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

## TL;DR

A new GnRH vaccine in goats reduces testosterone and improves meat quality without affecting growth, offering a pain-free alternative to surgical castration.

## Contribution

A novel tandem-repeat GnRH(30) recombinant vaccine is developed and tested for immunocastration in Leizhou goats.

## Key findings

- The GnRH vaccine suppressed testosterone levels and testicular development similar to surgical castration.
- Meat quality traits like tenderness and water-holding capacity improved in vaccinated goats.
- Early growth performance and final body weight were unaffected by the vaccine.

## Abstract

Castration is commonly used in goat farming to reduce aggressive behavior and improve meat quality, but traditional surgical castration causes pain and raises animal welfare concerns. Immunocastration is a modern alternative that uses vaccination to temporarily block reproductive hormone activity. In this study, we developed a new gonadotropin-releasing hormone (GnRH) vaccine and tested it in male Leizhou goats. The vaccinated goats produced antibodies that reduced testosterone levels and suppressed testicular development and sperm quality and production, similar to surgical castration. Early growth was not affected. Meat quality traits, including tenderness and water-holding capacity, improved and were comparable to surgical castrations. These findings indicate that the GnRH vaccine can effectively replace surgical castration while maintaining growth and meat quality.

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.