Document Type : Research Paper
Authors
Abstract
In this study, production, reproduction, population, management and economic parameters resulted from recording of 12 industrial dairy farms with herd size 20 to 250 and a total of 1240 head of Holstein cows in a cycle of reproduction, during 2010 to 2012 were used to determine the economic values of important traits. The traits of economic importance that appeared in profit equation were durability traits (including survival rate in cow, calf to 3 months of age and heifer from 3 mo to parturition; cow and heifer weight and longevity of cow), health and reproduction traits (including conception rate, live birth rate, calving interval, calving difficulty rate, and age at first calving) and production traits (including calf weaning weight, weight of male fatten calf, milk, fat and protein yield). The economic values and the relative emphasis of traits estimated using maximizing profit by increasing one genetic standard deviation of each trait. The results showed that the sum of relative emphasis of different group of traits for different milk production levels were 38.15 to 36.05 percent for durability traits, 34.80 to 36.59 percent for reproduction and health traits and 27.05 to 27.80 percent for production traits, respectively. The relative emphasis of durability traits and reproduction and health traits decreasing and increasing respectively, with increasing milk production. The estimated relative emphasis of different traits, could be used to construct multiple trait selection indices in dairy cattle breeding programs.
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