برآورد ارزش های اقتصادی برخی صفات تولیدی و تولید مثلی در گله گاوهای شیری شمال غرب کشور در شرایط نا بهینه و بهینه سیستم تولید

The objective of this study was to estimate the economic value of productive and reproductive traits in holstein dairy cattle in the north west, based on data collected from eight large herds of three provinces (ardabil, east azerbaijan and west azerbaijan) under sub-optimal and optimal manufacturing system based on market conditions in 2011, was based. in this study, economic values for some production and reproductive traits including milk, milk fat, birth weight, mature cow weight, age at first calving and calving interval, were calculated using a deterministic bio-economic model according and the weighted average revenues and costs of different age groups. economic value of each trait was estimated as the amount of change in the annual profit of production system resulted by one unit increase in the mean of the trait while the means of other traits were hold constant. economic values for these traits were 7297.86, 85301.68, -126286.29, -11785.38, -80752.14 and -197416.81 rials, respectively. production systems for the culling and replacement policies were assumed as optimal herd. then calculation of the economic value of a trait by one unit increase of mean of the trait of the change of the system was re-optimized. system’s profit in optimal condition before and after the change was calculated from the difference between the obtained economic values. economic values for some production and reproductive traits including milk, milk fat, birth weight, mature cow weight, age at first calving and calving interval, were 20833.51,147887.78,-53606.09,-5002.665,-34277.73,-6450.21 rials, respectively. sub-optimized production systems to estimate the economic value of the biased is therefore better estimate the economic values of the optimized systems.