Department of Animal Science, University of Tehran, PO Box 3158711167-4111, Karaj, Iran.
J Dairy Sci. 2012 Jun;95(6):3406-18. doi: 10.3168/jds.2011-4573.
Trait-by-trait and multiple trait bioeconomic modeling were used to derive farm-specific economic weights (EW) for a wide range of traits under different production and economic circumstances to define breeding objectives for Holstein dairy cattle in Iran. Production parameters and economic data were gathered on 10 dairy farms from March 2008 to February 2010. The EW (economic values multiplied by gene expressions, in US dollars per unit of trait per calf born from sires of self-replacing females in planning horizon of 20 yr) were estimated to be $0.15 per kilogram of milk yield; $1.36 per kilogram of fat yield; -$1.02 per kilogram of protein yield; $4.59 per month of longevity; -$1.22 per kilogram of mature cow weight; -$105.67 for combined somatic cell score and clinical mastitis; -$1.35 and -$0.28 for percentage direct and maternal calving difficulties, respectively; -$3.98 for percentage direct stillbirth; -$0.76 per day of age at first calving; -$0.72 per calving interval day; and $0.91 for percentage 56-d nonreturn rate on averages across investigated farms. The coefficient of variation of economic weights across the 10 farms was lowest for direct calving difficulty and highest for calving interval. The proposed Iranian selection index was compared with selection indices of major countries exporting semen to Iran. Average relative emphasis for production, durability, and health and reproduction, across all exporter countries, was 41, 37.5, and 21.5%, respectively, whereas the respective values were 50, 14, and 36% for the Iranian index. Significant differences in selection indices may potentially decrease the utility of importation of semen as a means of achieving sustainable genetic progress in Iran. Results obtained in this study provide important information about economic values of traits that can be used to improve the Iranian national progeny testing program as well as importation rules for semen to Iran.
利用特质逐个性和多特质生物经济模型，针对不同生产和经济环境下的广泛特质，推导出了特定于农场的经济权重（EW），以确定伊朗荷斯坦奶牛的育种目标。从 2008 年 3 月到 2010 年 2 月，在 10 个奶牛场收集了生产参数和经济数据。在规划期为 20 年的自我替换雌性母本的小牛出生时，每单位特质的经济价值（经济价值乘以基因表达，以每头小牛出生时每头奶牛的美元数表示）估计为每公斤牛奶产量$0.15；每公斤脂肪产量$1.36；每公斤蛋白质产量$-1.02；寿命每月$4.59；每头成年奶牛体重$-1.22；体细胞评分和临床乳腺炎合计$105.67；直接和母体难产的百分比分别为$-0.28 和-1.35；直接死产的百分比为$-3.98；初产日龄$0.76；产犊间隔天数$0.72；56 天非发情率百分比为$0.91。在 10 个农场中，经济权重的变异系数最低的是直接产犊困难，最高的是产犊间隔。所提出的伊朗选择指数与向伊朗出口精液的主要国家的选择指数进行了比较。在所有出口国，生产、耐久性和健康与繁殖的平均相对重点分别为 41%、37.5%和 21.5%，而伊朗指数的相应值分别为 50%、14%和 36%。选择指数的显著差异可能会降低进口精液作为实现伊朗可持续遗传进展的一种手段的效用。本研究的结果提供了关于特质经济价值的重要信息，可用于改进伊朗国家后裔测试计划以及向伊朗进口精液的规则。
