Mild to moderate hypokalemia is a very common metabolic disturbance in cattle and is commonly encountered secondary to anorexia as well as a plethora of diseases.
Fundamentally, any condition that causes a bovine patient to go off feed will likely result in mild hypokalemia, explains Simon Peek, BVSc, MRCVS, PhD, Dipl. ACVIM, University of Wisconsin-Madison.
The clinical signs that are seen with mild hypokalemia will pertain to the primary condition, not the hypokalemia itself. However, if severe hypokalemia occurs then the animal will start to show more specific signs related to the hypokalemia. Peek says these will begin with muscle fasciculations, often seen over the triceps and caudal thighs, and increasing difficulty rising from recumbency which may progress to profound weakness and a complete inability to get up or even support the weight of the head or body.
”In fact, severely hypokalemic cattle often show such profound weakness/flaccidity that they resemble botulism cases," Peek notes.
A normal reference range for blood potassium in cattle is 3.6 – 5.4 mEq/L, with mild hypokalemia this will fall into the 2.5–3.5 mEq/L range but will need to drop to 2.2 or below before an animal will exhibit a sustained recumbency.
“Most producers will observe that cattle with severe hypokalemia progress from being apparently able to stand to so weak that they cannot rise within 24 hours, so it is an acute condition to the naked eye, in reality the early signs are so non-specific that there is likely more chronicity to the development of the condition than is easily appreciated,” Peek says.
Read the full article "Managing Hypokalemia" in the January 2012 issue of Bovine Veterinarian here.