Final answer:
Adult bovine vaccines can be administered via intramuscular, subcutaneous, and intranasal routes to elicit the desired immune response based on the type of vaccine and practicality of administration.
Step-by-step explanation:
The three routes by which adult bovine vaccines can be administered are: intramuscular, subcutaneous, and intranasal. The selection of the route depends on the specific vaccine and the recommendation of the manufacturer or a veterinarian. Each route has its own advantages and is chosen based on the type of immune response desired, the species of the animal, and practical considerations such as ease of administration.
For instance, intramuscular injections are commonly used for vaccines that aim to induce a strong systemic immune response. Subcutaneous injections are chosen for some vaccines to avoid muscle tissue and potential meat damage. The intranasal route can be used for vaccines that target pathogens entering through the respiratory tract and can elicit both mucosal and systemic immunity.