Merck Manual

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Professional Version

Nutritional Disorders of the Peripheral Nerves and Neuromuscular Junction in Animals


William B. Thomas

, DVM, DACVIM-Neurology, Small Animal Neurology, College of Veterinary Medicine, University of Tennessee

Reviewed/Revised May 2021 | Modified Nov 2022

Pantothenic Acid Deficiency in Animals

Pantothenic acid deficiency may develop in animals (particularly pigs) on rations of corn. Clinical signs include pelvic limb ataxia and a “goose-stepping” gait in which the stifle joints remain extended and the hips flex to lift the limbs off the ground. Histopathologic findings consist of degeneration of myelinated fibers in peripheral nerves and chromatolysis and loss of sensory neurons in spinal ganglia.

Riboflavin Deficiency in Chickens (Curled Toe Paralysis)

Riboflavin deficiency Vitamin Deficiencies in Poultry Vitamin deficiencies are most commonly due to inadvertent omission of a complete vitamin premix from the birds’ diet. Multiple signs are therefore seen, although in general, signs of B vitamin... read more (curled toe paralysis) can develop if feed is not formulated properly. Affected chicks show poor growth, diarrhea, and weakness. There is inability to extend the hocks and progressive inward curling of the toes, so that chicks rest and walk on their hocks. Mortality is high by the third week. At necropsy, the peripheral nerves, especially the sciatic nerves, are swollen. Histopathologically, there is hypertrophy of Schwann cells, demyelination, and minimal axonal degeneration. Chickens often recover with riboflavin supplementation unless the curled-toe deformity is longstanding.

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