Economic values for traits of indigenous sheep managed under a low-input production system in north-western highlands of Ethiopia: input to design of breeding programmes

A bioeconomic model based on a deterministic simulation was applied to estimate economic values (EVs) of different traits in indigenous sheep native to the north-western highlands of Ethiopia. Data collected on 4318 sheep were used to describe biological parameters of the model, while economic variables were surveyed in the market. In the studied production system, feed accounted for 74% of the total variable costs, while the sale of live sheep contributed to 88% of the total revenue. Profit was calculated as the difference between revenues and costs of the production variables, which were subsequently used to derive EVs. For each trait its EV was estimated after a unit change in its mean value, keeping the other traits unchanged. After a unit genetic change, the EVs (per ewe per year) for weight at weaning, six months of age, in yearlings and mature ewes were USS 1.46, 0.60, -0.04 and -0.24, respectively. Besides, the EVs for the number of lambs weaned per ewe bred, ewe fertility rate, lambing interval, post-weaning and mature ewe survivals were USS 0.59, 037, 0.16, 0.53 and 0.86, in the order given. The analysis of sensitivity of EVs to fluctuations in the price of input and output parameters revealed that the marginal change in profit was more affected in most traits when the price of live weigh t was altered rather than feed cost. Overall, the results of the present study imply that profitability of sheep production in the low-input production system can be enhanced by implementing selection on traits that have high economic importance.