عنوان مقاله [English]
The main purpose of this study is to estimate the relative emphasis on production and reproductive traits of growth and longevity in dairy herds of Pars Animal Husbandry Company. This study was conducted using a bioeconomic model and by determining the economic value and relative importance of each of these traits in the breeding programs of dairy cattle breeding system of Pars Livestock Company in Ardabil province. The first step in the development of breeding goals is to determine the economic coefficients for the traits that are considered as breeding goals. The economic value of a trait indicates the contribution of the genetic growth of a trait in improving the economic efficiency of the production system. In order to study the effects of change in input values on the model response, sensitivity test was used. Also, for comparing different attributes, the relative emphasis of each attribute was calculated. The annual profit of each productive cattle in this research was reported to be 5529076.86 9 Rials. Attributes can be divided into several categories in terms of the type of effects on revenues and expenses. A group of traits increase the income and cost of the production unit as well as the profit compared to the baseline (initial amount) by increasing their average. Most of the production traits including milk production, fat production, weight gain after weaning, adult body weight, and survival rate before and after weaning were in this category. However, with an increase of one unit in daily weight gain before weaning, income and expenses have increased compared to the base amount, but the profit has decreased. In the other category were traits whose average increase was both a decrease in income and a decrease in costs, which led to a decrease in profit, which included the traits of production life and the calving interval in this group. The traits of the third group had no effect on income, but as the average increased, the unit costs of production increased, resulting in a decrease in annual profits, which included age at first calving. The fourth category also includes an attribute that has no effect on cost and with the increase of unit income has caused profitability, which is the attribute of milk fat in this category. The results also showed that the highest relative importance or emphasis was related to milk production with a value of 45.01% and the lowest was related to the calving interval of 4.17%.However, in terms of the relative importance of traits in each category, in the group of production traits, milk production and milk fat had the highest relative importance. In the group of survival and survival traits, the priority of survival rate after weaning, survival rate before weaning and production life, as well as in the reproductive group, age at first calving and calving interval were the highest relative importance, respectively. In the group of growth traits, adult body weight, weight gain after weaning and weight gain before weaning, respectively, had the highest relative importance. Sensitivity test results also showed that the effect of fluctuations of production factors on economic values of traits are not the same. and some traits are more stable.