Determination of breeding objective and economic values for Lori_Bakhtiari breed of sheep in the village system

In this study were used production, reproduction, management and economic parameters resulted from recording of 7 flocks with 1133 head of breeding ewe during annual cycle of production in village system. The profit equation were evaluated for two situations: 1) current situation, that there is not any pay for grazing in range, 2) In this situation, assumed for grazing in range pay as same as grazing in pasture of residual crop and hay farm. To calculate the economic value for traits, the level of trait included in profit equation was increased by 0.1 standard deviation, while all other traits were held at their mean value and change in profit was as the absolute economic value for trait. To calculate the relative economic values, the absolute economic value of each trait divided by the absolute economic value of weight of wool. Sensitivity analysis of relative economic values to price levels of inputs and outputs was carried out. In the current situation, live weight or carcass weight accounted for 95.04% of revenue and wool and manure the remaining 4.96% Feeding and management costs (variable costs) represented about 73.97% and 23.68% (97.65%) of total cost respectively. For the current situation, relative economic values were 33.09 for conception rate, 43.27 for litter size, -2.67 for mature ewe live weight, 1.0 for weight of wool, 30.55 and 35.64 for lamb survival at 3 and 6 month of age, 15.71 for 6-month live weight, 10.87 for dressing percentage, -7.57 for proportion of fat-tail to carcass, 0.59 for fat-tail weight and 25.03 for carcass weight without fat-tail at 6 month of age. The relative economic values of considered traits for situation 2 were slightly less than current situation. Litter size and conception rate were the most important traits in a breeding objective for ewe in village system. Lamb survival at 3 and 6 month of age and carcass weight without fat-tail were the most important traits in a breeding objective for lamb in village system. Sensitivity analysis of relative economic values to changes in prices of input and output indicated that change in cost of input (feed and management) by ± 20% changed relative economic values of traits by equal to less than %2.4, while, change in output (carcass weight without fat-tail) by ± 20% changed these values more than %20.