Selenium
- Sheep Bolus Company
- Aug 5
- 2 min read
Selenium may be the most studied mineral deficiency because of how crucial it is for overall ovine health & because a large portion of the US is deficient in it. “Selenium deficiency is a soil issue, especially in the West where many of the soils are a little too acidic, Taylor says. Either selenium is not present or it exists in a form that the plants can’t absorb.
“Because the selenium in the vegetation is so low, animals can’t meet their daily selenium requirement,” he adds. “They just can’t eat enough plants in 24 hours to get what they really need.” [1]
The most well known result of selenium deficiency is white muscle disease (WMD) in lambs as well as nutritional muscular dystrophy, and stiff lamb disease.
WMD is common to see in 2-6 weeks old lambs. It can also be observed at lambing if the mother was selenium deficient during gestation. Fast growing meat breeds like Suffolks & Texels are prone to it. The lamb will display symptoms of stiffness & within 48 hours will be unable to get up.
Early embryonic loss/miscarriage is attributed to selenium deficiency. Higher rates of fertility have been associated with supplementing ewes with selenium prior to breeding.
Keep in mind that selenium is most effective in conjunction with Vitamin E. Green pasture is rich in Vit E. High quality hay under a year old also contains Vit E. If either of these are missing then it is necessary to consider alternative sources so that selenium supplementation is effective. Treatment can include injections of BoSe (selenium/vitamin E available from a vet), a gel from the feed store, selenium yeasts, minerals containing selenium, or a bolus containing selenium. There are pros & cons to each of these ranging from bioavailability to monitoring intake levels in free access.
“Selenium, a trace mineral and component of important selenoprotein antioxidants, is essential for good health in livestock and humans. If the body cannot form these important antioxidant proteins, it predisposes the animal to sickness and eventually death at a young age.
Selenium deficiency in livestock affects more than 35 states and costs sheep, beef, and dairy producers an estimated $545 million in losses each year. Lack of adequate selenium in sheep reduces conception rates, increases neonatal mortality, and in some instances, causes white muscle disease—nutritional muscular dystrophy. Lambs that do survive suffer from increased disease, reduced weight gain, and impaired performance.” [1]
It is important to note that sheep can develop toxicity if too much selenium is given. It is good to learn if your area is low or high in selenium. This will help you to decide what degree of supplementation your flock requires. Consider consulting regional US Geological Survey maps (USGS.gov), contacting your local extension office, or having soil & water testing done.
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