Estimation of economic values for important traits of Zandi breed based on rural sheep production system by the bio-economic model

To assess the economics of rural sheep production systems and estimation of economic values of important traits in Zandi breed, bio-economic approach was used. In order to estimate economical parameters for using in bio-economical equations and to calculate the EVs of traits, two farms with the flock sizes of 500 and 450 head of Zandi sheep breed in Varamin were studied since the beginning of September 2010 to September 2011. EVs (economic values) of six important traits including pregnancy rate (FE), litter size (LS), lamb weights at birth (BW0), 3 (weaning; BW3), 6 (BW6) months old and survival rate until the age of 6 months (SRL6) were estimated. To estimate the EV of each trait, the level of the trait was increased by both 1% of its mean value and 1 unit while all other traits were constant in their mean values and the amount of change in the profit of system was considered as the EV of the trait. The sensitivity of the EVs was investigated by changing prices of feed and live weight of animals by ±20%. The economic analysis results indicated that the average of feeding cost ratio to the overall costs; and also the average of management cost ratio to the overall costs of rural sheep production system were 64.5 and 33.2 percent respectively and the average annual profit of each breeding ewe in rural sheep production system was 1109594 Rials. The most important trait in this system was FE, followed by LS, BW6, SRL6, BW3 and BW0, respectively when used by 1% increase.