Comportamento e desempenho de suínos imunocastrados

Abstract

This research was divided into two experiments to evaluate the behavior and performance of immunocastrated males pigs compared to females and surgically castrated males during the periods before and after the full immunization. The experimental experimental period lasted 70 days, during the growing and finishing phases. The animals were distributed in a completely randomized design with three treatments (castrated males, females and immunocastrated males). Experiment1: 30 animals divided into three pens, with ten animals per treatment, and the performance of five animals per pen was evaluated. The experiment was divided into 3 periods: before the 1st dose of vaccine immunocastration (Period 1), between 1st and 2nd dose of vaccine (Period 2) and after the 2nd dose of the vaccine (Period 3). The observations were used for composition histogram, characterizing the proportions of time devoted to each behavior. In a general way, all three categories spent most of their time sleeping. Immunocastrated males had higher proportions of undesirable behaviors in relation to surgically castrated males and females, and these were reduced after the second vaccine dose. Experiment 2: 45 animals were distributed into three pens per treatment with three replicates of five animals. The animals were weighed at the beginning of the experiment and at the moment of the first and second dose of vaccine immunocastration and end of the experiment. Blood samples were taken on the same dates the animal sweighing. Immunocastrated males had lower protein efficiency, reflected by increased plasma urea nitrogen (NUP) only after the second injection of the vaccine (110 days). There were no differences in weight gain between the categories in periods. Immunocastrated males had lower feed intake than females and these, on the other hand, smaller than castrated males. To 110 days of age, the immunocastrated animals showed feed conversion similar to females and better than castrated males. The best utilization of dietary protein resulted in little benefit performance, showing less prominent results in animals with low to medium genetic potential.