What does "immunization" refer to in veterinary medicine?

Immunization in veterinary medicine refers specifically to the procedure that prepares an animal's immune system to recognize and fight off infectious diseases. Through immunization, animals receive vaccines that contain antigens derived from pathogens, enabling their immune systems to develop protective antibodies. This proactive approach helps to prevent diseases before they can occur, providing crucial protection for animal health.

The other concepts mentioned, such as treating an existing infection, diagnosing diseases, and training for behavioral responses, are distinct from immunization and focus on different aspects of veterinary care. Treating an existing infection involves medical intervention after the disease has already developed, diagnosing diseases requires specialized knowledge and techniques to identify health issues, and training pertains to behavioral conditioning rather than immune responses. Thus, the definition of immunization in this context is accurately captured by the first choice.