A Novel GnRH-Based Immunocastration Vaccine Modulates Growth, Reproductive and Meat Quality Traits in Male Leizhou Goats

Castration is widely used in goat production to improve meat quality and manage reproduction, yet conventional surgical methods raise significant animal welfare concerns. Immunocastration targeting gonadotropin-releasing hormone (GnRH) offers a promising, welfare-friendly alternative, but its efficacy in slow-growing indigenous breeds remains poorly defined. In this study, we developed a novel tandem-repeat GnRH(30) recombinant vaccine and evaluated its effects on growth performance, reproductive function, and meat quality in male Leizhou goats. Eighteen six-month-old bucks were assigned to an immunocastration group (IM), surgical castration group (SC), or intact control group (IC). Vaccinated goats produced sustained anti-GnRH antibodies and exhibited significantly suppressed testosterone levels comparable to surgical castrates. Immunocastration induced marked testicular atrophy, disrupted spermatogenesis, reduced semen volume and sperm motility, and increased sperm abnormalities. Importantly, early growth performance and final body weight were not significantly affected. Compared with intact males, both IM and SC goats showed improved meat quality traits, including reduced drip loss and shear force, accompanied by increased intermuscular fat deposition, with overall patterns in the IM group closely resembling those of surgical castration. Overall, these findings indicate that the GnRH(30) vaccine can effectively suppress spermatogenesis and improve meat quality without affecting growth, providing an effective technical approach for castration management in indigenous goats.