Abstract :
A deterministic bio-economic model was used to estimate the economic values of different
traits in Arabic sheep native to the Khuzestan province of Iran. In the studied system, variable
costs accounted for about 98.5% of the total costs and among variable costs, feed costs
had the highest proportion with 70.7%. Revenue sources included meat, wool, and manure,
where meat was the most important one and formed 95.5% of total revenues. Economic
value for a trait was estimated as the amount of change in the profit of system as its mean
increased by one unit, while the means of other traits were constant. The most important
trait in this system was litter size, followed by ewe survival, dressing percentage, and wool
weight, respectively. Birth weight had a negative economic value but weight at older ages
especially weaning weight and 12-month weight had positive economic values. The sensitivity
of economic values of traits was investigated by changing feed and non-feed costs,
meat and wool prices by ±10%. Results showed that economic values for dressing percentage
and wool weight are not sensitive to change in costs. In addition, changes in marketing
and management costs had no effect on the economic value for traits related to bodyweight
in different ages. In general, the economic value for traits which showed sensitivity to the
changes of costs, except ewe survival, decreased due to an increase in costs. The economic
value for all traits, except birth andwoolweight, changed because of a change in meat price.
Increasing meat price meant a higher economic importance. Among different factors, meat
price fluctuations had the most effect on the economic value of traits.
