برآورد ارزش اقتصادی برای تداوم شیردهی در گاوهای شیری هلشتاین ایران

Background: relative importance of traits is required in multiple traits selection index. objectives: this study was conducted to propose a model to estimate economic value for milk persistency in holstein dairy cattle of iran. methods: production data recorded by animal breeding center of iran were used whereas the required functional and economic data were gathered on 3 large dairy farms. final dataset included a total of 18, 2521 records of first parity cows calved from 2003 to 2011 on 2, 581 farms. the estimated parameters of wood function were used to calculate milk persistency. annual profit was regressed on milk persistency to estimate an economic value for the trait using a multi-covariance analysis. all analyses were performed using different procedures of sas 9.1 software. results: in term of economic conditions of 2011 as a base-year, discounted revenues, costs and profit were us $ 4098.82, 2317.73 and 1781.09 per cow per year on average, respectively. the economic value per kg of milk persistency was estimated to be us$0.043. conclusions: the findings of the research can be useful to define breeding strategies for holstein dairy cattle of iran