Economic response to increasing genetic potential for reproductive performance
1987; Elsevier BV; Linguagem: Inglês
10.1016/b978-0-408-10134-9.50034-0
Autores Tópico(s)Agricultural Economics and Policy
ResumoGenetic improvement of litter size in sheep has been shown to be possible both as a trait coded by many genes and by increasing the frequency of a major gene. There is, however, much contradiction and uncertainty about the economic response to improvement. A simplified way has been shown to obtain the economic response per unit change of litter size. The approach is based on the profit for different litter types and their change of distribution following the change of the mean. The profit can either be calculated by subtracting costs from monetary values or estimated by subjective assessment if figures are not available. A general assumption of a constant coefficient of variation is discussed to obtain the distribution of litter types if many genes are involved. It is shown how this is modified by the presence of a major gene. As an example, the economic response per unit change of litter size is derived for the Merinoland breed under different production systems and for a wide range of average litter size. It is shown how the economic response degresses rapidly with increasing mean in the population.
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