Supplementation, stocking rates, and economic performance of lamb production systems in the Mediterranean-type region of Chile

A simulation model was developed and validated to analyze the bioeconomic performance of alternative technologies applied to lamb production systems in the Mediterranean-type rangelands of Central Chile. The model includes consideration of climatic events that affect pasture growth, the nutritive value of the forage on offer, and animal performance as affected by energy and protein intake of directly grazed native pastures and supplements. Model outputs were compared to experimental results and showed excellent agreement in terms of pasture and animal growth. The model was then used to study the bioeconomic consequences of alternative technologies that could improve animal outputs among large commercial-type operations and also in small farms. It was shown that under current price scenarios for inputs and outputs, the only feasible improvement over extant systems was supplementation with modest levels of concentrates, particularly in small farms, and the simulations showed how costs and benefits are modified by lamb prices. A heuristic methodology was developed to search for local economic optima in terms of minimum costs and maximum net income that appears to apply to existing systems better than linear optimization. © 2005 Elsevier B.V. All rights reserved.