Growth and carcass characteristics of pasture fed LHRH immunocastrated, castrated and intact Bos indicus bulls.

ABSTRACT

The effectiveness of a luteinizing hormone-releasing hormone (LHRH) fusion protein vaccine or surgical castration, at two years of age, on growth and carcass characteristics of Bos indicus bulls was evaluated. Seventy Nelore-cross bulls were divided into three groups (1) immunized, (2) castrated and (3) intact control. At slaughter (three years of age), intact bulls had higher body weights, ADG, carcass weights, and muscle percentage compared to immunized and surgically castrated animals. Both castrated and immunized animals had greater marbling and percent carcass fat than the intact bulls. Average tenderness scores were inferior for intact bulls compared to immunized and castrated animals, but these differences were not significant (P>0.05). Juiciness, flavor, thawing, nor cooking losses differed significantly among the three groups. Immunocastration was effective in producing carcass traits similar to that of surgical castration. Therefore, immunization with LHRH fusion proteins appears to have practical utility in the management and castration of grazing bulls.