Managing Minerals - Selenium

Managing Minerals The Basics of Selenium

by Karla Blackstock

Managing minerals is a year-round job in the goat business. Trace minerals, such as copper, selenium and zinc, are essential components of any domestic livestock species, and supplementation of these minerals can have a positive effect on your herd’s reproduction, disease resistance and feed intake.

Some minerals are more important at different developmental stages and at different times of the year. To give these minerals a full glance, the next few issues will highlight minerals and their importance. The first of this series highlights selenium.

Selenium plays a critical role in the growth of newborns, fertility of breeding animals and in the prevention of diseases. Because of its role in muscle development, deficiency of this mineral typically presents itself as muscle impairments.

Deficiency Symptoms and Diseases

Signs of selenium deficiency include white muscle disease, reproductive disorders (embryonic mortality, infertility and retained placenta), impaired immune function and growth impairment.

Because selenium is involved in the immune system response, deficiencies or imbalances can reduce disease resistance. Stress induced by giving birth, milking, weaning and transport has been shown to decrease the ability of the animal to immunologically respond. Proper amounts of selenium in a goat’s diet can adequately counteract these stressful times.

However, selenium is closely linked to a number of vitamins, including A, D and E. Vitamin E and selenium are both involved in a variety of metabolic processes, and both nutrients are required to protect tissue membranes from being damaged.

“Selenium and vitamin E are synergistic,” said Coni Ross, ABGA judge and owner of CR Ranch. “When animals are exhibiting symptoms for selenium deficiency, you also need to consider vitamin E deficiency.”

Ross also said that harsh winters and droughts can cause goats to be deficient in minerals and vitamins. This also is true, she said, for goats raised in confinement.

Vitamin E deficiency has also been found in studies to increase the amount of selenium that is needed to increase stress tolerance, which is why you find vitamin E formulated into many selenium supplements.

In addition to the goat’s need for selenium for a healthy immune system (and disease resistance), there are a number of diseases or problems that can occur as a result of selenium deficiency.

White Muscle Disease

White muscle disease is a degeneration of muscles and is the major sign of selenium deficiency in ruminant animals, including newborn goats. White muscle disease can develop during gestation or after birth. Kids that have general weakness or stiffness should be evaluated for white muscle disease. In mild cases or in the beginning stages of the degeneration, kids will have a difficulty standing. In these cases, immediate selenium and vitamin E supplementation may improve the kid’s health.

Many times when a kid has white muscle disease, it is found because it stopped milking or is cold and unresponsive. Kids found in this state should be warmed prior to feeding. Seek medical advice if necessary.

Decreased Sucking Reflex

Kids that are deficient in selenium from gestation will also have a decreased sucking reflex. While there are other factors for kids with a decreased or unenthusiastic sucking reflex, evaluate these kids for a selenium or vitamin E deficiency.

Kids that are born “spraddle legged” (either back or back and front legs splayed out) with an inability to rise are usually vitamin E deficient. Treating these kids with vitamin E is easy and may be just what they need.

“You can buy regular 400 iu gel caps from a local grocery store, poke a hole in it with a needle and give it orally,” Ross said.

Retained Placenta

While there are a number of causes of a retained placenta, nutritional deficiencies, such as selenium and vitamins A and E, are a likely culprit. Supplementing with selenium and

vitamins A, D & E during the last few weeks of gestation will increase the body’s response to stress and could have a positive impact on the overall birthing process. Additionally, kids’ born to mothers who have been supplemented are less likely to develop white muscle disease. Supplementation

At one time, the FDA prohibited the addition of supplemental selenium in livestock feeds. However, current supplementation is .3 ppm for all livestock diets and free-choice mineral supplementation is currently 12 ppm for goats (not to exceed .7 mg/head/day).

Approved FDA sources for supplemental usage for goats include sodium selenite and sodium selenite with organic yeast. Free-choice minerals that are formulated for goats should be offered year-round and have sufficient selenium. Injectable selenium supplements can be prescribed by your veterinarian if necessary. And, a vitamin supplement for A, D and E can be found in a paste or in an injectable.

Selenium Toxicity

Selenium in high amounts can be toxic to animal of all species so it is critical to know what your soils hold before supplementing with high doses of any minerals.

“Giving selenium in non-deficient areas of the country can by risky,” said Ross. “You should always pay close attention to levels in your soils before supplementing with high doses of mineral.”

In the case of selenium toxicity, symptoms include emaciation, loss of hair, soreness and sloughing of the hooves, excessive salivation and blindness. Most cases of selenium toxicity are found in areas where selenium is found in soils. To find out the selenium, or other mineral, level in your soils, you can contact your local USDA or Extension office.

Selenium in Counties of the Conterminous States

For an interactive map of selenium concentration by county, go to: http://mrdata.usgs.gov/geochem/doc/averages/se/usa.html