Efficiency of the anti-GnRH vaccine for castration of lambs intended for finishing in pastures

Abstract

It was aimed to evaluate anti-GnRH vaccine efficiency on productive characteristics, seminal performance, size, and histology of testicles of lambs submitted to immunocastration. Twenty contemporary Texel lambs were evaluated, being 10 animals received two doses of 1 mL of anti-GnRH vaccine and 10 received two doses of 1 mL of saline, with an interval of 30 days. Seminal characteristics, weight and histological cut for the testicles, productive performance, and blood parameters were analyzed. Andrological monitoring was carried out every 30 days. All animals were kept on pasture of Urochloa spp. receiving daily supplementation protein-energetic by 90 days. There was effect of immunocastration on slaughter weight (44.3 vs. 48.3 kg), total gain (9.9 vs. 10.3 kg), daily gain (104.5 vs. 108.9 g/day), and feed conversion (5.83 vs. 5.97) respectively to immunocastrated and intact lambs. There was immunocastration effect on testicle weight (0.09 vs. 0.35 g), motility (4.5 vs. 61.0%), vigor (0.40 vs. 3.00), volume (0.09 vs. 0.74 mL) and swirling (0.20 vs. 2.70) in the third semen collection. Immunocastration through two doses of 1 mL of anti-GnRH vaccine with a 30-day interval between doses, causes infertility in sheep and can be adopted for lambs.