PRODUCTION ECONOMIC ANALYSIS OF LAMB FEEDING UNDER ALTERNATIVE FORAGE-CONCENTRATE RATIONS (NEW MEXICO)

The study involves the estimation of feed response functions for fed lambs to rations utilizing alternative proportions and amounts of forages and concentrates. The analysis makes use of data from three years of lamb feeding trials in New Mexico. Consistent with the analysis of the results of the experiments by animal scientists, vaccination of lambs or the feeding of antibiotics had no measurable effect on feedlot performance. Consequently, the feeding trial data from all lots were pooled for economic analysis.;With the traditional response analysis approach, the power function provided the best fit for the response surface. Derivations include those of least-cost feed combinations and most profitable levels of gain expressed both on a live-weight and dress meat basis. Because the choice of ration can have an important effect on the length of the feeding period, time-related costs were also included. Introduction of time into the profit equation has a marked effect on the optimal levels of gain.;Conclusions and implications are drawn toward feeders pursuing alternative objectives in the U. S. sheep feeding industry. Other implications are related to land use strategies and sheep production in important sheep-producing developing countries.;While similar analyses have been completed for other livestock types, this is perhaps the first fed response study ever completed for fed lambs. The research included both the direct estimation of gain isoquants and the traditional method of indirectly deriving isoquants from the response function. The direct estimation technique resulted in an isoquant shape similar to that derived for beef which exhibits increasing and decreasing marginal rates of substitution between feeds.