Corriedale sheep production when supplemented with ryegrass pasture in southern Peru

Abstract

Simulations of a sheep production system in southern Peru were performed using the Texas A&M Sheep Simulation Model. Evaluated were management options for age at first breeding (ewe lamb versus yearling ewe) and six ryegrass supplementation treatments: no supplementation (BASE); supplementation before and during breeding season (FLUSH); supplementing all sheep or replacements under one year of age in August, September and October (SUP3-ALL and SUP3-REP); supplementation of lambs in April, May, August, September and October (SUP5); supplementation of lambs from April to October (SUP7). Biological and economic evaluations of the results were performed. Generally, supplementation increased reproductive rate, offtake per ewe and sale weight. However, these increases were not always translated into increased biological efficiency or profitability. When ewes were bred as yearlings only the SUP7 treatment was more profitable than the BASE treatment. Profitability of ryegrass supplementation increased when ewe lambs were bred; all treatments except SUP3-REP were more profitable than the yearling BASE treatment, with the SUP7 being the most profitable ($61.40 per 100 head over yearling BASE). If the sheep enterprise absorbed the entire cost of ryegrass production, versus sharing costs with other livestock, only BASE, SUP5 and SUP7 for ewe lambs ranked above the yearling BASE treatment.