Mankind has been using selection since the very moment when the first animal was domesticated. Successfully applying hereditary variability, a man selected and created all breeds of domestic animals and birds. Selection selection is based on the selection of producer pairs in conditions of optimal content and balanced nutrition. Nevertheless, animals belonging to the same species and even one breed, perceive these conditions of content quite differently. Thanks to this, the existing diversity of domestic animals has arisen.
When selecting pigs, there are certain characteristics associated with the biological characteristics of this species. Some of these features greatly facilitate the selection work. One of such qualities inherent in pigs is the high fecundity of this species. In addition, the pigs grow quite quickly and reach puberty, so the generation change takes place extremely quickly. Moreover, while conducting breeding work with pigs, there is an excellent opportunity to observe the results of breeding, since two or three generations of animals can be present in one herd at once.
The second positive feature is the ability to conduct a significant number of crossings within the breed, as well as between different breeds, which gives a sufficiently wide field for the development and improvement of breeding. Another important factor characteristic of pigs is a strong manifestation of variability in the litter itself. So individuals of the same litter differ quite strongly from one another not only in terms of the exteriors, but also in terms of their productive characteristics.
While conducting work on the selection of pigs, it is necessary to take into account the fact that it is practically impossible to foresee the productivity of an individual animal. For this reason, a group of animals-the population-is used for selective work. Only with this approach, it is possible to more or less correctly assess the productivity of the future breed. Thus, a new breed of pigs is created not on the basis of individual individuals, but on the basis of a certain line of animals (population) based on related groups of the herd. In the population there are animals corresponding to the given characteristics, they become the basis of a new breed. However, the gene pool of these individuals is not preserved, but rather enriched with new, useful from the point of view of a person, qualities.
Recently, the use of so-called correlations has been applied in the world and national breeding practice. Under the concept of correlation, the compatibility of traits in the general ontogeny of animals is considered. Since the development of each animal (individual ontogeny) is a complex phenomenon, one can not consider any kind of productive qualities without taking into account other properties of the organism.
In addition to genetic correlation, there is also a connection between physiological and anatomical features. These manifestations can be direct, positive, inverse and negative. Proceeding from this, it is impossible to conduct selection work on any of the features of interest in isolation from other types of productivity. Breeders simply have to use all the relationships to improve the useful qualities, of course, giving special attention to the main underlying characteristics of the breed’s productivity.
One of the new directions in the selection of breeds of pigs is the use of the phenomenon of heterosis, increasing productivity in the case of a special selection based on the genetic characteristics of the parents. Today, heterosis is used both in pedigree and in purely custom pig production.
Basic aspects of breeding in pigs