Why are replacement drugs often necessary for animal health?

Replacement drugs are often necessary for animal health because they are specifically designed to compensate for hormonal deficiencies that occur within the body. In certain conditions, an animal may have lower levels of essential hormones due to various reasons such as endocrine disorders or gland dysfunction. For instance, conditions like hypothyroidism or adrenal insufficiency require the administration of replacement hormones to restore normal physiological function.

These drugs help to regulate physiological processes that the deficient hormones would normally control, ensuring that the animal’s metabolism, growth, and overall health are maintained. The use of such replacement therapies is critical in managing chronic conditions and ensuring a better quality of life for affected animals.

The other options do not align with the primary purpose of replacement drugs: boosting energy levels, treating infections indiscriminately, or enhancing muscle growth are different therapeutic targets and do not specifically address the need to replace deficient hormones.