon.
2. Fence grazing. Surround the pasture according to the terrain, and arrange a certain number of sheep to graze in the fence according to the amount of nutrients provided by the pasture and the nutritional needs of sheep. This method can reasonably utilize and protect grassland, and also plays an important role in determining the right to use grassland.
3. Complete imprisonment. Full captivity is a kind of breeding method with the development of large-scale sheep industry in recent years. This method requires high pens, infrastructure and funds, and makes full use of coarse feed such as light industry leftovers or by-products, silage straws, supplemented by concentrate supplements with higher nutritional level, thus making the production level higher. Through high-level feeding management, the production potential of sheep can be fully tapped and the maximum production and economic benefits can be obtained.
Third, the fattening method of sheep
1. grazing and fattening. It is suitable for areas with good grazing conditions, which not only makes full use of local forage resources, reduces production costs, improves economic benefits, but also speeds up the turnover of sheep and reduces the pressure on grasslands in winter and spring. Grazing and fattening should seize the best opportunity of lush grass and high nutritional value in summer and autumn to fully extend the effective grazing time every day. In areas with conditions in the north, we should make full use of grasslands, go out early and return late, and do not rest at noon; In the south, we should take active measures to graze early and late. When the climate is hot, we should pay attention to driving the sheep back to the sheepfold or rushing to the shade to rest. In agricultural areas, the harvested cultivated land can be fully utilized for grazing in autumn. The fattening period of grazing is generally August-June, 65438+ 10. At this time, the forage grass begins to bear seeds, which is nutritious and easy to digest, and can effectively improve the fattening conditions and reach the slaughter standard.
2. House feeding fattening. In order to adjust the market demand for mutton and make full use of various industrial and agricultural by-products to fatten mutton sheep, the modern specialized and intensive mutton sheep breeding industry adopts standardized fattening methods. In this way, agricultural straws and agricultural and sideline products should be fully and reasonably utilized, and the fattening process should be timed, quantified, fixed in quality and temperature. Pay attention to the unified and reasonable collocation of forage and feed, ensure the palatability of feed, meet the nutritional needs during the cultivation of strong chemical fertilizers, and supply sufficient clean drinking water. The fattening period is generally 60-90 days, and the weight can be increased by 10- 15kg under better feed conditions, which can effectively improve the ketone weight and mutton quality in a short time.
3. Mixed fattening. It can not only shorten the production date, increase the number of slaughter and meat production, but also make full use of forage resources, reduce production costs and improve production efficiency. There are two kinds of mixed fattening:
1, in late autumn and early winter, after forage withers, at the same time of grazing and fattening, concentrate is used for supplementary feeding, fattening time is extended, intensive fattening is carried out, so that it can reach the slaughter standard, and the ketone weight and mutton quality are improved.
2. The quality of grassland is poor, and simple grazing can not meet the nutritional requirements of rapid fattening. Therefore, at the same time of grazing, fattening sheep are supplemented with certain mixed concentrate and high-quality hay, so that the diet nutrition can reach the feeding standard of fattening sheep.
Key points of fattening sheep feeding management 1. Sheep yield-increasing technology
If the breeding plan is carefully arranged and the breeding time is reasonably determined, at 1, the sheep can give birth to 2 or 3 fetuses every 2 years.
The average pregnancy days of sheep are 148.33 days, and most ewes can be in estrus for mating more than 40 days after delivery. The estrus of small-tailed Han sheep is concentrated in spring and autumn, so the second child of 1 can be bred in March-April, lambing in August-September, or mating in 9- 10, and the second child can be born in February-March. Lambs born in February-March are at the peak of grass after weaning, which is a good season to cultivate reserve sheep; Fattening lambs born in August-September is a good opportunity to supply mutton to the market in winter. Sheep with triplets in two years can give birth in August-September, 65438+ 10165438+10, and then give birth in March-April. If supplemented by synchronous estrus technology, the effect is better.
Second, synchronous estrus
Estrus synchronization is a periodic treatment of ewe estrus.
1. Common drugs for estrus synchronization. Generally, there are two kinds: one is a preparation for inhibiting estrus, which belongs to progestational substances, such as progesterone, medroxyprogesterone acetate, norethindrone chloride, fluoprogesterone, norethindrone 18 and so on. They maintain a certain level in the blood and can inhibit the growth and development of follicles. The other is gonadotropins, such as follicle stimulating hormone, luteinizing hormone, PMSG and HCC, and gonadotropin releasing hormone (GnRH) which can promote the release of endogenous gonadotropins. The purpose of using these hormones is to promote the growth, maturation and ovulation of follicles, make the synchronization of estrus and ovulation reach a higher level, and improve the pregnancy rate.
2. The treatment method of estrus synchronization. The most commonly used method is vaginal embolization: take a piece of sterilized foam plastic, whose diameter and thickness depend on the size of the sheep, generally 2 cm -3 cm. If it is too small, it will easily slip off, and if it is too big, it will easily cause the ewe to complain and be squeezed out. A sterilized thin thread is hung on the foam plastic, and the other end of the thread is led out from the vaginal opening, which is convenient for pulling out at the end of treatment. Soak the foamed plastic in the progestogen preparation solution and insert it into the external cervix with sterilized long-handled pliers. 14 days to16 days later, the ewes were taken out and injected with PMSG400 -700 international units intramuscularly. After 2 -3 days, most of the treated ewes appear estrus, and insemination can be carried out 1 time on the day of estrus and the next day.
The types and reference doses of drugs are generally: megestrol acetate 40 mg -60 mg, megestrol acetate 40 mg -50 mg, norethindrone 18 30 mg -40 mg, chloroprogesterone 20 mg -30 mg, chloroprogesterone 30 mg -60 mg and progesterone 150 mg -300 mg.
Third, pregnancy and its care
After mating 18 -20 days, the ewe no longer estrus, which can be preliminarily judged as pregnancy. When the ewe is pregnant for 3 months, the fetus has formed, and there is a lump in front of her breast by touching her abdomen. The fetus grows rapidly at 4-5 months, and the material metabolism and total energy metabolism in ewes increase sharply. At this stage, the ewe's abdomen is enlarged, her nest collapses, her breasts are enlarged, her actions are careful and slow, and her temperament is docile. During this period, it is most necessary to strengthen feeding management. If the nutrition is insufficient, especially protein, calcium and phosphorus deficiency, it is easy to cause miscarriage or premature birth of ewes.
Measures to protect the fetus are:
Foraging in groups. Pregnant ewes should not be mixed with other sheep, but should be fed in groups;
Ensure nutrition. Ewes should be fed better feed during pregnancy, especially in the middle and late pregnancy, and the fetus develops rapidly. It is necessary to strengthen the nutrition of ewes, supply rich and complete nutrients, such as leguminous forage, juicy feed and mineral feed (bone meal), and appropriately increase the supply of concentrate;
Lambs are weaned early. If the ewe 1 gives birth to two fetuses, the lamb will be weaned at the age of 3 months, so that the ewe can recover as soon as possible without affecting the growth and development of the lamb;
Prevent diseases. Pregnant ewes are prone to miscarriage when they are sick. Therefore, ewes should pay attention to the sanitation of pens during the whole pregnancy, do a good job in cold prevention or heatstroke prevention, avoid eating moldy and toxic feed and prevent various diseases.