Ractopamine in diets with nutritional adjustments for finishing barrows under high ambient temperature

Abstract

Supplementation of diets for finishing barrows with ractopamine can result in improved performance and carcass characteristics. Thus, the objective of the study was to evaluate the constant and gradual increase of ractopamine supplementation in diets with adjustments nutritional for finishing barrows created under high ambient temperature. We used 84 barrows distributed in six treatments (supplementation constant 0, 5, 10 and 20 ppm and gradual increase of 5 to 10 ppm and 10 to 20 ppm ractopamine) with seven replicates of two animals each. The constant supplementation with 10 and 20 ppm and the gradual increases with 5-10 and 10-20 ppm showed higher daily intakes of digestible lysine in relation to the group supplemented with 5 ppm and the control group. The other variables were not affected by treatments. Diets containing ractopamine and adjusted nutritionally not improve the performance of finishing barrows created under high ambient temperature. The constant supplementation of diets with 20 ppm and the gradual increases with 5-10 and 10-20 ppm of ractopamine increase the amount of meat and the carcass bonus rate of barrows created under high ambient temperature.