Cow-Calf Certification Practice Exam

What is a key consequence of increased cortisol levels in stressed cattle?

1. Improved reproductive health

2. Enhanced immune function

3. Decreased immune response

4. Higher activity levels

The correct answer is: Decreased immune response

Increased cortisol levels in stressed cattle are primarily associated with a decreased immune response. Cortisol, a hormone released during stress, has several physiological effects, one of the most significant being its immunosuppressive action. Under stress, elevated cortisol can inhibit the function of various immune cells, such as lymphocytes and macrophages, which are essential for mounting an effective immune response. This suppression leaves cattle more susceptible to infections and diseases, highlighting the importance of managing stress in livestock for their overall health and productivity. The other choices do not align with the known effects of cortisol. For instance, while improved reproductive health and enhanced immune function would be beneficial, they are not typically outcomes associated with increased cortisol. Instead, stress and elevated cortisol levels can negatively impact reproductive functions, leading to irregular estrous cycles and fertility issues. Similarly, higher activity levels may occur in some contexts, but generally, stress results in a more subdued behavior as animals conserve energy and avoid potential threats.