Performance and plasma urea nitrogen of immunocastrated males pigs of medium genetic potential

Objective. A study was carried out to evaluate the performance and the plasma urea nitrogen (PUN) of male pigs of medium genetic potential for lean meat deposition in carcass, which underwent immunocastration. Materials and methods. Forty-five seventy-days old Large White x Landrace crossbred were used. The pigs were distributed in a randomized design in three treatments: castrated males, females and immunocastrated males. Each treatment group was replicated three times with five pigs per replicate. The trial period was of 70 days, divided into phases of growing (70 to 110 days old) and finishing (111 to 140 days old). The pigs were weighed four times: at the beginning of the trial, at the first immunocastration vaccine dose (80 days old), at the second immunocastration vaccine dose (110 days old) and just before slaughter (140 days old). Blood samples were taken on the same day that the animals were weighed. Results. Between 80 and 110 days old, there was an increase in PUN value, only for castrated males and females. No differences were found in weight gain between the studied groups within the periods. Immunocastrated males had lower feed intake than females and these had a lower feed intake than castrated males. To 110 days old, immunocastrated animals showed feed conversion ratio similar to females and better than castrated males. However, after the second dose of the vaccine, feed conversion was similar between groups. Conclusions. The benefits of immunocastration are prominent in animals with low to medium genetic potential.