TOURINHOS NELORE INTEIROS OU IMUNOCASTRADOS TERMINADOS EM CONFINAMENTO COM DIFERENTES NÍVEIS DE CONCENTRADO

Abstract

The objective of this study was to evaluate the performance, carcass and meat characteristics of intact or immunocastrated Nellore males finished in feedlot with different levels of concentrate. Ninety six males, twenty two month old were randomly distributed in four treatments, in a completely randomized design in a 2x2 factorial scheme, being two sexual conditions, kept intact or castrated, and two levels of concentrate in the diet, 42 or 80%. The confinement period was 84 days, preceded by a period of 21 days of adaptation. The animals of the immunocastrated group received two doses of the Bopriva® vaccine, the first at the beginning of the adaptation and the second dose 21 days later. At the time of initial and final weighing, morphometric measurements were performed on the animals: rump height, body height, rump width, chest width, body length, thoracic perimeter, and, also, body condition score. At the end of the confinement the animals were slaughtered and the data regarding the quantitative and qualitative characteristics of the carcass and meat were collected. Non-castrated animals obtained greater daily weight gain and higher final weight. Non-castrated animals obtained better feed conversion, while the concentrate level did not influence this variable. Immunocastrated animals and animals that consumed high concentrate diets obtained larger gains of croup width. Non-castrated animals obtained greater gain in body condition, had higher warm and cold carcass and forequarter weights. Had also higher cushion thickness and arm perimeter. The animals that consumed high concentrate diets had higher hot and cold carcass yield. Immunocastration improved meat color which is considered important at the time of purchase of meat by the consumer. Immunocastrated animals obtained better performance in weight gain, feed conversion, slaughter carcass weight and yield, cushion thickness, arm circumference. However, the immunocastrated animals presented better meat coloration.