Effect of Energy Level on the Protein Requirement of Lambs Fattened with and without Stilbestrol

Abstract

A 2₃ factorially arranged feeding trial was conducted with 16 groups of 12 fattening lambs each to evaluate the response of lambs fed different amounts of protein and energy with and without stilbestrol. Interactions between digestible protein and ENE fed at 90 and 120% of recommended amounts were detected for liveweight gains, grades and feed efficiencies. The lambs fed the high energy rations apparently required more protein than those fed the low energy rations to maintain feed intake and growth rate. Lambs receiving the high level of protein gained faster, graded higher and were more efficient than those fed the low level. Differences between energy levels were not observed. Actually differences existed between energy levels within each protein level but were in a different direction within each protein level and were detected as a protein by energy interaction. Stilbestrol significantly increased average daily gains (approximately 0.05 lb. per day) and feed efficiency (5.42 vs. 4.49 therms ENE required per lb. gain) but decreased liveweight grade approximately one-third of a grade. No interactions were detected between stilbestrol, protein and energy in liveweight gains or grades. Copyright © . .