Castração em bovinos: análise comparativa de métodos, impactos zootécnicos e bem-estar animal

Castration of male cattle is a widely used zootechnical practice aimed at facilitating handling and improving carcass quality. However, it raises important concerns regarding animal welfare. This literature review aimed to analyze and compare the main castration methods in cattle, surgical (open versus closed), physical (elastration and Burdizzo), chemical (intratesticular injection of agents such as calcium chloride or lactic acid/papain), and immunological (anti-GnRH vaccines), with respect to their techniques, zootechnical impacts, and physiological implications. A narrative literature review was conducted based on scientific articles, theses, and dissertations, seeking to evaluate the effects of each method on productive performance (average daily gain – ADG), carcass characteristics (fat cover and marbling), and animal welfare indicators (cortisol levels, haptoglobin, cytokines, behavioral changes, and the occurrence of health complications). The comparative analysis showed that surgical castration, although effective, is associated with intense acute pain, an initial performance “setback,” and risks of postoperative infection. Elastration was associated with chronic pain and prolonged inflammation, resulting in poorer welfare outcomes than those observed with surgical castration. The Burdizzo method showed average daily gain similar to surgical castration but with a potentially more intense inflammatory response. Chemical castration presented inconsistent results, with some agents, such as calcium chloride, associated with severe adverse reactions, whereas others, such as lactic acid and papain, showed promising outcomes. Immunocastration emerged as the most balanced alternative in terms of animal welfare and productive performance potential, as it eliminates acute pain associated with conventional methods and allows the exploitation of anabolic growth; however, it requires specific management, such as multiple doses or the use of implants. In addition, the use of multimodal analgesia, combining nonsteroidal anti-inflammatory drugs (NSAIDs) and local anesthetics, proved effective in mitigating pain and improving productive performance when associated with traditional methods. It is concluded that there is no universally ideal castration method, and the choice depends on the production system, the age of the animals, and the degree of prioritization of animal welfare. A growing trend is observed toward the adoption of immunocastration and the optimization of traditional methods through the systematic use of analgesia.