First, determine the correct breeding goal
1. Increase sow's reproductive rate and breeding rate (main election: raise the number of sows to be bred).
2. Increase the growth rate and feed utilization rate of finishing pigs (main election: increase daily weight gain).
3, improve the carcass lean meat and improve meat quality (main election: Carcass lean meat and meat quality).
At the same time, attention should also be paid to the shape consistency of the pigs, the number of nipples, the ulnar-feet traits and the improvement of resistance.
The growth and development (weight gain), carcass leanness, and meat quality of pigs are all high heritability traits and can be improved by breeding pig selection. However, the reproductive traits of the female raccoon is a low heritability trait, which is greatly influenced by environmental factors. It is necessary to adopt a large breeding population and a high selection difference to achieve progress. The effective methods of breeding in the world today are to improve heritability through high-quality breeding, and then to improve low heritability traits through crossbreeding (breeding or quality), and to adopt a combination of breeding and hybridization to increase the productivity of commercial pigs.
Second, the correct choice of parent varieties or strains
The only effective way to improve the breeding of commercial pigs is through hybridization on the basis of purebred breeding. The success or failure of hybrid production depends critically on the choice of hybrid parental variety or strain, as well as the right combination of crosses. The main choices in today's world for using paternal and maternal families are:
1. Paternal breeds: Main elections: Fast growth, high lean meat percentage, good meat quality.
(1) Duroc: Educated in the United States. The main feature is fast growth, followed by high lean meat. It has bright red flesh, large body size, strong physique, large feed intake, unrestricted feed selection, strong offspring ability, and good adaptability to the southern climate. At the same time, the hybridization effect is significant, which is the most widely used terminal hybridization in China. The main disadvantages are: fewer litters, shorter body, and more limbs.
(2) Hampshire: He was born in the United States. Main features: High lean meat ratio and large eye muscle area. After the introduction of our country, due to poor adaptability, the hybridization effect is not ideal, and it is rarely used in the hybridization father.
(3) Pitlan: native to Belgium. Main features: Short body size, well-developed body muscles, high lean meat ratio as high as 68 to 70% (76% reported separately), but fewer litters, poor meat quality, and stress, the effect of hybridization is better than lean meat. The descendants have short stature, low daily gain, and dark spots. The masses do not like it. At present, there are production Pi Du boars, which are hybridized with other female parents. According to experiments in Hubei and Guangxi, the litter size, weaning weight, and lean meat volume are similar to those of Duroc. However, the body is shorter and shorter, but the muscles are fuller. However, the export is not ideal.
In addition, there are Belgian Landrace pigs, Yorkshire pigs, Danish Landrace and Laguna pigs.
2. Maternal breeds: Main selection: Reproductive performance such as litter size and breeding.
(1) Landrace: Native to Denmark, the most representative is the Danish Landrace. Main features: Large numbers of litters (10.5～12), strong lactating capacity (more than 7kg in 28 days), fast growth, daily weight gain of 863-933g, lean meat ratio as high as 62%-64.4%, so This species can be used as a parent or as a parent. However, this species requires higher feeding conditions and more limb and foot disease.
(2) Yorkshire pigs: Bred in the United Kingdom. This kind of characteristics: First, there are many litters and 11 to 12 litters, and the second is that the daily weight gain is fast, and the lean percentage is 61~63% higher. It can be used as a parent or a parent. Compared with Landrace, Yorkshire has a stronger, more bearable body, but a slightly shorter body size than Landrace. In order to grow the sow's body, the long white male and female sows can be produced by crossbreeding with the Changbaigong.
Third, select the best pedigree and breeder individuals composed of purebred (pure) core groups
The core group is the core of the entire farm and is also the basis for improving the quality of cross-breeding pigs. Therefore, the ancestors and individuals must be carefully selected to form the core group according to the production records and the results of the measurements.
The first is the heritability of the selective pattern, followed by the selection of the difference. The intensity of selection mainly depends on the size of the selection group and the seed retention rate, and the reduction of the seed retention rate can increase the selection intensity.
IV. Purpose of Hybridization in the Production of Pigs
The first is the use of parental advantages. Hybridization superiority is the difference between the average phenotype of hybrid population traits and the mean value of the cross-parental population.
The second is to use the complementary properties of the parent's good traits.
You can choose binary hybridization, three-way hybridization, backcross mode. Ternary hybridization is better than binary crossbreeding. Quaternary two-hybrid can make full use of the advantages of hybridization of male and female hybrids and the complementarity of several pure line traits, but the common disadvantages of three-way and four-way hybrids require more parents and hybridization. The production and breeding system of male and female sows is complicated.
Five, supporting the basic steps of hybridization
1. After cultivating or determining the maternal cultivar and quality, select the best pedigree and strain for hybridization. From the maternity for the best maternity.
2, determine the paternal breeds, strains, generally through the determination of combining ability to see that the breed, the maternity line of the line and the breed, strains of the parent line of the best. The best standard is to determine the best combining ability based on the productivity after hybridization.
3. Test items for combining ability should include reproductive performance, fattening performance and slaughter performance, etc. It is also best to determine meat quality materials.
6. Duroc, Landrace, Yorkshire pigs select the main trait standard
1. Duroc:
Shape, brown hair red, no spotted. Thick head, slightly rooted ears, sagging ears, slightly reddish color, wide back and arch, thigh
Developed, plump, flat line, solid body, strong limbs.
Adult boars: Weight 220 kg or more, body height 90 cm, body length 175 cm or more.
Adult sows: weighing more than 200 kilograms, body height 85 cm, body length 165 cm or more.
Production performance: number of litters: 8 to 10 heads, fattening pigs (25 to 90 kg) daily gains of 650 to 700 grams or more, lean meat ratio of 63% or more.
2. Landrace:
Appearance: All white, light and long, straight face, ear forward drooping, body length, back width, well-developed thighs, flat belly lines,
Nipple 7 pairs, thin skin, fine bones, delicate appearance, a defensive appearance.
Adult boars: 200 kg or more in weight, 180 cm in length and 80 cm in height.
Sows: Weight more than 100 kilograms, body length 170 cm above body height 75 cm.
Production performance: 11 to 12 litter size pigs, finishing pigs daily gain (25 to 90 kilograms) over 650 grams on average, lean meat ratio of 62% or more.
3, Yorkshire pigs:
Appearance: All white, tall body, long head, surface dimples, erect ears, back waist wide, thigh development, multiple lines, high and strong limbs.
Adult boars: Weight 220 kg or more, body length 175 cm, body height 85 cm or more.
Adult sows: 200 kg body weight, body length 165 cm, body height 80 cm or more.
Production performance: 11 to 12 litter size, fattening pigs gain more than 700 grams per day, and the lean meat rate is over 62%.
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