Cows fed supplementary selenium at 6 milligram per day had more rapid recovery from E. coli infections. Occasionally I hear of abortions in goats, so use caution. Generally, forages are not good sources of vitamin E because of storage loss. Forages will also be poor sources of selenium in the northeast and mid-Atlantic regions, and in those states listed above. In addition, only about 40 percent or less of fed selenium is actually absorbed by cattle, because of the interfering influence of some digestive factors and ingredients, especially calcium and a few other minerals.
Injections usually offer only short-term benefit.
This is a legal limit, according to the Food and Drug Administration, and it is recognized that selenium is toxic when taken in excess. Some years ago, the Food and Drug Administration recognized the legal supplementation limit of concentrate rations at the rate of 0.045 milligram per pound, because of the widespread selenium deficiency in U.S. soils and the demonstrated benefits in reproduction and mammary health of dairy animals. For long-term treatment other than in feed or by injection, the use of forestomach heavy pellets, glass boluses or osmotic pumps has become common for ruminants in some countries, especially Australia. In New Zealand, where the soil is selenium-deficient, fertilizer amendment to increase forage selenium levels has led to acceptable animal health. Sodium selenate rather than selenite is used, because it is more readily available for plants.