Selenium Supplementation For Goats
Selenium is an essential trace mineral for goats and for livestock in general (“trace” means required in small amounts). If you are raising goats in areas where the soils are deficient in selenium, you need to provide it to goats via supplements. Why? Selenium (Se) is important for growth, reproduction and immune function. Symptoms of selenium deficiency include failure to gain weight, growth depression, decreased twins/triplets, reduced fertility, reduced kid weights, reduced kid vigor, and increases in susceptibility to bacterial and viral infections (for example – foot rot). Selenium deficiency can cause poor goat performance and can result in white muscle disease (WMD). Note: WMD is caused by a deficiency of selenium and/or vitamin E. Interestingly, selenium and vitamin E deficiency is not always readily observable so supplementation is a good idea. However, selenium is the ONLY micronutrient regulated as a feed additive by the Food and Drug Administration (FDA) because of its toxic effects when animals ingest certain formulations in excess. Thus, it is important to understand Se supplementation to protect the health of your herd
Selenium deficiency in goats is associated with selenium deficient soils and the inadequate uptake of selenium by forages grown on these soils. If the soil is deficient in selenium, the forage your goats eat will also be deficient in selenium leading to deficiencies in your herd. Selenium levels in soil vary dramatically regionally. A map showing selenium can be found at (https://mrdata.usgs.gov/geochem/doc/averages/se/usa.html). Vitamin E deficiency is independent of soil type and is more closely related to forage quality. Fresh legumes and pasture are are good sources of vitamin E and stored feeds tend to be poor sources of vitamin E. Stored feeds can lose up to 50% of their vitamin E per month. All breeds of goats are susceptible to WMD (white muscle disease) but it is most common in newborns or fast growing young animals.
Symptoms. The disease (WMD) affects both the skeletal and the cardiac muscles. Skeletal symptoms vary from stiffness to obvious pain when walking or an inability to stand. Kids may tremble in pain when held in a standing position. Hunched animals with a stiff gait are also common. Deficiencies occur in newborns, they are born weak and may not be able to get to their feet. Adult deficient animals may have poor conception rates, abortions, stillbirths and miscarriages, retained placentas, or deliver weak kids. Cardiac symptoms can appear to be pneumonia like. They include difficulty breathing, frothy nasal discharge, and fever. Heart rate and respiratory rate are elevated and irregular. Both the skeletal and the cardia types often occur at the same time.
It all sounds bad, doesn’t it? The good news is that when WMD affects the skeletal muscles it can be treated with supplemental selenium and vitamin E. Animals typically respond within 24 hours. Cardiac muscle damage is often permanent.
Conclusion. WMD can be prevented by supplementing selenium and Vitamin E in areas where soils are deficient. Total daily consumption of selenium must not exceed 0.7 mg/head/day. Ideally, the total diet for goats should contain between 0.10 to 0,3 ppm of selenium. There are several forms of selenium available as a supplement. We utilize a free choice “goat block” that contains a small amount of selenium. Additionally, we administer a selenium and vitamin E gel every 1-2 months. Injectable forms are also available as a Rx but we do not utilize this form due to the potential to overdose.
We recently were asked, “how do I know if I have too much selenium in my goats diet“? Good question! This is how you can calculate how much selenium you are feeding your goats. First, you will need to look at the selenium content of your all your forages, grains, goat block, and other feeds and supplements. Once you know the amount of selenium in each part of the diet you can calculate the amount of selenium you are feeding.
Example: Our goats weigh 100 pounds and are eating a total of 5 pounds of dry matter daily (4 pounds of alfalfa, .75 pound of grain mix, and .25 pounds of goat block.
Alfalfa; 4 lb (1.8 kg) x 0.523 ppm Se = 0.94 mg Se
Grain mix: .74 lb (0.34 kg) x 0.18 ppm Se = 0.06 mg Se
Goat Block: .25 lb (0.11 kg) x 1.2 ppm Se = 0.03 mg Se
Selenium gel (once every 30 days): 4 gm (.004 kg) x 2 ppm/30 days = 0.0003 mg Se
Total: 0.94 + 0.06 + 0.03 + 0.0003 = 1.03 mg Se in total diet (5 lb. DM = 2.27 kg DM)
Total ppm in diet – 1.03/2.27 = .45 ppm Se
The National Resource Council (2007) reports that the maximum tolerable concentration of selenium is 5 ppm for goats (5 mg/kg). So, this diet does not exceed the maximum tolerable concentration.
It is important to remember, depending on your area grains and forages can be higher in selenium. Be sure to check your feed and supplement labels and even consider getting your forages tested to determine Selenium levels.