Michael Metzger, Michigan State University Extension Educator
(Previously published on MSU Extension, Sheep & Goat: January 19, 2019)
If you 
are raising sheep and goats in Michigan or other selenium deficient areas, you need to take measures to prevent white muscle disease.
White muscle disease (WMD) is caused by a deficiency of selenium and/or vitamin E. It is a degenerative muscle disease found in all large animals including sheep and goats. Generally, it is not known which. Selenium (Se) deficiency is associated with selenium deficient soils and the inadequate uptake of selenium by forages grown on these soils. Certain areas of the U.S., including Michigan, are considered low in selenium levels. Vitamin E deficiency is independent of soil type and more closely reflects forage quality. Fresh legumes and pasture are good sources of vitamin E and stored feeds tend to be poor sources of vitamin E. Stored feeds can lose up to 50% of their vitamin E a month. All breeds of sheep and goats are susceptible to WMD and it is most common in newborns or fast growing animals. Kids are more susceptible than lambs, possibly because they have a higher requirement for selenium.
The disease can affect both the skeletal and cardiac muscles. Skeletal muscles symptoms vary from mild stiffness to obvious pain upon walking or an inability to stand. Lambs/kids may tremble in pain when held in a standing position. Hunched animals with a stiff gait are common. Affected lambs/kids may remain bright and have normal appetites until they become too weak to nurse. When the problem occurs in newborns, they are born weak and often cannot get on their feet. Sudden exercise may trigger the condition in older lambs and kids. In adult animals deficient animals may have poor conception rates, abortions, stillbirths and miscarriages, retained placentas, or deliver weak kids or lambs. Cardiac symptoms can be very similar to pneumonia. They include difficult breathing, frothy nasal discharge, and fever. Heart rate and respiratory rate are elevated and irregular. Both types of WMD often occur at the same time. When WMD affects the skeletal muscles it can be treated with supplemental selenium and vitamin E and animals should respond within 24 hours. Cardiac muscle damage is often permanent.
White muscle disease can be prevented by supplementing selenium and vitamin E in areas where soils are deficient. Selenium supplementation is controlled by law. Total daily consumption of selenium must not exceed 0.7mg/head/day. Ideally the total diet for sheep and goats should contain between 0.10 to 0.30 ppm of selenium. Injectable forms of selenium are available, but are a poor alternative to supplementing in the feed and Michigan State University Extension does not recommend using an injectable form of supplementation in sheep and goats.