M2508

Educational Tips for Farmers: Polioencephalomalacia (Polio) in Small Ruminants

Causes of Polioencephalomalacia (PEM)

Polioencephalomalacia (also called polio or PEM) is a non-infectious nutritional disease caused by a malfunction of the rumen, which causes thiamine deficiency. Thiamine, or vitamin B1, helps to keep the nervous system healthy. Animals with thiamine deficiency experience neurological symptoms.

PEM is common in young ruminants (kids and lambs) as they transition from milk to solid diets, especially those fed a high-grain diet.

Elevated dietary sources of sulfur can also cause polio, as can overdose of amprolium (Corid), a coccidiosis treatment.

Signs

Partial or complete blindness
Dilated pupils
Loss of body control
Inability to stand
Seizures
Head as far back as possible

A white goat with its head back so far that it is looking toward the sky. An inset graphic shows the brain of an infected animal with abnormalities circled.

A white sheep with its head back so far that it is looking toward the sky. — Animals experiencing polioencephalomalacia often hold their heads as far back as possible, in a position known as “stargazing.”
Images generated by Microsoft Copilot.

Diagnosis

Physical symptoms
At necropsy, flattening of the gyri of the brain and coning of the cerebellum may be present.

Prevention and Control

Provide adequate dietary fiber.
- A general rule of thumb is that sheep and goats should consume 2–4% of their body weight on a dry matter basis.
- Sheep and goats can be fed 0.5 pounds of roughage per 100 pounds of body weight.
Use the proper dosage for amprolium treatments.
Make dietary changes gradually.
Avoid water high in sulfur and excess feeds high in sulfur, such as corn, molasses, and sugar beet byproducts.

Treatment Plan

Most importantly, work with your veterinarian on treatment plans!
Injectable thiamine. To correct a thiamine deficiency, thiamine must be administered multiple times a day over several days. One dose or one dose a day will not correct the problem.
Intravenous products and anti-inflammatories as prescribed by your veterinarian.

The information given here is for educational purposes only. References to commercial products, trade names, or suppliers are made with the understanding that no endorsement is implied and that no discrimination against other products or suppliers is intended.

M2508 (POD-04-26)

By Allison Miner, Bachelor of Science Graduate; Lindsey Dearborn, Master of Science Graduate; Leyla Rios, PhD, Assistant Professor, Animal and Dairy Sciences; and Michael Pesato, DVM, Four State Veterinary Services.

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