The significance and breeding characteristics of high quality broilers
First, the significance of quality broiler
In recent years, more and more attention has been paid to quality broilers both at home and abroad, and a great deal of research has been conducted.
What is a high-quality broiler? In foreign countries, high-quality broilers are basically only for the so-called quality, the English name translated into qualitymeat-chicken or highqualitymeat-chicken. The consideration of feather color mainly depends on whether it affects the appearance of the carcass after slaughter, and therefore likes white feathers. The consideration of the size of the crotch is mainly based on whether or not the crotch is capable of supporting the fast growing body. As for which kind of feather color and which kind of chickens are better eaten, they do not seem to be interested. In China, where there are different places and different starting points, there are various understandings of quality broilers. Therefore, the significance of high quality broilers is also different.
1. Nutritional Significance: A broiler that is good for human health is called a good broiler. It requires high muscle protein content, amino acid balance and in line with the needs of the human body, can supplement metabolic consumption, regulate physiological function, promote the healthy development of the human body; on the other hand, require muscle and other tissues and organs containing moderate fat, low cholesterol, no residue Drugs and poisons.
2. Product Significance: Many people in many provinces and cities in Guangdong and China say that yellow chicken and hemp chicken are high quality broilers. These broilers are moderately sized with four yellow or three yellow hemp (feather yellow or hemp, pimple, feet, skin yellow), three fine (head, feet, bones fine), four short (neck, body, tail, short legs) The characteristics of the crown red, carcass appearance, small pores, thin skin, no trauma and so on.
3. Meaning of consumption: The chickens eaten by the food and the public are good quality broilers. The chickens have a long feeding time, moderate muscle and fat ratios, certain subcutaneous and intermuscular fat, fine muscle fibers, tender and delicate meat, and delicious meat. The chicken is thick and has a good taste.
4. Traditional meaning: With the improvement of living standards, the people's taste is retro, traditional chicken is regarded as the top grade, so some people think that high-quality broiler is local chicken. This kind of local chicken breeds in our country, yellow and red plumes are more considered as the symbol of Geely, and white feathers are hard to accept.
5. Production Significance: Chickens produced with the lowest cost and most convenient process are quality broilers. Such as low feed consumption, rapid growth, good uniformity, slaughtering and processing, carcass aesthetics, high slaughter rate, low prices and high profits. For example, some large-scale broiler chickens imported from abroad can be slaughtered in 40-50 days. The ratio of meat to meat is 1:2. The production cycle is short and the capital turnover is fast.
The above-mentioned several kinds of meanings are not very scientific and comprehensive. At present, domestically preferred high-quality broilers are characterized by the above-mentioned second and third points, and are generally kept for 60-110 days, and the weight is 1.2-2.0. Kilograms of yellow, hemp chicken. It should be pointed out that this universal division does not mean to degrade other chickens, mainly by following people's customary terms.
Second, the assessment of chicken meat quality
The significance of the above-mentioned quality broilers is varied, and therefore the evaluation method is naturally different for the superiority and inferiority of chicken meat quality.
The assessment of chicken quality is a complex concept. In the narrow sense, it refers to people's feelings and evaluations of chicken's color, smell and taste. The quality assessment in the broad sense includes comprehensive evaluation and determination of the flavor, nutritional value and various physical and chemical characteristics of chicken meat.
In general, meat quality can be assessed both rationally and emotionally, that is, objectively and subjectively.
1. Objective criteria: The assessment is made on physical and chemical properties. Physical properties include water retention, tenderness, shear, tissue structure, and collagen content. Chemical properties include pH, fatty acids, amino acids, flavor components, residues, poisons, and more. The above characteristics have specific measurement methods both at home and abroad, and some universities and scientific research departments in the province can conduct measurements.
2. Subjective criteria: subjective criteria refer to subjective evaluation through the eyes, nose, and mouth, based on the appearance of the chicken and the taste of its taste. The assessment is based on color, smell, taste, and type. There is no unified standard and there is no special meat and meat agency. Of course, this assessment is not arbitrary and isolated, there is a very close relationship between sensory evaluation and rational characteristics, and it reflects the superiority of chicken quality to a large extent.
Third, the breeding of high quality broilers
The breeding of high-quality broilers mainly targets breeders, ie, the original breeder, the ancestor, the parental generation, etc. Through breeding these breeders, the results of breeding are finally reflected in the merchandise generation.
1. Objective objective of high quality broiler breeding
(1) Through breeding, the breeder must achieve the following basic requirements: 1 Wide adaptability, strong disease resistance, resistance to roughage, and easy management; 2 High uniformity of the group; 3 Good production efficiency and economic benefits.
(2) Through breeding, the chickens produced must meet the following basic requirements: 1 Wide applicability, strong disease resistance, and easy management; 2 Highly-ordered groups and good production efficiency; 3 Thin and thin bones and meat Fine, small muscle fibers, moderate intermuscular fat; 4 delicious meat, strong chicken taste, good taste, and some of the ingredients related to good flavor content; 5 high protein content, amino acid species and more balanced; 6 suitable for a variety of Cooking.
2. Breeding characteristics of high-quality broilers (1). Feather: Although there is no specific relationship between chicken feather color and chicken germplasm, chicken nutrition and taste, due to the market of live chickens, consumers prefer yellow or yellow feathers. In many places, the concept of three yellow chickens and high quality broilers is usually the same. Therefore, in the breeding of high-quality broilers, feather selection should be given full attention, and the preferred breeding traits are yellow (or hemp) feathers. Individual selection can play a greater role, that is, pure yellow feathers or hemp feathers are selected from the phenotype, adopting closed population breeding methods, and homogenous matching. After several generations, the consistency of the group's coat color is improved. In particular, for the flocks with more mixed feathers (such as hemp, black, brown, white, reed colors, etc.), the closed population breeding method is more conducive to the further homozygosis of white and other variegated colors. The chance of exposure, and then through the phenotypic selection, all out of the feathered individual. It is also sometimes possible to remove variegated genes from genotypes by means of test-crossing.
(2) Body traits: There are three types of broilers: large, medium, and small, of which the small high-quality yellow (hemp) broiler has a higher economic value. The broiler's body type should be selected according to different breeds and different consumption habits. Regardless of body type, it is required that the head is small, the neck is short, the chest is wide, the cymbal is short, the cymbal is fine, and the corpus callosum is full. For the length, thickness and color of the cockroaches, the selection method is to select individuals with appropriate body weight, and then select individuals with short, fine, and yellowish colors from among them, among which the selection criteria for cock cockroaches should be appropriately lowered to ensure Roosters have sufficient body weight, while hens increase their selection pressure and try to select individuals who are short and fine. A corresponding reduction in body weight is also permissible because hen weights have a relatively small impact on offspring. In addition to body size and length, thickness and color of the cormorants, each generation is selected to stay crown red, moderate body length, short tail, hairy and shiny individuals, and accordingly adhere to eliminate the body too narrow, tail too wings, feathers Fluffy individual.
(3) Meat quality traits: The meat quality is determined mainly by the variety. Fine chickens with fine muscle fibers and small muscle bundles are preferred. Medium and slow large breeds meet the requirements. After 90-130 days of feeding, the skin is thin and the muscles are tender. Slippery, subcutaneous and intermuscular fat distribution, suitable for all kinds of cooking, especially for the production of white chicken, salt chicken. The effect of breeding on meat quality is limited in a short period of time. We cannot expect to use a few years to transform a large variety introduced from foreign countries into a variety of delicate muscle fibers and rich chicken flavor. In other words, it is important to focus on the situation and avoid detours. Replace chickens that are not expected at high levels as soon as possible. In addition, reasonable measures such as feeding and management are also necessary, because meat quality is affected by various factors such as feed, age, sex, and slaughter and processing.
(4) Growth rate and feed conversion rate: The chicken with tender meat and chicken with strong chicken taste has slow growth rate and low feed conversion rate. In order to meet the needs of commodity production, the growth performance of high quality broilers must be properly selected and not obvious. In the case of affecting meat quality, the effect of increasing the weight gain rate and feed reward can be achieved. The main choice is individual selection. When hatching, choose large heads with large necks, flat rounds with navels, healthy and strong chicks, pick out weak individuals, and generally select 10%. Male and female chickens were selected three times at different ages, 28 days, 70 days, and 90 days. The hens selected individuals with moderate body weight, good health development, good body shape, and compact coats, and the number of selected hens was 60%-70% of the number of hens hatched. Roosters were selected as individuals with good growth, good body appearance, strong bones, strong ankles, large crowns, bright eyes, weights above the mean plus one standard deviation, and 20% of the number of cock chicks.
(5) Utilization of Dwarf Genes: The sex dw gene dw can reduce the body size of chicken without significantly affecting chicken viability and productivity, and it can also reduce production costs. When using dwarf genes in high-quality broiler breeding, care should be taken as close as possible to the type of target that the local consumer thinks. Usually the first generation is crossed by a normal type and a dwarf minitype, and then the target size is used. Hybrids are good once.
(6) Newborn chickens are self-sufficient: In some places, high-quality broilers are usually only for hens. This type of meat cockerel has a low price because of slow growth. Farmers do not like raising the hatchery or breeder farm. Had to sell at low prices or for fish farming. Therefore, it is more important to identify the sex of chicks than other species on the first day. In the breeding of high-quality broilers, sex-linked fast and slow feather genes can be used to breed male-female strains.
The type of feather speed is controlled by a pair of genes (k, K) at the same locus, in which the slow feather gene K is dominant, the fast feather gene k is recessive, and the fast feather chicken genotype is ZkZk and ZkW, manifested as the main wing when hatching. The feathers are longer than the main wing feathers. The main wing feathers are shorter than the main wing feathers or not. The slow chicken genotypes were ZKZK, ZKZk and ZKW, which showed that the main wing feathers were shorter than or equal to the main wing feathers or the main wing feathers were not grown when hatching. For each group of chicks, pigeons were identified within 24 hours of shelling, and the fast and slow feathers were separated. After a certain breeding program, a pure and fast plume is established within 2-3 generations, and the male and female self-divided lines are established through appropriate matching.
It must be noted that according to local consumption habits, the relationship between speed and speed of feathering and feather growth, and the degree of feather coverage should be properly addressed.
(7) Selection of reproductive performance: Consider the traits such as laying rate, fertilization rate, hatching rate, and survival rate at the same time, and take into account the growth speed and body color of each family. Therefore, the family selection method can be adopted. Generations use comprehensive indicators to assess, then determine retention and elimination, and select families to form the core group for the next generation of breeding. Since there is no significant difference in the selection of reproductive performance for high quality broilers, similar to that for laying hens and other broilers, this is not repeated here.
3. Rational use of hybridization
In addition to the above characteristics, special attention should be paid to the rational use of hybridization techniques in the breeding of high quality broilers.
At present, local breeders are very popular with the public. In some provinces, native chickens are the main high-quality broilers in the region. They have a great potential for consumption, and their prices are 50%-100% higher than those of Shiqi hybrid chickens. However, because these breeder breeders have low fertility and slow growth, they are not suitable for commodity production. Practice has proved that full use of local chicken species in China as the material, through the matching hybridization, to select the best hybrid combination, the production site for single cross or single cross on the basis of three-way hybridization and two-hybrid, in order to improve production performance, It is an effective measure for scientific research oriented to production and improving the economic benefits of production. For example, in Guangdong Province, native breeders, a few years ago, the number of certain varieties dropped sharply and mixed with different degrees. After many years of scientific research and teaching unit selection, they have achieved remarkable results, and some have reached no color feathers and do not contain recessive white feather genes. At present, these indigenous breeder chickens are widely used for crossbreeding with other chicken breeds, thereby producing imitation soil quality broilers, and the feeding effect and economic efficiency are ideal.