M a n a g i n g M i n e r a l s - T h e Ba s i c s o f S e l e n i u m 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.
26 - The Boer Goat
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
