Estimation of the economic values for the important traits of Zel Sheep in the intensive production system using a bio-economic model

To estimate economic values (EVs) of seven important traits including pregnancy rate (PR), litter size (LS), lamb weight at birth (BW0), three (weaning; BW3), six (BW6) and nine (BW9) months weight and survival rate until the age of 6 months (SR) in Zel sheep under an intensive production system in Mazandaran province of Iran, data from two farms were analysed using a bio-economic model. Variable costs accounted for about 99% of the total costs and the feed costs had the highest proportion with 72.54%. Among the income sources, the sale of surplus animals formed 81.4% of the total revenues. The EVs were estimated as the amount of change in the profit of the system after each trait mean increased by both 1% and one unit, while all other traits were constant at their mean values. The most important trait in this system was LS, followed by SR, PR, BW9, BW3, BW6 and BW0 respectively. The sensitivity of EVs was investigated by changing prices of feed and live weight of 9-month-old lambs by ±20%. Results showed that the EV of BW9 was the most constant and EV of BW0 was the most variable. As the prices of feed and live weight of 9-month-old lambs were simultaneously changed by ±20%, the variation in the EVs decreased and they showed more consistency. This study showed that the profitability in an intensive production system of Zel sheep could be increased by improving LS, SR, PR and BW9.