برآورد ارزش اقتصادي براي صفات توليدي و طول عمر در گاوهاي هلشتاين

An Evaluation of Economic Values of Milk Production Traits, and Longevity in Holstein Dairy Cattle

A simple model was employed to describe Holstein dairy cattle industry under Iranian production system. Economic values (EVs) for production traits (milk, fat and protein yields) as well as longevity were estimated at farm level for maximized profit perspective and for five types of restriction systems (fixed number of dairy cows, fixed total input including forage and concentrate, fixed amount of milk, fat, and protein yields). The effects of either 20 pcrcent increase or decrease in income from milk sales, feed and non-feed costs were taken as an estimate of model sensitivity. The average absolute EVs on profit perspective and herd size restriction for milk, fat, and protein yields (based on Rials/kg) as well as longevity(Rials/Month) were 983.3, 8021.9, -2086.5 and 55841.5, respectively. Sensitivity analysis showed that the influence of flactuations in milk price on EVs was the highest meaning that its influence on fat and protein EVs was highly considerable. EVs for milk, and fat production show the least and the most sensitivity to price changes (milk, feed and non-feed) respectively.