Method for breeding a new breed of dual-purpose sheep

Abstract

This invention discloses a method for breeding a new dual-purpose (meat and milk) sheep breed. The method involves crossbreeding East Friesian sheep as the sire and Lowland sheep as the dam to obtain the East F1 generation; crossbreeding the East F1 generation with Lowland sheep as the dam to obtain the East F2 generation; crossbreeding the East F1 generation with East Friesian sheep as the dam to obtain the East F2 generation flock; and crossbreeding the East F2 generation with East F1 generation as the dam and Lowland sheep as the dam to obtain the East F3 generation flock. Superior rams and ewes from the East F3 generation flock are selected for self-pollination to establish a zero-generation dual-purpose sheep flock. Through crossbreeding fixation, generational selection, and breeding expansion, a new dual-purpose sheep breed is developed. The new breed developed by this invention has advantages such as good meat performance, excellent milk production performance, high fertility, good maternal instincts, and strong adaptability.

Description

Technical Field

[0001] This invention belongs to the field of animal breeding technology, specifically relating to a method for breeding a new breed of dual-purpose (meat and milk) sheep. Background Technology

[0002] In recent years, as the nutritional and health benefits of sheep milk have been developed, people have gradually recognized that sheep milk has a higher nutritional value than cow milk. Sheep milk has a lower casein content and a higher content of unsaturated fatty acids. Its fat globules and protein particles are only 1 / 3 the size of those in cow milk, making it easier for the human body to digest and absorb. In addition, sheep milk is rich in epidermal growth factor, essential amino acids, and high-quality proteins (lysine, methionine, isoleucine, leucine, phenylalanine, valine, threonine, albumin, globulin, etc.) that are the same as those in breast milk. Therefore, sheep milk is regarded as a "premium dairy product" and is hailed as the "king of milk" by the international nutrition community.

[0003] Dairy sheep, a niche and distinctive industry within the global livestock system, account for less than 5% of the total sheep population but support 15%-20% of the supply demand in the world's high-end dairy product industry chain (such as French Rockford cheese, Italian Pecorino cheese, and Turkish yogurt). Currently, livestock powerhouses such as France, the UK, Israel, and Australia have successively developed specialized dairy sheep breeds such as East Friesian, Lacounste, British dairy sheep, and Asaf. Compared to traditional local sheep breeds, specialized dairy sheep breeds increase milk production to 800-1200 liters per year (some breeds can reach 1500 liters), and extend the lactation period by 2-3 months, greatly increasing sheep milk production.

[0004] It is understood that my country has 106 sheep breeds, but specialized dairy sheep breeds are still lacking, and dairy sheep breeds and sheep dairy products are basically dependent on imports. In recent years, with the vigorous development of my country's meat sheep industry, the sheep farming structure has undergone a major adjustment, gradually shifting from wool-producing to meat- and dairy-producing. Therefore, developing new dual-purpose (meat and dairy) sheep breeds is not only a requirement for the development of my country's sheep industry, but also an urgent need to enrich my country's dairy product market. Summary of the Invention

[0005] This invention addresses the technical problem by overcoming the shortcomings of existing technologies and provides a method for breeding a new dual-purpose (meat and milk) sheep breed. The new breed developed using this method possesses advantages such as excellent meat performance, high milk production, high fertility, good maternal instincts, and strong adaptability. Adult rams weigh 80-90 kg, and adult ewes weigh 55-65 kg. A single lactation cycle produces over 155 kg of milk with a protein content of 5.5%-6.0%, a fat content of 6.0%-6.5%, and a lambing rate exceeding 235%. Compared to East Friesian sheep, this invention significantly improves meat performance, reproductive performance, milk production, protein content, and fat content. It also overcomes the general adaptability limitations of East Friesian sheep, making it suitable for the feeding conditions in different regions of my country.

[0006] To promote the high-quality development of my country's sheep breeding industry, this invention proposes a method for breeding a new dual-purpose (meat and milk) sheep breed. By introducing East Friesian sheep bloodlines, the invention crossbreeds and improves the unique local sheep breed of Wadi Sheep in my country, providing a reference for the breeding of dual-purpose (meat and milk) sheep breeds in my country.

[0007] The purpose of this invention is to provide a method for breeding a new dual-purpose (meat and milk) sheep breed, characterized by comprising the following steps: (1) Using East Frisen sheep as the original paternal parent and lowland sheep as the original maternal parent, crossbreeding was carried out to obtain the East Lowland F1 generation sheep flock; (2) Crossbreeding the ewes in the Dongwa F1 generation sheep flock with the ewes in the depression sheep flock with the sires to obtain the Dongwa F2 generation sheep flock; crossbreeding the ewes in the Dongwa F1 generation sheep flock with the ewes in the Dongwa F1 generation sheep flock with the sires in the Dongfried sheep flock with the sires to obtain the Dongwa F2 generation sheep flock. (3) Crossbreeding was carried out using ewes from the F2 generation of the Dongwa sheep flock as the female parent and rams from the F1 generation of the Dongwa sheep flock as the male parent, and crossbreeding was carried out using ewes from the F2 generation of the Dongwa sheep flock as the female parent and ewes from the Wadi sheep flock as the male parent, to obtain the F3 generation of the Dongwa sheep flock. (4) Select outstanding rams and ewes from the F3 generation sheep flock in Dongwa for self-crossing to form a zero-generation flock of dual-purpose (meat and milk) sheep. Through cross-crossing fixation, generational selection and breeding, and expansion of the flock, a new breed of dual-purpose (meat and milk) sheep was developed.

[0008] The new breed of this invention contains 37.5% East Friesian sheep bloodline and 62.5% lowland sheep bloodline.

[0009] The further optimized technical solution of this invention is as follows: The present invention relates to a method for breeding a new dual-purpose (meat and milk) sheep breed, which specifically includes the following steps: Breeding of the Dongwa F1 generation sheep flock: ①The East Friesian sheep were used as the original paternal line and the lowland sheep were used as the original maternal line to crossbreed the East Friesian sheep to obtain the East Friesian F1 generation sheep flock. The East Friesian F1 generation sheep flock contains 50% East Friesian sheep bloodline and 50% lowland sheep bloodline. ② The selection criteria for the Dongwa F1 generation rams include: carrying at least one copy of the FecB gene, having a birth weight of over 3.5 kg, fast growth rate, and strong disease resistance; the selection criteria for the Dongwa F1 generation ewes include: carrying at least one copy of the FecB gene, having a birth weight of over 2.2 kg, well-developed udders, producing over 170 kg of milk per lactation cycle, with a milk protein content of over 5.4% and a milk fat content of over 6.1%; Breeding of F2 generation sheep flocks in Wadongwa: ① Using selected ewes from the Dongwa F1 generation sheep flock as the maternal line and Wadi sheep as the paternal line, crossbreeding was carried out to obtain the Dongwa F2 generation sheep flock. The Dongwa F2 generation sheep flock contains 25% East Frisian sheep bloodline and 75% Wadi sheep bloodline. ② All male sheep in the F2 generation of the Wadongwa sheep flock were culled. The selection criteria for the F2 generation of female sheep in the Wadongwa sheep flock included: carrying two copies of the FecB gene, birth weight of more than 2.1 kg, good udder development, milk production of more than 135 kg per lactation cycle, milk protein content of more than 5.1%, and milk fat content of more than 6.0%. Breeding of the Dongwa F2 generation sheep flock: ① The selected ewes from the Dongwa F1 generation sheep flock were used as the maternal line and the Dong Friesian sheep were used as the paternal line to crossbreed the Dongwa F2 generation sheep flock. The Dongwa F2 generation sheep flock contained 75% Dong Friesian sheep bloodline and 25% Wudi sheep bloodline. ② All male sheep in the Dongwa F2 generation flock were culled. The selection criteria for the Dongwa F2 generation female sheep flock included: carrying two copies of the FecB gene, birth weight of more than 2.3 kg, good udder development, milk production of more than 180 kg per lactation cycle, milk protein content of more than 5.3%, and milk fat content of more than 6.3%. Breeding of the Dongwa F3 generation sheep flock: ① Crossbreeding was carried out using ewes from the F2 generation of the Dongwa sheep flock as the maternal line and rams from the F1 generation of the Dongwa sheep flock as the paternal line. At the same time, crossbreeding was carried out using selected ewes from the F2 generation of the Dongwa sheep flock as the maternal line and wadi sheep as the paternal line to obtain the F3 generation of the Dongwa sheep flock. The F3 generation of the Dongwa sheep flock contains 37.5% East Friesian sheep bloodline and 62.5% wadi sheep bloodline. ② The selection criteria for the F3 generation rams in Dongwa include: carrying two copies of the FecB gene, having a birth weight of over 3.2 kg, fast growth rate, and strong disease resistance; the selection criteria for the F3 generation ewes in Dongwa include: carrying two copies of the FecB gene, having a birth weight of over 2.15 kg, good udder development, producing over 150 kg of milk per lactation cycle, with a milk protein content of over 5.4% and a milk fat content of over 6.1%; Development of new dual-purpose (meat and milk) sheep breeds: ① Select outstanding rams and ewes from the F3 generation sheep flock in Dongwa to form a zero-generation flock of dual-purpose (meat and milk) sheep. Use the group successive generation selection method to crossbreed and fix the sheep for four generations. Select a group with stable meat traits, reproductive traits, milk secretion traits and stress resistance traits for self-crossing, and finally breed a new breed of dual-purpose (meat and milk) sheep. ② The selection criteria for dual-purpose (meat and milk) sheep rams in the zero generation include: carrying two copies of the FecB gene, having a birth weight of over 3.4 kg, fast growth rate, and strong disease resistance; the selection criteria for dual-purpose (meat and milk) sheep ewes in the zero generation include: carrying two copies of the FecB gene, having a birth weight of over 2.2 kg, well-developed udder, producing over 155 kg of milk per lactation cycle, with a milk protein content of over 5.5% and a milk fat content of over 6.2%.

[0010] Preferably, the selection criteria for the sire, East Friesian sheep, are: adult weight of 90-100 kg, white coat all over the body, thin skin, white with a slight pink tinge, large body size, sturdy physique, long and thin tail, and well-developed testes.

[0011] Preferably, the selection criteria for female sheep from low-lying areas are: adult weight of 55-65kg, hornless, slightly raised nasal bridge, large and slightly drooping ears, small head and long neck, straight back and loin, narrow chest, well-developed hindquarters, hard hooves, well-developed udder, and an average lambing rate of over 240%.

[0012] Preferably, the selection criteria for sire sheep from low-lying areas are: adult weight of 70-80 kg, hornless, slightly raised nasal bridge, large and slightly drooping ears, large head and thick neck, straight back and loin, narrow chest, well-developed hindquarters, hard hooves, and well-developed testes.

[0013] In this invention, cross-fixation is performed using phenotypic selection and FecB gene detection technology.

[0014] The new dual-purpose sheep breed developed using the method of this invention has a white coat, good body structure, and advantages such as good meat performance, excellent milk production, high fertility, good maternal instincts, and strong adaptability. Adult rams weigh 85-95 kg, and adult ewes weigh 60-70 kg. A single lactation cycle produces over 155 kg of milk, with a milk protein content of 5.0%-5.5%, a milk fat content of 6.0%-6.5%, and a lambing rate of over 155%. Compared with the East Friesian sheep, this new dual-purpose sheep breed shows significant improvements in meat performance, milk production, milk protein content, and milk fat content. It also overcomes the poor adaptability of the East Friesian sheep, making it suitable for different feeding conditions in various regions of my country. Furthermore, the breeding process uses a dual-track approach, supplemented by FecB gene selection technology, which greatly accelerates generational progress and breeding speed, avoiding excessive inbreeding and resulting in excellent potential for widespread adoption.

[0015] The breeding method of this invention can breed a new dual-purpose sheep breed with high meat and milk production, stable performance, good adaptability and high reproductive capacity, solving the technical problem that there is currently no dual-purpose sheep breed, and has great potential for promotion. Attached Figure Description

[0016] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0017] The technical solution of the present invention will be further described in detail below with reference to the embodiments: This embodiment is implemented under the premise of the technical solution of the present invention, and provides detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0018] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0019] Unless otherwise specified, the reagents and materials involved in the following examples can be obtained by the public from domestic and foreign commercial channels or other free channels, and will not be described in detail here. Example

[0020] The breeding method for a new dual-purpose (meat and milk) sheep breed in this embodiment mainly includes the following steps: (1) Select 20 healthy and excellent East Friesian rams as sires and 4,000 healthy and excellent lowland sheep ewes as dams. The selection criteria for East Friesian rams are: adult weight of 90-100 kg, white wool all over the body, thin skin, white with a slight pink tinge, large body size, strong physique, long and thin tail, and well-developed testes; the selection criteria for lowland sheep ewes are: adult weight of 45-55 kg, white wool all over the body, long and narrow head with a prominent nasal bridge, long and thin neck, straight back and waist, long and narrow body, slightly drooping abdomen, well-developed udder, and an average lambing rate of over 250%.

[0021] Crossbreeding was carried out using selected East Friesian sheep as the sire and Lowland sheep as the dam. 50 superior rams and 2,000 superior ewes were selected from the offspring to obtain the East Lowland F1 generation flock. The F1 generation contains 50% East Friesian sheep bloodline and 50% Lowland sheep bloodline.

[0022] The selection criteria for the Dongwa F1 generation rams include: carrying at least one copy of the FecB gene, a birth weight of over 3.5 kg, rapid growth, and strong disease resistance. The selection criteria for the Dongwa F1 generation ewes include: carrying at least one copy of the FecB gene, a birth weight of over 2.2 kg, well-developed udders, a milk yield of over 170 kg per lactation cycle, a milk protein content of over 5.4%, and a milk fat content of over 6.1%.

[0023] (2) Select 10 healthy and excellent rams from the lowland sheep as sires. The selection criteria for sires from the lowland sheep are: adult weight of 75-85kg, white fur all over the body, long and narrow head with a prominent nasal bridge, long and thin neck, straight back and waist, long and narrow body, slightly drooping abdomen, and well-developed testes.

[0024] Using the selected lowland sheep as the sires and 1000 selected ewes from the Dongwa F1 generation as the dams, crossbreeding was conducted. All rams were culled, and 1000 superior ewes were selected to form the Dongwa F2 generation sheep flock. The Dongwa F2 generation sheep flock contains 25% East Friesian sheep bloodline and 75% lowland sheep bloodline. The selection criteria for the Dongwa F2 generation ewes included: carrying two copies of the FecB gene, a birth weight of over 2.1 kg, well-developed udders, a milk yield of over 135 kg per lactation cycle, a milk protein content of over 5.1%, and a milk fat content of over 6.0%.

[0025] (3) Ten healthy and excellent East Friesian rams were selected as sires, and 1,000 selected ewes from the Dongwa F1 generation were selected as dams for crossbreeding to obtain the Dongwa F2 generation. The Dongwa F2 generation contained 75% East Friesian bloodline and 25% Dongwa sheep bloodline. All rams in the Dongwa F2 generation were culled. The selection criteria for the Dongwa F2 generation ewes included: carrying two copies of the FecB gene, birth weight of more than 2.3 kg, well-developed udder, milk production of more than 180 kg per lactation cycle, milk protein content of more than 5.3%, and milk fat content of more than 6.3%.

[0026] (4) Using 1000 ewes from the selected Dongwa F2 generation sheep flock as the maternal line and 10 rams from the Dongwa F1 generation sheep flock as the paternal line, crossbreeding was carried out. From the resulting offspring, 100 superior rams and 1000 superior ewes were selected. In addition, using 1000 ewes from the selected Dongwa F2 generation sheep flock as the maternal line and 10 Wadi sheep as the paternal line, crossbreeding was carried out. From the resulting offspring, 100 superior rams and 1000 superior ewes were selected. The Dongwa F3 generation sheep flock was formed from the above-selected sheep flocks. The Dongwa F3 generation sheep flock contained 37.5% East Friesian sheep bloodline and 62.5% Wadi sheep bloodline. The selection criteria for the Dongwa F3 generation ewe flock include: carrying two copies of the FecB gene, birth weight of more than 2.15 kg, good udder development, milk production of more than 150 kg per lactation cycle, milk protein content of more than 5.4%, and milk fat content of more than 6.1%.

[0027] (5) Select 100 outstanding rams and 1000 ewes from the F3 generation of the Dongwa sheep flock to form a zero-generation dual-purpose sheep flock. Use the group successive generation selection method to crossbreed and fix the sheep for four generations. Select a group with stable meat traits, reproductive traits, lactation traits, and stress resistance traits for self-pollination to finally develop a new breed of dual-purpose sheep. The selection criteria for the zero-generation ram flock of dual-purpose sheep include: carrying two copies of the FecB gene, a birth weight of more than 3.4 kg, fast growth rate, and strong disease resistance. The selection criteria for the zero-generation ewes flock of dual-purpose sheep include: carrying two copies of the FecB gene, a birth weight of more than 2.2 kg, fast growth rate, strong disease resistance, good udder development, milk production of more than 155 kg per lactation cycle, milk protein content of more than 5.5%, and milk fat content of more than 6.2%.

[0028] In this embodiment, cross-fixation was performed using phenotypic selection and FecB gene detection technology.

[0029] The new dual-purpose (meat and milk) sheep breed developed by the method of this invention has a white coat, good body structure, and advantages such as good meat performance, excellent milk production, high fertility, good maternal instincts, and strong adaptability. Adult rams weigh 80-90 kg, and adult ewes weigh 55-65 kg. They produce over 155 kg of milk per lactation cycle, with a milk protein content of 5.5%-6.0%, a milk fat content of 6.0%-6.5%, and a lambing rate of over 235%. Table 1 compares the performance indicators of the developed dual-purpose sheep with those of the other breeds used in the breeding.

[0030] Table 1. Comparison of performance indicators of dual-purpose (meat and milk) dairy sheep with those of participating breeds

[0031] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any transformations or substitutions that can be conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for breeding a new dual-purpose (meat and milk) sheep breed, characterized in that, Includes the following steps: (1) Using East Frisen sheep as the original paternal parent and lowland sheep as the original maternal parent, crossbreeding was carried out to obtain the East Lowland F1 generation sheep flock; (2) Crossbreeding the ewes in the Dongwa F1 generation sheep flock with the ewes in the depression sheep flock with the sires to obtain the Dongwa F2 generation sheep flock; crossbreeding the ewes in the Dongwa F1 generation sheep flock with the ewes in the Dongwa F1 generation sheep flock with the sires in the Dongfried sheep flock with the sires to obtain the Dongwa F2 generation sheep flock. (3) Crossbreeding was carried out using ewes from the F2 generation of the Dongwa sheep flock as the female parent and rams from the F1 generation of the Dongwa sheep flock as the male parent, and crossbreeding was carried out using ewes from the F2 generation of the Dongwa sheep flock as the female parent and ewes from the Wadi sheep flock as the male parent, to obtain the F3 generation of the Dongwa sheep flock. (4) Select outstanding rams and ewes from the F3 generation sheep flock in Dongwa for self-crossing to form a zero-generation flock of dual-purpose (meat and milk) sheep. Through cross-crossing fixation, generational selection and breeding, and expansion of the flock, a new breed of dual-purpose (meat and milk) sheep was developed.

2. The method for breeding a new dual-purpose (meat and milk) sheep breed according to claim 1, characterized in that, Includes the following steps: Breeding of the Dongwa F1 generation sheep flock: ①The East Friesian sheep were used as the original paternal line and the lowland sheep were used as the original maternal line to crossbreed the East Friesian sheep to obtain the East Friesian F1 generation sheep flock. The East Friesian F1 generation sheep flock contains 50% East Friesian sheep bloodline and 50% lowland sheep bloodline. ② The selection criteria for the Dongwa F1 generation rams include: carrying at least one copy of the FecB gene, having a birth weight of over 3.5 kg, fast growth rate, and strong disease resistance; the selection criteria for the Dongwa F1 generation ewes include: carrying at least one copy of the FecB gene, having a birth weight of over 2.2 kg, well-developed udders, producing over 170 kg of milk per lactation cycle, with a milk protein content of over 5.4% and a milk fat content of over 6.1%; Breeding of F2 generation sheep flocks in Wadongwa: ① Using selected ewes from the Dongwa F1 generation sheep flock as the maternal line and Wadi sheep as the paternal line, crossbreeding was carried out to obtain the Dongwa F2 generation sheep flock. The Dongwa F2 generation sheep flock contains 25% East Frisian sheep bloodline and 75% Wadi sheep bloodline. ② All male sheep in the F2 generation of the Wadongwa sheep flock were culled. The selection criteria for the F2 generation of female sheep in the Wadongwa sheep flock included: carrying two copies of the FecB gene, birth weight of more than 2.1 kg, good udder development, milk production of more than 135 kg per lactation cycle, milk protein content of more than 5.1%, and milk fat content of more than 6.0%. Breeding of the Dongwa F2 generation sheep flock: ① The selected ewes from the Dongwa F1 generation sheep flock were used as the maternal line and the Dong Friesian sheep were used as the paternal line to crossbreed the Dongwa F2 generation sheep flock. The Dongwa F2 generation sheep flock contained 75% Dong Friesian sheep bloodline and 25% Wudi sheep bloodline. ② All male sheep in the Dongwa F2 generation flock were culled. The selection criteria for the Dongwa F2 generation female sheep flock included: carrying two copies of the FecB gene, birth weight of more than 2.3 kg, good udder development, milk production of more than 180 kg per lactation cycle, milk protein content of more than 5.3%, and milk fat content of more than 6.3%. Breeding of the Dongwa F3 generation sheep flock: ① Crossbreeding was carried out using ewes from the F2 generation of the Dongwa sheep flock as the maternal line and rams from the F1 generation of the Dongwa sheep flock as the paternal line. At the same time, crossbreeding was carried out using selected ewes from the F2 generation of the Dongwa sheep flock as the maternal line and wadi sheep as the paternal line to obtain the F3 generation of the Dongwa sheep flock. The F3 generation of the Dongwa sheep flock contains 37.5% East Friesian sheep bloodline and 62.5% wadi sheep bloodline. ② The selection criteria for the F3 generation rams in Dongwa include: carrying two copies of the FecB gene, having a birth weight of over 3.2 kg, fast growth rate, and strong disease resistance; the selection criteria for the F3 generation ewes in Dongwa include: carrying two copies of the FecB gene, having a birth weight of over 2.15 kg, good udder development, producing over 150 kg of milk per lactation cycle, with a milk protein content of over 5.4% and a milk fat content of over 6.1%; Development of new dual-purpose (meat and milk) sheep breeds: ① Select outstanding rams and ewes from the F3 generation sheep flock in Dongwa to form a zero-generation flock of dual-purpose (meat and milk) sheep. Use the group successive generation selection method to crossbreed and fix the sheep in four generations. Select a group with stable meat traits, reproductive traits, milk secretion traits and stress resistance traits for self-pollination, and finally breed a new breed of dual-purpose (meat and milk) sheep. ② The selection criteria for dual-purpose (meat and milk) sheep rams in the zero generation include: carrying two copies of the FecB gene, having a birth weight of over 3.4 kg, fast growth rate, and strong disease resistance; the selection criteria for dual-purpose (meat and milk) sheep ewes in the zero generation include: carrying two copies of the FecB gene, having a birth weight of over 2.2 kg, well-developed udder, producing over 155 kg of milk per lactation cycle, with a milk protein content of over 5.5% and a milk fat content of over 6.2%.

3. The method for breeding a new dual-purpose (meat and milk) sheep breed according to claim 1 or 2, characterized in that, The selection criteria for sires of East Friesian sheep are: adult weight of 90-100 kg, white coat all over the body, thin skin, white with a slight pink tinge, large body size, sturdy physique, long and thin tail, and well-developed testes.

4. The method for breeding a new dual-purpose (meat and milk) sheep breed according to claim 1 or 2, characterized in that, The selection criteria for female sheep from the low-lying areas are: adult weight of 55-65kg, hornless, slightly raised nasal bridge, large and slightly drooping ears, small head and long neck, straight back and loin, narrow chest, well-developed hindquarters, hard hooves, well-developed udder, and an average lambing rate of over 240%.

5. A method for breeding a new dual-purpose (meat and milk) sheep breed according to claim 1 or 2, characterized in that, The selection criteria for sire sheep from the low-lying areas are: adult weight of 70-80kg, hornless, slightly raised nasal bridge, large and slightly drooping ears, large head and thick neck, straight back and loin, relatively narrow chest, well-developed hindquarters, hard hooves, and well-developed testes.

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