The objective of the present paper is to estimate the economic feasibility of using urea in two food supplements: standard ration and chicken litter. This food supplement is combined with grazing elephant grass to feed sheep of the Santa Inês breed. In this sense, we adjusted a production function using experimental data, to determine the maximum net income, the time horizon of slaughter and the maximum period to confine the animal when the net income is set to zero. 40 sheep, 20 males and 20 female confined were utilized for 70-day period. The experimental design consisted of randomized blocks with five treatments and four replications. The treatments were the following: I - 50% grazing elephant grass hay plus 50% standard ration: II - 60% grazing elephant grass hay plus 40% ration with chicken litter; III - 40% grazing elephant grass plus 60% ration with chicken litter; IV - 60% grazing elephant grass hay plus 40% ration with urea; and V - 40% grazing elephant grass hay plus 60% ration with urea. The dependent variable used in the adjustment was the weight gains in confinement (Y), and the explanatory variables were the time period of 14 days (T) and dummy variable (D) related to animal Sex. The results indicate that the best model was quadratic models. It also demonstrated that the chicken litter in both levels and the urea in the lower level can not be used in the confinement of the Santa Inês sheep. The use of 60% ration with urea decreases food cost and increases weight gain. Therefore, the treatment V can be replaced with chicken litter in sheep feeding. The ideal age of slaughtering sheep was estimated at 65 days.
economic analysis; sheep; urea
