Have you ever heard of “White Muscle Disease”? If not, it is caused by your livestock rations being deficient in selenium.
Selenium is an important trace element required in livestock rations. A significant research finding reported from Oregon State University in 1958 was that the underlying cause of white muscle disease was a dietary deficiency of the trace element selenium (Se).
The relationship between soil, plant, and animal factors involved is clear-cut. Certain soils, formed within the past 10,000 years or so because of volcanic action, contain practically no selenium.
As a result, plants grown on them are seriously selenium-deficient, and the deficiency is passed onto animals eating them in the form of fresh forage, hay, or silage, as all or most of their diet.
In addition, Clover and alfalfa do not pick up selenium as readily as some other plants. Cattle grazing legume pastures or feeds grown in soils that contains sulfur may develop deficiency.
Fields with high crop yield; intensive irrigation (that leaches selenium out of soil) and fertilization (which stimulates plants to grow faster, with less time to accumulate as much mineral from the soil) may contribute to selenium deficiency in some crops. The illustration below shows Se levels found in the United States.
The following information is from the fact sheet, “White Muscle and Other Selenium-Responsive Diseases of Livestock”, authored by Donald Hansen, Extension Veterinarian, Oregon State University. This publication is available in the Cattle Producers Handbook (the Yellow Book) which is a product of the Extension Beef Cattle Resource Committee.
The first important evidence of Se deficiency has been aptly named “white muscle disease.” It involves muscle damage (myopathy), in the course of which calcium salts may be deposited among the muscle fibers in parts of the bodies of affected animals.
These salts give the involved areas a whitish appearance. Both skeletal muscles, such as those of the legs and back, and heart muscles may be affected. When skeletal muscles are affected, the animals may have difficulty walking and may be unable to rise and follow the herd. When the heart is affected, the animal may die from sudden heart failure.
Some animals show signs of respiratory distress, which may lead the owner to treat them for pneumonia.
They do not respond to antibiotic therapy, and death may occur because of fluid accumulation in the lungs. White muscle disease is most common in newborn lambs or calves, which will show clinical signs from birth to an age of 4 to 6 weeks. It occurs occasionally in yearlings or older animals.
Cows or ewes receiving a selenium-deficient diet during gestation may give birth to offspring suffering from this trace-mineral deficiency.
Their calves or lambs may be born dead or weak, and may die during the first few days of life. In cases of extreme deficiency, permanent damage may occur, and the newborn animals will not respond to selenium administration. The dams (females) need adequate selenium during gestation.
This is accomplished by injecting the pregnant cows or ewes with carefully calculated amounts of Se salts in sterile solution, or by providing an adequate Se source in the diet.
The oldest accepted method of providing needed selenium is by injection. Several preparations that contain both selenium and vitamin E are available commercially. The manufacturers of these have carefully calculated safe and effective dosage levels, and their recommendations should be followed closely.
Several other methods of selenium supplementation have been developed. Selenium may be given mixed in feed or in salt mixes offered to animals free choice. Based on research findings, the U.S. Food and Drug Administration (FDA) approved the addition of selenium to complete feeds at a level of 0.1 ppm in 1974.
Subsequently, it has increased the allowable limit to 0.3 ppm, with corresponding levels in salt mixes calculated on the proportion of salt intake to the total feed intake.
Selenium has also been given effectively in the form of heavy pellets, or “bullets” that lodge in the forestomach of ruminant animals and gradually release selenium to the animal.
Modern forage production practices tend to reduce the Se level in livestock feed.
To combat this, Se has been added in commercial fertilizers. This is an alternative method of Se supplementation that may provide an easier answer to Se deficiency problems at some future date, since it avoids handling the animals. Plants in general do not require selenium for normal growth, but its involvement in animal health has been dramatic and significant.
Selenium, like some other nutrient materials, is dangerous to animals if given in excess. The problem is especially critical with Se because the animal’s requirement is extremely low (in the area of 0.1 ppm of the diet dry matter; that is, 1/10-part Se per million parts of dry feed).
Excessive amounts of selenium are known to cause toxicity problems in animals, including death.
Trace minerals are the very important in keeping livestock healthy and performing optimally. Working with a nutritionist to develop a mineral program specifically tailored to your region and ranch — and working with a veterinarian if you suspect that health issues may be due to deficiency problems—can have a huge impact on your profit or loss when raising livestock.
