In many species used by mankind, breeding programs have a simple structure: e.g. dogs, horses and meat producing sheep and goats. In such programs an intense selection of males takes place, because you only need a limited number of males to produce the next generation. In contrast, only mild selection is practiced in the females, because you need a lot of them as dams to produce the next generation. Thus, selection in females hardly effects genetic progress in the population. In these species the breeding animals (especially the females) are in the hands of individual owners who take their own decisions in which female will be use for breeding and which not. As a consequence, breeding goals change too often and are not used steadilyconsequently, recording of traits and pedigree is less complete, and selection and mating can hardly be influenced. This results in a low genetic improvement rate over generations.
In these species herdbooks play a prominent role in the breeding program. They do the pedigree recording and set the rules for the characteristics of the males and females to be selected as parents for the next generation. The rules for the males are often very strict and only a limited number is approved for breeding. Often a lot of emphasis in this approval is given to conformation. For the females the rules are very loose, disapproval of females is females is seldom practisedpracticed.
In horse breeding a lot is done nowadays to professionalize the breeding program. A limited number of stallions in the breed is approved for breeding by the studbooks and females with the best conformation, health and performance traits are promoted for breeding. This results indeed in a genetic improvement that can be established in analyses.
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In the breeding of dogs, shows play an important role in the selection of males. A limited number of males with the best conformation score at shows is used for breeding, often without any control by the breed association. Nowadays, dog breeding is under discussion in the society due to the negative side effects of a strong selection for extreme conformation and the high relationship among animals in the population leading to inbreeding and the high frequency of genetic defects.
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