All breeds of sheep and goats are susceptible to white muscle disease and it is most common in new-borns or fast growing animals such as the Boers
Waking up to the sight of your goats unable to move can be disturbing. This is what happened to Abdallah Mwanja, a smallholder farmer hoping to establish a backyard goat rearing business at his home in Kirangira Village, Mukono District.
A Boer goat buck he acquired handsomely could not help itself to stand although it would eat normally.
There were no overt signs of illness, just reluctance to stand. Four days later, it was dead. This was the third death in one week in his flock with initial suspicion of a viral attack.
White muscle disease plague
A veterinarian concluded that instead the flock was sick with white muscle disease, a nutritional myopathy arising from change of diet.
According to Livingstone Kyobe Ssebweyo, the white muscle disease is caused by a deficiency of selenium and/or vitamin E.
It is a progressive muscle disease found in all large animals including cows, sheep and goats.
In humans, selenium deficiency leads to goitre normally mitigated by iodine supplementation.
Small ruminants require energy, protein, vitamins, minerals, fibre, and water. Deficiencies, excesses, and imbalances of vitamins and minerals can limit animal performance and lead to various health problems.
According to Kyobe, although ruminants can be fed different feeds, it is very sensitive to drastic changes in the diet. Mwanja had actually changed the diet for his confined animals from fresh grass to hay.
Kyobe explains that feeding animals on poor quality hay without access to pasture is the major cause.
Cause and symptoms
Although Mwanja feared a viral infection, white muscle disease is not, according to Kyobe.
All breeds of sheep and goats are susceptible to white muscle disease and it is most common in new-borns or fast growing animals like the Boers. Kids are more susceptible than lambs, possibly because they have a higher requirement for selenium. Affected animals may have normal appetites until they become too weak to nurse.
According to Kyobe, there are two forms of white muscle disease; an inbred form that affects the cardiac muscle, and a delayed form that is associated with either cardiac or skeletal muscle. Kyobe says that calves affected by the hereditary form usually die within 2-3 days of birth due to cardiac muscle degeneration.
Animals affected by the delayed form may exhibit signs ranging from general unthrift and stiffness, to walking with an arched back and spending more time resting, depending on the level of selenium in the diet.
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, foamy nasal discharge, and fever.
Feed accounts for the majority of the cost of raising goats; in fact, as high as 70 per cent of total production.
Kyobe says: “Nutrition is the foundation of good health. Animals on a higher plane of nutrition are more resistant to many diseases. Nutrition problems are second only to respiratory problems in frequency of occurrence.”
Sheep and goats require five essential nutrients including water, energy, protein, minerals and vitamins.
Kyobe explains that fresh legumes and pasture are good sources of vitamin E as stored feeds tend to be poor sources of vitamin E. Stored feeds can lose up to 50 per cent of their vitamin E a month, he notes. According to Kyobe, animals affected by white muscle disease can be treated with sodium selenite and vitamin E depending on body weight. “If necessary, the treatment may be repeated two weeks later, but no more than four doses total should be given,” he says. When white muscle disease 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.
Calves and kids can be administered with simple vitamin E deficiency, treatment with dietary supplementation or using substances rich in vitamin E. He recommends oral administration of selenium over injections. Kyobe says the disease can also be prevented by adding selenium to animal feed in areas of known deficiency. Selenium deficiency in Uganda is identified in Kisoro, Bundibugyo, Hoima and Kapchorwa districts.
The recommended supplemental levels can be calculated on the basis of total dry-matter intake by specialists to avoid selenium toxicity.