Vet's Perspective

Jun 8, 2012
by WLJ

Managing electrolyte imbalances

Electrolyte balance is critical for proper metabolism and body function.

Potassium is a key electrolyte that can become deficient particularly in cattle around calving season and during severe illness or chronic anorexia. Other agents, such as calcium, sodium and chloride, can be controlled through metabolic processes—but potassium levels are kept under a more narrow range within the bloodstream. This means that when a patient is “off feed,” disturbed levels of electrolytes are a likely consequence.

Conditions typically occurring during early lactation periods, such as displaced abomasum, metritis, ketosis and mastitis are common reasons veterinarians see hypokalemic (potassium levels lower than reference intervals) cases. Although cattle may be affected at any age, first-calf heifers are the most commonly affected.

Each particular condition causing hypokalemia may demonstrate characteristic clinical signs. Early indications of a decreased potassium level in the blood are muscle tremors (especially over the hindquarters) and more difficulty when trying to rise from a lying position. Severe hypokalemia may result in such weakness that a cow cannot rise at all without assistance.

Your veterinarian must analyze a blood sample in order to confirm a diagnosis for hypokalemia. Samples should be run in a timely manner in order to prevent false test results. According to veterinary specialists at the University of Wisconsin, Madison, previous cases of hypokalemia are not necessarily more prone to developing a higher risk of recurrence.

Preventative treatment on the farm typically consists of oral drench potassium supplements. Cattle that do not have blood work analyzed routinely and are recurrent ketosis cases or have been off feed for any length of time should likely receive oral supplementation. Your veterinarian can give you an appropriate dosage for each animal’s approximate body weight as well as attain serial blood potassium levels as needed.

Managers need to dose animals appropriately, however, as potassium levels that are changed too rapidly can be detrimental to heart function.

Like most illnesses, earlier treatment results in a better prognosis for cattle. Recumbent animals deteriorate rapidly and chances for recovery can be less than 50 percent. Animals requiring more than 48 hours of intense intravenous treatment have a less than 10 percent chance of recovering.

Forage and grain feeds should be assessed for adequate nutrient content as well. Work with your veterinarian and local extension agent to help devise a plan that can prevent hypokalemic conditions in your herd. — Dr. Genevieve Grammer

[Dr. Genevieve Grammer is a mixed-species veterinarian practicing in eastern Colorado. Please direct correspondence to drgi].