How does stress affect white blood cell counts in animals?

Stress can lead to pseudo-leukocytosis, which is a temporary increase in white blood cell counts. This phenomenon occurs because, during periods of stress, the body releases stress hormones like cortisol and adrenaline. These hormones trigger the release of white blood cells from the bone marrow and cause them to mobilize from the margins of the blood vessels into the bloodstream, resulting in a higher white blood cell count.

However, this increase in white blood cells is not due to an actual increase in production or a permanent change; rather, it is a physiological response to stress. As the stress subsides, the white blood cell counts typically return to normal levels. This temporary spike can mislead clinicians into thinking there is an underlying infection or another pathology when, in fact, it is simply a response to stress.