At present, there are more than 60 domestic rabbit species. Why should people pay attention to the selection and breeding of varieties in rabbit production? Are ready-made varieties directly used? This issue may not be a problem for rabbit industry experts and professional technicians, but it seems to be clear to most rabbit farmers, but it is difficult to say clearly. The author now combines his professional field and focuses on the selection and breeding of rabbits.
Why do we need to breed and breed rabbits
Selection is what we usually say. In production practice, we select individuals who are relatively good and meet people's needs to be left for breeding, and to eliminate poor or poor individuals from their herds or leave them for further improvement. This method is used in livestock breeding. Learning is called selection. Breeding is based on selection and matching, accelerating the improvement and improvement of existing varieties and measures for breeding new varieties.
The concept of breeds and the basic conditions for their composition
The breed is the concept of animal husbandry. Any breed of livestock is a product of artificial selection. The breed is a group of people with certain morphological characteristics and production performance that has been artificially selected from common ancestors. Livestock breeds generally have the following characteristics or conditions. In the absence of any one of the conditions, they can deny their capital as a breed.
The same source of any rabbit (animal) breed is not a group of disorganized animals, but a biological group with a common source and similar genetic basis.
Similar traits and adaptability Rabbits of the same breed are similar in terms of ancestry, breeding conditions, and breeding methods, and are often similar in appearance, physiology, important economic traits, and adaptability to natural conditions.
Higher economic value Rabbits of the same breed should have a consistent productivity direction and higher productivity levels. If the economic value is low, they will not be cultured by people, and they will lose the value of cultivation.
The hereditary nature of stable genetic properties and high stability of heredity means that body shape appearance, production performance, growth and development, and important economic traits are relatively stable, and their stability is not only reflected in the inter-individual consistency within the breed, but also in the upper and lower generations. Stability. The high seed use value not only indicates that a typical trait of a cultivar can be stably inherited to offspring, but also shows a higher heterosis or a better improvement effect when the cultivar is hybridized with other cultivars.
A certain population structure of 30 ~ 50, 300, 500 can not meet the requirements of a variety, a species generally have more than 3 strains, each strain has a few more families, and strains and families have their own The independent characteristics of the species, that is to say a species must have a number of groups with different characteristics. The existence of different taxa within the breed has resulted in the heterogeneity of the variety. It is precisely because of this heterogeneity or the diversity of the species that it has laid the foundation for breed selection and improvement. The general rabbit species requires 600 to 1500 female rabbits, and promotes the production of more than 20,000 female rabbits, and each breed requires 200 to 300 females.
The genetic basis of selective breeding
From the concept and characteristics of varieties, we can recognize the following issues:
The purity of the species is relative to all rabbit breeds (as are other breeds of livestock) and their purity is relative. From a production point of view, we call a species or strain purebred, but only for some of its major economic traits and major characteristics, rather than the homozygous locus of all genes in its genome, so genetically speaking rabbits The varieties have not yet been completely pure. In animal husbandry, purebreds are individuals or groups that can confirm that their parents belong to the same breed. A hybrid that has progressed more than four generations through progressive hybridization can be regarded as a pure race as long as its characteristic characteristics are basically the same as its improved variety. Actually, the term “pure breeding†does not have a strict genetic meaning. It's just the customary language used in livestock breeding. The existing purebred animals only appear in experimental animals, such as purely Kunming mice, and the emergence of this pure line of mice is achieved through inbreeding and continuous inbreeding for more than 20 generations. The inbreeding coefficient and the kinship coefficient of the time population were over 98.6% and 99.6%, respectively, and the degree of genetic similarity between individuals almost reached the level of identical twins. There are no such individuals in livestock. Since inbreeding can expose harmful genes, leading to declines in individual viability and productivity, inbreeding is rarely used in production, and inbred animals are rarely present in domestic animals. People are very cautious even when using inbreeding during the breeding process. This is mainly due to the fact that it is very difficult for the general production floor home to suffer the loss of production due to the adoption of in-flight. Obviously, all rabbit breeds are genetically heterozygous. It is precisely because of the heterozygosity of varieties or strains that they provide the basis for our selection and breeding. It is also due to the purity of the variety. We have the potential to improve breeding and further development. This is one of the important reasons why we have to select and breed a mature variety.
The purity of the species is affected by the environment. The purity of all livestock breeds or populations is affected by environmental conditions. The genetic structure within the population is often mutated under the influence of internal and external environmental factors. In the practice of breeding, we often see such a situation: when a trait with a uniform character is introduced into another ecological region, the phenomenon of inconsistent traits occurs; the more places where a cultivar is introduced, the more ecology is introduced into the land. The more complex the environment is, the more the flow of the gene of the species is, and the greater the possibility of changes in the direction of production at the place of introduction, the more types of production will result from it. Therefore, after the introduction of a variety, after several years, even if there is no exotic hybrid, the production capacity and production direction of the variety will also change. This is the reason why different regions breed the same variety, and the users have different opinions about the same variety. It can be seen that only one species can maintain its development in the future by continuous seed selection. Only by insisting on breeding can it promote the update of varieties and realize the alternation of old and new varieties. This is how we select and select a mature rabbit breed. Another important reason for childbirth.
The existence of a species is a time limit for the existence of any species of livestock, and the variety is produced by the emergence of → new varieties, which is a natural law. The demise of a breed or a strain is often due to the following reasons: First, the productivity of the breed declines or fails in the competition for the ability to match; Second, the direction and type of the breed change due to environmental changes; Third, the breed has outstanding characteristics Individuals or groups of individuals will develop into new varieties through cultivation and development into another new strain. In order to maintain a variety, people often take many measures, such as expanding the number of species conserved by the group, controlling matching, preventing in-flights, and prolonging the interval between generations, so as to maintain a species as long as possible. However, in fact, it is very difficult to maintain a long-term change of a species, unless a species is in a large population of random mating, and there is no influence of factors such as mutation, selection, migration, and genetic drift, that is, only The group is in a Hardy-Weinberg equilibrium and a breed will remain unchanged for a long period of time. However, this ideal state is very difficult to achieve. Among them, introduction is the most likely and most likely cause of the loss of a variety of genes. Introduction not only leads to genetic drift, but often because of the small number of introductions, it is very easy to cause near in the breeding process. Crossing, leading to gene loss, and the accumulation of long-term mutated genes, it is difficult to ensure the integrity of the genetic structure of the original cultivar after several years of development. This is the third important reason why we have to select and breed a mature rabbit breed.
The necessity of breeding and breeding
Strengthening the selection and breeding of rabbit breeds not only meets the requirements for the intrinsic development of a breed, but also the needs of rabbit production. Our country has a vast territory and there are great differences in natural conditions. There is no single species that can fully adapt to all conditions. Therefore, on the basis of analyzing the necessity and possibility, it is necessary to cultivate varieties that have their own characteristics and can adapt to their own ecological environment. In addition, in order to meet the needs of special production and production of new products, it is also necessary to cultivate some new rabbit breeds or strains. For example, the cultivation of colored rex rabbits and colored long-haired rabbits can meet the special requirements for fur color in the leather production or wool spinning industry, which not only saves the dyeing process, but also reduces the environmental pollution. Cultivating our own new varieties or new product lines is also a solution to the long-term situation in which China has introduced a large number of excellent rabbit species from abroad and is economically dependent on foreign countries. It can turn our resource advantages into product advantages and economic advantages, and enhance China’s rabbit breeding industry. International status.
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