Immunocastration and its effects on carcass and meat traits of male pigs

To compose the experiment, 160 male Topgen pigs - 80 surgically castrated (treatment 1) and 80 immunocastrated (treatment 2) - were randomly selected from a commercial swine farm at the moment of slaughter. Surgical castration was performed when the animals were seven days of age and immunocastration was performed by administering two doses (2 mL each) of immunocastration vaccine (analogue of GnRF linked to a carrier protein, development of anti-GnRF antibodies, 200 mg of a GnRF-protein conjugate/mL) when they were 104 and 132 days of age. Animals from both treatments were maintained in masonry stalls, where they received water and ad libitum diet (the same feed for both groups). The animals were slaughtered at 160 days of age, and the length and width of the testicles of immunocastrated animals were evaluated, along with the degree and number of carcass lesions, carcass traits and meat quality of both treatments. The means of these measurements were calculated and compared by Student´s t-test. For the immunocastrated treatment, Pearson´s correlation coefficients were also calculated for testicle length and width with backfat thickness. Approximately 80% of the immunocastrated animals had testicle widths of 11 cm or less. Immunocastrated animals showed higher degrees of lesions, pH (initial and 8 hours), hue, muscle depth and loin eye area and lower brightness, redness, chroma and backfat thickness than the surgically castrated animals. The correlation between testicle length and width with backfat thickness was inverse. Immunocastration can be an alternative to improve the proportion of lean meat (longissimus thoracis) instead of fat (backfat thickness) leading to better carcass and meat quality, since fat has become undesirable from a nutritional point of view in swine.