Rapid breeding method of new Tibetan sheep variety

Abstract

The invention discloses a rapid cultivation method of a new Tibetan sheep variety, and belongs to the field of livestock breeding and breeding in animal husbandry. According to the method, the genes of the Australian white sheep and the Hu sheep are introduced on the basis of the Tibetan sheep variety for the first time, the hereditary characters of the Tibetan sheep account for 25%, the Australian white sheep account for 25%, and the Hu sheep account for 50%, the stress resistance of the Tibetan sheep is kept from the perspective of the hereditary characters, 50% of the hereditary characters of oestrus all year round and polyembryony are introduced, and meanwhile 25% of the hereditary characters which are fast in growth, suitable for grazing and high in stress resistance are introduced. Under the same grazing, supplementary feeding, breeding and epidemic disease prevention and control modes as Euler sheep, the new Tibetan sheep variety bred by the method has the genetic and production characteristics of high adaptability, high breeding and high yield, high growth speed and the like.

Description

Technical Field

[0001] The invention relates to the field of animal husbandry and livestock breeding, and in particular to a method for rapidly breeding a genetically improved new breed of Tibetan sheep. Background Art

[0002] With the rise of the mutton industry, sheep farming has changed from a family sideline to a major industry in the rural economy, becoming an important source of income for farmers and a new way to increase income, and realizing the transformation from a means of livelihood to industrial promotion. Northwest my country, such as Qinghai, Xinjiang, Tibet and other places, mainly raise sheep. Local breeds in various places have strong resistance to adversity, but low breeding efficiency. In the past, sheep farmers only focused on breeding within their own breeds, and did not pay attention to the introduction and use of excellent breeds. With the rapid development of the sheep industry, there have been great changes in the understanding and use of breeding breeds. First, gradually strengthen the protection measures for local excellent breeds with strong adaptability, strong disease resistance and good reproductive performance, and continue to select and breed to ensure that germplasm resources are not lost. Second, use these local mutton sheep breeds as maternal parents, introduce excellent breeding rams with strong adaptability, good meat production performance, fast growth rate and high feed remuneration from home and abroad to hybridize and improve local breeds, use hybrid advantages to produce commercial sheep, and use modern biotechnology to accelerate the breeding and production of mutton sheep, so as to achieve the purpose of transformation and upgrading of the mutton industry, improve quality and efficiency, and ensure supply.

[0003] Tibetan sheep, also known as Tibetan sheep, is one of the three original sheep breeds in my country. It is mainly distributed in the Qinghai-Tibet Plateau, and Qinghai Province is its main production area. As one of the important livestock in the plateau area, Tibetan sheep has the characteristics of adapting to the plateau environment and delicious meat. However, the existing Tibetan sheep breeds have certain limitations in production performance, adaptability, genetic stability, etc., such as seasonal estrus and low reproduction rate (one litter per year, very few ewes have three litters in two years and more than 98% are single lambs), slow growth rate (daily weight gain less than 100g), and medium slaughter rate (42%-49%), which limit its breeding efficiency and market competitiveness.

[0004] In recent years, with the rapid development of animal husbandry and the diversification of consumer demand, the market demand for new Tibetan sheep breeds with high reproduction, high yield, fast growth rate and high-quality meat has increased. In order to improve the production performance of Tibetan sheep, the multi-hybridization breeding method can effectively improve the Tibetan sheep breed and improve its production performance and adaptability. However, these methods face technical challenges in actual operation, such as maintaining genetic diversity and stable inheritance of excellent traits.

[0005] Therefore, breeding a new breed of Tibetan sheep with the characteristics of year-round estrus, high lambing rate, pure white coat, no horns, suitable for grazing, strong resistance to adversity, fat lambs on the plateau, and tender meat is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0006] In view of this, the present invention provides a method for rapidly breeding a new breed of Tibetan sheep. Based on conventional breeding techniques such as production performance measurement, assisted by molecular breeding techniques, using a ternary hybrid combination, combined with a feeding mode of grazing and supplementary feeding, strict selection criteria, combined with modern efficient breeding techniques such as live egg collection, in vitro embryo production, embryo transplantation and surrogacy, the aim is to rapidly breed a new breed of Tibetan sheep with the characteristics of year-round estrus, high lambing rate, pure white coat, no horns, suitable for grazing, strong resistance to adversity, fat lambs on the plateau, and tender meat, and rapidly expand the purebred population.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] A method for rapidly breeding a new Tibetan sheep breed comprises the following steps:

[0009] (1) Using Australian White Sheep, Hu Sheep and Oula Sheep as parents;

[0010] (2) hybridizing with Australian white sheep as the male parent and Hu sheep as the female parent to produce the Australian-Hu hybrid F1 generation; then hybridizing with Oula sheep as the male parent and Hu sheep as the female parent to produce the Tibetan-Hu hybrid F1 generation;

[0011] (3) The F1 generation of Australian-Lake hybrid sheep and the F1 generation of Tibetan-Lake hybrid sheep were raised for grazing after weaning;

[0012] (4) Using the F1 generation of Australia-Lake hybrid as the male parent and the F1 generation of Tibet-Lake hybrid as the female parent for cross-crossing, the cross-crossing obtains the F1 generation of Australia-Tibet-Lake cross-cross sheep, and maintains grazing and breeding;

[0013] (5) Using the F1 generation of the Tibetan-Hu hybrid as the male parent and the F1 generation of the Australian-Hu hybrid as the female parent for cross-crossing, the Tibetan-Australian-Hu hybrid F1 generation sheep are obtained by cross-crossing, and the sheep are kept for grazing;

[0014] (6) The F1 generation sheep obtained by cross-crossing between Ao-Zang-Hu and Zang-Ao-Hu were collected for birth weight, number of siblings, multiple birth gene carrier status, coat color and disease history; the feeding management and disease prevention and control mode was the same as that of Tibetan sheep, with ewes being grazed and lambs being supplemented with food, and the F1 generation sheep of Ao-Zang-Hu were grazed after weaning;

[0015] (7) Use the F1 generation of crossbreeding between Ao-Zang-Hu and Zang-Ao-Hu as the male and female parents for further crossbreeding and maintain the grazing mode;

[0016] (8) The cross-cross F2 sheep obtained by cross-crossing of Ao-Zang-Hu Lake were collected for lactation performance of Ao-Zang-Hu Lake cross-cross F1 ewes and birth weight, number of siblings, multiple birth gene carrier status, coat color and disease history of cross-cross F2 sheep; the feeding management and disease prevention and control mode were the same as those of Tibetan sheep, with ewes grazing and lambs supplementary feeding, and the Ao-Zang-Hu Lake cross-cross F2 sheep were raised for grazing after weaning;

[0017] (9) Repeating steps (7) and (8) until the Ao-Tibet Lake crossbreed F4 generation sheep is obtained, the excellent traits are finally fixed, and a purebred group is established; using modern and efficient breeding technologies such as live egg collection from Ao-Tibet Lake crossbreed F4 generation ewes, freezing of breeding sheep semen, in vitro embryo production, embryo transplantation and surrogacy, the herd is rapidly expanded to complete the rapid breeding of a new Tibetan sheep breed.

[0018] In the present invention, the selected Oula sheep is a Tibetan sheep with a large breeding volume (about 1 million) and the best meat production performance in Qinghai and other places. The Oula ewes have good maternal nature and strong lambing ability. Generally, ewes start to estrus at the age of 1.5 years and have a breeding period of 5 to 6 years. Lambs are born once a year, with one lamb per litter. The average estrus cycle of ewes is 17.54 days and the gestation period is 151.31 days. The local custom is to produce winter lambs, generally breeding in July to September, and lambing from December to February of the following year. The reproductive survival rate of 1.5-year-old ewes is 48%, and the reproductive survival rate of adult ewes is 68%. The average weight of 6-month-old rams is 35.14 kg, and that of ewes is 31.44 kg. The average weight of 1.5-year-old rams is 48.09 kg, and that of ewes is 52.76 kg; the average weight of adult rams is 66.82 kg, and that of adult ewes is 52.76 kg. The carcass weight of a 1.5-year-old wether is 18.05 kg, the visceral fat is 0.74 kg, and the slaughter rate is 47.81%; the carcass weight of an adult ewe is 25.83 kg, the visceral fat is 2.15 kg, and the slaughter rate is 48.1%. The protein content of Oula mutton is between 19.0 and 22.0 g / 100 g, the fat content is between 3.0 and 6.0 g / 100 g, or about 3.15%, and it is rich in various minerals, such as calcium, iron, zinc, and phosphorus. Specifically, the calcium content is between 3.0 and 3.4 mg / 100 g or 8.6 mg / 100 g, the iron content is between 1.5 and 1.7 mg / 100 g or 3.02 mg / 100 g, the zinc content is between 1.5 and 1.9 mg / 100 g or 3.9 mg / 100 g, and the phosphorus content is between 180 and 250 mg / 100 g. Oula mutton contains 16 kinds of amino acids, with a total amount of 16.0g to 17.5g / 100g. It has a firm texture, rich taste when chewed, not dry or greasy, with a strong mutton aroma, and little mutton smell. Oula sheep adapt to the high-altitude and oxygen-deficient plateau environment, and have strong adaptability to the natural conditions of low pressure, severe cold, and humidity in the alpine grassland. However, the Tibetan sheep in the plateau pastoral areas represented by Oula sheep have shortcomings such as seasonal estrus, low lambing rate, low lamb survival rate, coat color (low fur value), slow growth rate, and low slaughter rate.

[0019] As one of the world's famous multi-birth sheep breeds, Huyang is a unique sheep breed in China. Huyang likes dryness and hates humid environments. It has excellent traits such as tolerance to roughage, strong environmental adaptability, estrus in all seasons, multiple births and high production, good lactation performance, and fast growth and development. Purebred Huyang male and female sheep are hornless and have white fur all over their bodies. The weight of adult rams is 53.0-58.0 kg, and the weight of adult ewes is 42.0-50.0 kg. The slaughter rate of mutton sheep is 47%-56%, and the daily milk production of multiparous ewes generally reaches about 2.1 kg. The average lambing rate is 212%, and the lambing rate of Huyang multiparous ewes can generally reach 220%-240%. The main advantages of Huyang are year-round estrus, strong multiparous lactation ability, high litter size and high lamb survival rate. The meat is delicious and delicate with little mutton smell. Hu sheep grow and develop rapidly in the early stage and reach sexual maturity early. The live weight can reach 30.0 kg at 6 months of age. Young ewes can be bred when they are 7 or 8 months of age. Hu sheep have good adaptability to house feeding, are resistant to roughage, moisture and heat, can adapt to the southern environment and survive in the northern environment, but they also have disadvantages such as weak stress resistance, low slaughter rate and low feed return.

[0020] Australian white sheep have white fur, large size, fast growth rate, strong adaptability, excellent meat quality, high slaughter rate, early maturity and mild temperament. Under grazing conditions, the carcass weight of Australian white sheep lambs aged 5 to 6 months can reach 23 kg; under shed conditions, the carcass weight of 6-month-old lambs can reach 26 kg. Australian white sheep are large in size, with the characteristics of fast growth and early maturity. Ewes are in estrus all year round, sexual maturity is 5 to 8 months old, the estrus cycle is 14 to 20 days, and the lambing rate can reach 130% to 180%. The first breeding age of sheep is 9 to 10 months old, and rams can be bred all year round, with the first breeding age of 10 to 14 months old. Australian white sheep have better cold resistance, larger size, faster growth rate, better meat production performance, better tolerance to roughage, high feed conversion rate and strong anti-parasitic ability. Australian white sheep have even fat coverage and a high proportion of high-quality meat. The meat of Australian White sheep is obviously marbled, juicy, and suitable for cooking mid-to-high-end mutton products at home and abroad. Australian White sheep is a meat sheep breed with good limb structure, strong walking ability, and high production performance, especially in terms of stress resistance, growth rate, reproductive performance, meat production performance and meat quality. Crossbreeding Australian White rams with local breeds in my country can effectively improve the growth performance and meat performance of the offspring.

[0021] Studies have shown that when Dorset sheep and Qinghai Oula sheep were hybridized, the live weight and carcass weight of the hybrid offspring F1 before slaughter were significantly higher than those of purebred Oula sheep; some scholars even used Suffolk and Tibetan sheep for hybridization, and the daily weight gain of F1 rams was 163.56g, 131.39g higher than that of purebred Tibetan sheep, and the economic benefits were significantly improved. Some scholars also used Australian white sheep as the paternal parent and Qinghai plateau Tibetan sheep as the maternal parent for hybridization, and their offspring had obvious paternal characteristics: the survival rate, tolerance to roughage, disease resistance and adaptability to the local environment were no different from those of local Tibetan sheep, and the body size, average daily weight gain, feed-to-weight ratio, etc. were better than those of local Tibetan sheep. Tibetan sheep have a low reproduction rate, slow growth rate, and low meat production, which seriously affects production efficiency and cannot meet the high-efficiency and high-quality needs of modern animal husbandry.

[0022] The present invention, through three-way hybrid breeding, combines the stress resistance of Oula sheep, the high fertility and lactation of Hu sheep, and the high feed conversion rate and slaughter rate of Australian white sheep, to cultivate a new breed of multi-birth meat Tibetan sheep with year-round estrus, a lambing rate of over 140%, fast growth and excellent meat quality, thereby improving the breeding efficiency and market competitiveness of Tibetan sheep in the Qinghai-Tibet Plateau.

[0023] Furthermore, in step (1), the ancestral line selection conditions are:

[0024] Australian White Aries (♂): From 4 different families, genetically stable, all are descendants of twins, fast growth rate, wide nose, big hole, more muscular head, distinct male characteristics, no horns, all white fur, well-proportioned body, tall and deep body, long cylindrical shape, straight waist and back, deep and wide chest, barrel-shaped, thick and powerful limbs, compact structure, gentle temperament, strong sociability and walking ability, symmetrical testicles, and no history of disease.

[0025] Hu sheep (♀): from 4 different families, genetically stable, all are descendants of twins or more, medium physique, narrow head, raised nose bridge, drooping ears, no horns, slender neck, narrow body, straight back and waist, slightly drooping abdomen, flat and round tail, medium to small, tail tip upturned, thin and tall limbs; all white fur, strong physique, symmetrical udder structure. FecB gene detection is BB type (mutant);

[0026] Oula sheep (♂): from 4 different families, genetic stability, strong resistance, strong physique, high limbs and large body, wide and flat back, deep chest, well-developed hindquarters, cross section slightly higher than body height. Head slightly narrow and long, sharp triangle, convex nose, slightly protruding eye, large ears, thick and long horns, short and thin tail, flat cone shape, symmetrical udder structure.

[0027] Criteria for judging the results of FecB gene detection in ancestral line selection:

[0028] The criteria for determining the FecB gene in breeding sheep are mainly based on its genotype. The FecB gene is derived from the bone morphogenetic protein receptor 1B (BMPR1B). The mutation of A to G at position 746 of the gene exon is the FecB mutation. According to the mutation, the FecB gene in breeding sheep can be divided into three genotypes: BB type (mutant type), B+ type (heterozygous type) and ++ type (wild type).

[0029] BB type: A mutation from A to G occurs at the 746th base of the CDS region of the FecB gene, resulting in a mutation from glutamine to arginine at the 249th base of the FecB protein. Sheep of this genotype usually have a higher fertility.

[0030] B+ type: It is a heterozygous gene, that is, it carries a mutant FecB gene and a wild-type FecB gene. The reproductive capacity of this genotype of sheep is between BB type and ++ type.

[0031] ++ type: The 746th base of the CDS region of the FecB gene has not changed and remains A. The reproductive capacity of this genotype of breeding sheep is relatively low.

[0032] In practical applications, the FecB gene of breeding sheep is tested by the above detection method, and its reproductive performance is determined according to its genotype. Studies have found that breeding sheep carrying BB or B+ FecB genes have higher fertility, which is an important goal for breeding high-fertility breeding sheep.

[0033] Furthermore, in step (2), the following operations are performed on the hybrid F1 generation of Australian Hu sheep and the hybrid F1 generation of Tibetan Hu sheep: the birth weight, number of siblings, multiparity gene carrier status, coat color and disease history of the hybrid F1 sheep are collected; the feeding management and disease prevention and control mode are the same as those of Tibetan sheep, with ewes grazing and lambs supplementary feeding;

[0034] Furthermore, in step (3), the estrus frequency, disease history, coat color, and presence of horns of the F1 generation of the Australian-Lake hybrid and the Tibetan-Lake hybrid are monitored at 6-8 months of age.

[0035] Step (4) The selection criteria for the F1 generation of the Sino-Australian-Lake hybrid are: birth weight ≥ 2.9 kg, number of siblings ≥ 2, slender tail, FecB gene of BB or B+ type, pure white coat color, no horns, and no history of disease; ewes are 7 months old, sexually mature, with normal udder and nipple hair and symmetrical structure; rams are 11 months old, sexually mature; rams have sperm motility higher than 78%, and sperm deformity rate lower than 14%;

[0036] The selection criteria for the F1 generation of Tibetan Hu sheep hybrids are: birth weight ≥ 2.6kg, triangular tail, number of siblings ≥ 2, FecB gene type BB or B+, white coat, no horns, no history of disease; ewes are 7 months old, sexually mature, with normal udder and nipple hair and symmetrical structure; rams are 11 months old, sexually mature; rams have sperm motility higher than 78%, and sperm deformity rate lower than 14%;

[0037] Furthermore, the selection criteria for the F1 to F3 generations of rams from the cross-breeding of the Australian Tibetan Lake in step (7) and step (8) are: birth weight ≥ 2.6 kg, number of siblings ≥ 2, slender tail, FecB gene of BB type, pure white coat color, no horns, no history of disease, symmetrical testicles, rams 11 months old, sexually mature; rams sperm motility higher than 78%, sperm deformity rate lower than 14%;

[0038] The selection criteria for ewes are: birth weight ≧2.4kg, number of littermates ≧2, slender tail, FecB gene of BB type, pure white coat color, no horns, no history of disease, natural estrus symptoms monitored at 6 to 8 months of age, physical and sexual maturity at 7 months of age, normal udder and nipple hair, and symmetrical structure.

[0039] Furthermore, the selection criteria for the F4 generation rams of the cross between China, Australia, Tibet and Lake in step (9) are: solid physique, relatively strong limbs, straight back, well-proportioned overall structure, slender tail, pure white coat, no horns, reaching physical and sexual maturity at 11 months of age, strong grazing, sociability and stress resistance, and FecB gene of BB type;

[0040] The selection criteria for ewes are: moderately straight trunk, well-proportioned limbs, slender tail, pure white coat, no horns, some ewes have two "meat bells" on their necks, reach physical and sexual maturity at 7 months of age, have strong grazing, sociability and stress resistance, lambing rate of more than 140%, are in estrus all year round, and the FecB gene is BB type.

[0041] Furthermore, in step (9), the semen is preserved by collecting high-quality adult ram semen from different families, diluting it 10 to 12 times, and freezing it in liquid nitrogen for later use;

[0042] Oocyte preservation is as follows: superovulation is performed on high-quality adult ewes from different families, oocytes are collected, matured in vitro and cryopreserved in liquid nitrogen for later use;

[0043] The ear tissue preservation is as follows: the ear tissues of high-quality adult male and female sheep from different families are collected, separated, identified, purified, subcultured into fibroblasts, and frozen in liquid nitrogen for future use.

[0044] The rapid expansion and breeding operation of the core population is as follows: starting from 12 months of age, the core group of Ao Zang Hu cross F4 ewes are superovulated once a month, and minimally invasive live egg collection is performed using a live egg collection device and laparoscopy. Through in vitro maturation of oocytes, in vitro fertilization, in vitro development of embryos and transplantation surrogacy technology, 10 to 15 live egg collections are performed on each breeding ewe, shortening the breeding cycle by 8 to 12 months, and each ewe produces more than 35 purebred offspring.

[0045] The beneficial effects of the present invention are as follows: the present invention provides a breeding method for a new Tibetan sheep breed, and for the first time introduces Australian white sheep and Hu sheep genes on the basis of the Tibetan sheep breed, wherein the genetic traits of the Tibetan sheep account for 25%, the Australian white sheep account for 25%, and the Hu sheep account for 50%. From the perspective of genetic traits, the stress resistance of the Tibetan sheep is maintained, 50% of the genetic traits of year-round estrus and multiple births are introduced, and at the same time 25% of the genetic traits of fast growth and suitability for grazing and strong stress resistance are introduced.

[0046] Under the same grazing, supplementary feeding, breeding and disease prevention and control model as the Oula sheep, the new Tibetan sheep breed has the following genetic and production characteristics: strong adaptability, fast growth rate, slaughter rate above 50%, ewes in estrus all year round, and lambing rate above 140%. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A technical roadmap for rapid breeding of new Tibetan sheep varieties provided by the present invention;

[0048] Figure 2 A population diagram of the Tibetan-Hu hybrid F1 sheep provided by the present invention;

[0049] Figure 3 A population diagram of the F1 generation of Australia-Lake hybrid sheep provided by the present invention;

[0050] Figure 4 A comparison chart of the birth weight of the F1 generation of Tibetan sheep hybridized with Aohu sheep and Tibetan sheep hybridized with Hu sheep provided by the present invention; the Tibetan sheep data is referenced from Mao Aihua, Li Hongmei, Zhang Hongxia, et al. Study on the reproductive performance of Oula-type Tibetan sheep ewes [J]. Journal of Animal Husbandry and Veterinary Medicine, 2017, 36(04): 7-9. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] Example

[0053] Rapid breeding of new Tibetan sheep breeds in a limited company in Minhe County, Qinghai Province and a professional cooperative in Huangyuan County:

[0054] (1) Selecting Australian White Sheep, Hu Sheep and Oula Sheep as parents with complementary advantages and outstanding production performance and genetic stability;

[0055] (2) Hybridization was performed with Australian white sheep as the male parent and Hu sheep as the female parent to produce the Australian Hu sheep hybrid F1 generation; then Hu sheep as the male parent and Tibetan sheep as the female parent were hybridized to produce the Tibetan Hu sheep hybrid F1 generation; the birth weight, number of siblings, multiple birth gene carrier status, coat color, and disease history of the hybrid F1 sheep were collected; the feeding management and disease prevention and control mode was the same as that of Tibetan sheep, with ewes grazing and lambs supplementary feeding;

[0056] (3) The F1 generation of Australian and Tibetan sheep hybrids were raised for grazing after weaning; the estrus frequency, disease history, coat color, and presence of horns of the F1 generation of Australian and Tibetan sheep hybrids were monitored at 6-8 months of age;

[0057] (4) Cross-breeding was performed using the F1 hybrid of Aohu sheep as the male parent and the F1 hybrid of Tibetan Hu sheep as the female parent, and the sheep were kept in grazing condition;

[0058] The selection criteria for the F1 generation of the Aohu hybrid are: birth weight ≥ 2.9kg, number of siblings ≥ 2, slender tail, FecB gene BB or B+ type, pure white coat, no horns, no history of disease; ewes are 7 months old, sexually mature, with normal udder and nipple hair and symmetrical structure; rams are 11 months old, sexually mature; rams have sperm motility higher than 78%, and sperm deformity rate lower than 14%;

[0059] The selection criteria for the F1 generation of the Tibetan-Hu hybrid are: birth weight ≥ 2.6kg, triangular tail, number of siblings ≥ 2, FecB gene type BB or B+, pure white coat, no horns, no history of disease; ewes are 7 months old, sexually mature, with normal udder and nipple hair and symmetrical structure; rams are 11 months old, sexually mature; rams have sperm motility higher than 78%, and sperm deformity rate lower than 14%;

[0060] (5) Use modern and efficient breeding technology of live egg collection from hybrid F1 sheep of Aohu and Zanghu, freezing of breeding sheep semen, in vitro embryo production, embryo transplantation and surrogacy. Starting from 8 months of age, superovulation is performed once a month, and live egg collection is performed using a live egg collection instrument and laparoscopy. Through in vitro maturation of oocytes, in vitro fertilization, in vitro embryo development and transplantation surrogacy technology, 10-15 live egg collections are performed on each breeding ewe, shortening the breeding cycle by 8-12 months, and each ewe produces more than 35 purebred offspring.

[0061] The breeding benefits of Tibetan sheep hybrid F1 and Tibetan sheep were compared. The breeding management, disease prevention and control and breeding mode of Tibetan sheep in pastoral areas are consistent. The specific comparison results are shown in Table 1 and Figure 2 to Figure 4 .

[0062] Table 1 Comparison of pure breeding and hybrid F generation breeding of Tibetan sheep in different seasons

[0063]

[0064] The results show that the new breed of Tibetan sheep can produce three lambs in two years, with a single-birth lambing rate that is more than 40% higher than that of the Oula sheep, and each breeding ewe can generate an additional annual profit of 650 yuan compared with the Oula sheep. The new breed shows good adaptability and stress resistance during the breeding process, significantly improving the production performance and economic benefits of local Tibetan sheep.

[0065] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for rapidly breeding a new breed of Tibetan sheep, characterized in that: The following steps are involved: (1) Using Australian White Sheep, Hu Sheep and Oula Sheep as parents; (2) hybridizing with Australian white sheep as the male parent and Hu sheep as the female parent to produce the Australian-Hu hybrid F1 generation; then hybridizing with Oula sheep as the male parent and Hu sheep as the female parent to produce the Tibetan-Hu hybrid F1 generation; (3) The F1 generation of Australian-Lake hybrid sheep and the F1 generation of Tibetan-Lake hybrid sheep were raised for grazing after weaning; (4) Using the F1 generation of Australia-Lake hybrid as the male parent and the F1 generation of Tibet-Lake hybrid as the female parent for cross-crossing, the cross-crossing obtains the F1 generation of Australia-Tibet-Lake cross-cross sheep, and maintains grazing and breeding; (5) Using the F1 generation of the Tibetan-Hu hybrid as the male parent and the F1 generation of the Australian-Hu hybrid as the female parent for cross-crossing, the Tibetan-Australian-Hu hybrid F1 generation sheep are obtained by cross-crossing, and the sheep are kept for grazing; (6) The F1 generation sheep obtained by cross-breeding between Ao-Zang-Hu and Zang-Ao-Hu were collected for birth weight, number of siblings, multiple birth gene carrier status, coat color and disease history; the feeding management and disease prevention and control mode was the same as that of Tibetan sheep, with ewes being grazed and lambs being supplemented with feed, and the F1 generation sheep of Ao-Zang-Hu were grazed after weaning; (7) Use the F1 generation of crossbreeding between Ao-Zang-Hu and Zang-Ao-Hu as the male and female parents for further crossbreeding and maintain the grazing mode; (8) The Ao-Tibetan Lake cross-cross F2 sheep obtained by cross-crossing collected the lactation performance of the Ao-Tibetan Lake cross-cross F1 ewes and the birth weight, number of siblings, multiparity gene carrier status, coat color and disease history of the cross-cross F2 sheep; the feeding management and disease prevention and control mode was the same as that of Tibetan sheep, with ewes grazing and lambs supplementary feeding, and the Ao-Tibetan Lake cross-cross F2 sheep were raised for grazing after weaning; (9) Repeating steps (7) and (8) until the Ao-Tibet Lake crossbreed F4 generation sheep is obtained, the excellent traits are finally fixed, and a purebred group is established; using modern and efficient breeding technologies such as live egg collection from Ao-Tibet Lake crossbreed F4 generation ewes, freezing of breeding sheep semen, in vitro embryo production, embryo transplantation and surrogacy, the herd is rapidly expanded to complete the rapid breeding of a new Tibetan sheep breed.

2. The method for rapidly breeding a new Tibetan sheep breed according to claim 1, characterized in that: In step (2), the following operations are performed on the hybrid F1 generation of Australian Hu sheep and the hybrid F1 generation of Tibetan Hu sheep: the birth weight, number of siblings, multiple birth gene carrier status, coat color and disease history of the hybrid F1 sheep are collected; the feeding management and disease prevention and control mode are the same as those of Tibetan sheep, with ewes grazing and lambs supplementary feeding.

3. The method for rapidly breeding a new Tibetan sheep breed according to claim 1, characterized in that: In step (3), the estrus frequency, disease history, coat color, and presence of horns of the F1 generation of the Australian-Lake hybrid and the Tibetan-Lake hybrid are monitored at 6-8 months of age.

4. The method for rapidly breeding a new Tibetan sheep breed according to claim 1, characterized in that: The selection criteria for the F1 generation of the Sino-Australian-Lake hybrid in step (4) are: birth weight ≥ 2.9 kg, number of siblings ≥ 2, slender tail, FecB gene of BB type or B+ type, pure white coat color, no horns, and no history of disease; ewes are 7 months old, sexually mature, with normal development of udders and nipples and symmetrical structure; rams are 11 months old, sexually mature; rams have sperm motility higher than 78%, and sperm deformity rate lower than 14%. The selection criteria for the F1 hybrid of Tibetan Hu sheep are: birth weight ≥ 2.6kg, triangular tail, number of siblings ≥ 2, FecB gene of BB or B+ type, white coat color, hornless, and no history of disease; ewes are 7 months old, sexually mature, with normal development of udders and nipples and symmetrical structure; rams are 11 months old, sexually mature; rams' sperm motility is higher than 78%, and sperm deformity rate is lower than 14%.

5. The method for rapidly breeding a new Tibetan sheep breed according to claim 1, characterized in that: The selection criteria for the F1 to F3 generation rams of the cross between the Australian Tibetan Lake and the Chinese-Australian Tibetan Lake in step (7) and step (9) are: birth weight ≥ 2.6 kg, number of siblings ≥ 2, slender tail, FecB gene of BB type, pure white coat color, no horns, no history of disease, symmetrical testicles, rams 11 months old, sexually mature; rams sperm motility higher than 78%, sperm deformity rate lower than 14%; The selection criteria for ewes are: birth weight ≧2.4kg, number of littermates ≧2, slender tail, FecB gene of BB type, pure white coat color, no horns, no history of disease, natural estrus symptoms monitored at 6 to 8 months of age, physical and sexual maturity at 7 months of age, normal udder and nipple hair, and symmetrical structure.

6. The method for rapidly breeding a new breed of Tibetan sheep according to claim 1, characterized in that: Step (8) The selection criteria for the F4 generation rams of the cross between China, Australia, Tibet and Lake are: solid physique, strong limbs, straight back, well-proportioned overall structure, slender tail, pure white coat, hornless, reaching physical and sexual maturity at 10 months of age, strong grazing, sociability and stress resistance, and FecB gene of BB type; The selection criteria for ewes are: moderately straight trunk, well-proportioned limbs, slender tail, pure white coat, no horns, some ewes have two "meat bells" on their necks, reach physical and sexual maturity at 7 months of age, strong grazing, sociability and stress resistance, lambing rate of more than 140%, estrus all year round, and FecB gene of BB type.

7. The method for rapidly breeding a new Tibetan sheep breed according to claim 1, characterized in that: In step (8), the core group of Australia-Tibet Lake cross F4 ewes are superovulated once a month starting from 12 months of age, and minimally invasive live egg collection is performed using a live egg collection instrument and laparoscopy. Through in vitro maturation of oocytes, in vitro fertilization, in vitro development of embryos and transplantation surrogacy technology, 10 to 15 live egg collections are performed on each breeding ewe, shortening the breeding cycle by 8 to 12 months, and each ewe produces more than 35 purebred offspring.

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