Ractopamine in diets for finishing gilts

Abstract

An experiment was carried out using 468 gilts, with an initial weight of 84.77 ± 7.20 kg and allotted into 36 pens to evaluate the effect of the addition of ractopamine in the diets on performance, characteristics and yields of carcass comercial cuts, composition and retail cuts of ham. It was used a randomized block design with four levels of ractopamine (0, 5, 10 and 15 mg/kg of diet) and nine replicates with 13 animals per experimental unit. The initial body weight of the animals was the criterion used to form the blocks. It was not observed any effects of levels of ractopamine on daily weight gain of the animals. Daily feed intake presented a linear reduction when the level of dietary ractopamine was increased. Feed conversion of the animals was linearly improved with the inclusion of ractopamine in the diet. Significant differences were verified at fat and meat proportions on the carcass and wholesale cuts. There was a decreasing linear effect caused by ractopamine on the quantity and depth of fat and a linear increasing effect on lean percentage, on ham meat and on the weights of semimembranosus and gluteus medius. Diets for finishing gilts should contain 15 mg/kg of ractopamine per kg.