FieldDxHypokalemiaClinical signs, differential diagnosis, treatment and prevention in cattle, sheep and horses.
Overview
Low blood potassium, most often from reduced intake combined with ongoing losses. Usually a combination of poor potassium intake (anorexia) and ongoing losses via milk production, diarrhea, or diuretic use, especially in high-producing dairy cattle.
Clinical signs
- Generalized muscle weakness, depression, anorexia, decreased GI and rumen motility.
- Moderately affected cows (serum K+ 2.5–3.5 mEq/L) appear weak and have depressed GI motility.
- Severely affected animals (serum K+ <2.5 mEq/L, and especially <2.0 mEq/L) are recumbent, profoundly weak, flaccid, unable to stand or support the weight of their head (commonly resting their head in their flanks).
- Profound weakness of lateral cervical muscles.
- Cardiac arrhythmias (atrial fibrillation), tachycardia, muscle tremors, coma, and death.
- Necropsy reveals multifocal vacuolar myonecrosis with macrophage infiltration.
Predisposing factors
- Sustained decrease in dry matter intake (inappetence), abomasal stasis or GI obstructions (left displaced abomasum, right displaced abomasum, abomasal volvulus, abomasal impaction).
- Metabolic alkalosis (causes exchange of K+ for H+ in renal tubule).
- Repeated parenteral administration of corticosteroids with strong mineralocorticoid/kaliuretic activity (especially isoflupredone acetate for recurrent ketosis or mastitis).
- Obligatory potassium loss in milk (1.4 g of K+ per liter).
Look-alikes to rule out
Tick Paralysis Parturient Paresis Downer Cow Syndrome Botulism
Treatment
- Oral potassium administration of feed-grade potassium chloride (KCl) is the method of choice.
- Inappetent lactating dairy cattle should receive 120 g of KCl orally twice at a 12-hour interval (total 24-hour dose of 240 g or 0.4 g/kg BW).
- Intravenous route is used only for initial treatment of recumbent animals with severe hypokalemia (<2.5 mEq/L) and rumen atony
- Inappetent horses benefit from 25–50 g/day of oral KCl.
Drugs mentioned: Potassium
Prevention
1. Maintain adequate dry matter intake. 2. Early detection and correction of abomasal displacements. 3. Avoid excessive use of isoflupredone acetate for ketosis (limit to a single dose). 4. Oral KCl is a mandatory component of fluid therapy in inappetent lactating dairy cows.
Source
A Textbook of the Diseases of Cattle, Horses, Sheep, Pigs and Goat by ELSEVIER (Pages 27–36) 59, 63, 64, 74, 76, 77, 81-84; A Textbook of the Diseases of Cattle, Horses, Sheep, Pigs and Goat by ELSEVIER (Pages 632–646) 60, 61, 65-69, 75, 79, 80, 85-89; The Merck Veterinary Manual 11th Edition (Pages 1004–1005) 78, 90-96.
MSD Veterinary Manual — Hypokalemia in Animals (accessed 2026-08-11)
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