Nutritional Myopathies in Ruminants and Pigs

Important Concepts

• Nutritional Myodegeneration (NMD): Also known as white muscle disease, caused by selenium or vitamin E deficiency.

• Hypokalemic Myopathy: Severe muscle weakness due to low potassium, often seen in dairy cattle.

Clinical Changes

• NMD: Weakness, stiffness, difficulty rising, respiratory distress, dysphagia, cardiac arrhythmias.

• Hypokalemic Myopathy: Muscle weakness, recumbency, tachycardia, rumen hypomotility, and atony.

Pathological Changes

• NMD: Muscle degeneration, pale discoloration, white streaks in muscle bundles, calcification, and intramuscular edema.

• Hypokalemic Myopathy: Vacuolar myopathy in muscle biopsies.

Diagnosis

• NMD: Low blood selenium and vitamin E levels, increased CK, AST, and LDH.

• Hypokalemic Myopathy: Serum potassium < 2.0 mmol/L, ketosis, metabolic alkalosis.

Treatment and Prevention

• NMD: Injectable selenium and vitamin E, oral supplementation, adequate nutrition, and high-quality forage.

• Hypokalemic Myopathy: Potassium supplementation, addressing primary causes of ketosis, supportive care.

For more detailed information, visit the Merck Veterinary Manual on Nutritional Myopathies.