The selection intensity reflects the proportion
of animals that are needed as parents for the next
generation. Reproductive capacity and techniques
have an important influence on the number of
parents that are needed for the production of
the next generation, and thereby on the rate of
genetic improvement. In poultry, high reproductive
capacity means that about 2 and 10 percent of
the male and female candidates, respectively, are
retained as parents. In cattle, the introduction
of AI has resulted in an enormous reduction in
the number of sires. In dairy and beef cattle, the
bulls used for AI and the cows with high genetic
merit are the nucleus animals, and form less than
1 percent of the entire population.
The selection intensity reflects the proportionof animals that are needed as parents for the nextgeneration. Reproductive capacity and techniqueshave an important influence on the number ofparents that are needed for the production ofthe next generation, and thereby on the rate ofgenetic improvement. In poultry, high reproductivecapacity means that about 2 and 10 percent ofthe male and female candidates, respectively, areretained as parents. In cattle, the introductionof AI has resulted in an enormous reduction inthe number of sires. In dairy and beef cattle, thebulls used for AI and the cows with high geneticmerit are the nucleus animals, and form less than1 percent of the entire population.
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