Yeast culture in the diet of feedlot steers: performance, carcass traits and feeding behavior

ABSTRACT This study aimed to evaluate the performance, apparent digestibility of diet, ingestive behavior which occurred in two moments, carcass traits, being evaluated constituent and non-carcass components, and also the effect the yeast culture could promote in the peripheral temperature of rumen, hull and body temperature. The diets consisted of a constant ratio of 50% forage (maize silage) and 50% concentrate. Thirty-six steers, ½ Angus Nelore, with average age of 11 months and average initial body weight of 339.5±10kg were used in the experiment. The inclusion of yeast culture promoted a higher daily dry matter intake (8.83 vs 9.35kg day-1) and, consequently, a better daily weight gain (1,143 vs. 1,325kg day-1) in the initial feedlot phase, with no difference in other periods. The apparent digestibility of the diet containing yeast culture was higher than the control diet (69.69 versus 68.32%, respectively), and its use did not interfere with the feeding behavior of the animals. Based on our findings, supplementation with yeast culture may bring positive results in the initial feedlot phase.摘要 本研究旨在评估肉牛的生产性能、日粮表观消化率、分两个阶段记录的采食行为、胴体性状（涵盖胴体组成成分与非组成成分），同时探究酵母培养物（yeast culture）对瘤胃、被毛及机体外周温度的影响。试验日粮均采用50%粗饲料（玉米青贮）与50%精补料的固定配比。本试验选用36头11月龄左右、初始平均体重为339.5±10kg的1/2安格斯-内罗尔杂交阉牛。添加酵母培养物可提升育肥初期的日干物质采食量（8.83 vs 9.35kg·d⁻¹），进而改善日增重（1.143 vs 1.325 kg·d⁻¹），其余阶段无显著差异。添加酵母培养物的试验组日粮表观消化率显著高于对照组（分别为69.69%与68.32%），且该添加剂的使用不会对动物的采食行为造成干扰。综上，育肥初期添加酵母培养物可取得积极的饲喂效果。