Effect of Supplemental Selenium for Beef Cows on the Performance and Tissue Selenium Concentrations of Cows and Suckling Calves

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Abstract
The effect of supplemental dietary selenium on tissue selenium concentrations in cows and their nursing calves was determined. In Exp. 1, beef cows were fed one of two protein supplements, a soybean meal-corn meal mixture or linseed meal at the equivalent of 908 g/head/day. The soybean meal-corn meal mixture contained 98 ppb selenium and the linseed meal, 1,186 ppb selenium on a dry matter basis. Five treatments were used, with three or four cows and their calves assigned to each. The treatments were (1) soybean meal-corn meal supplement alone and (2 and 3) in combination with the equivalent of .1 or .2 ppm added selenium in the total diet, and (4) the linseed meal supplement alone and (5) in combination with the equivalent of .5 ppm added selenium in the total diet. The added selenium, either in the form of linseed meal or as inorganic sodium selenite, tended to increase concentrations of selenium in the plasma, milk and liver of the cows and in the plasma, muscle and liver of the calves. Tissue selenium concentrations of calves were greater (P<.01) with linseed meal alone than with a comparable selenium intake from soybean meal plus inorganic sodium selenite. Linseed meal plus the equivalent of .5 ppm selenium in the total diet resulted in the greatest tissue concentrations for both cows and calves, except in the kidney, which was not influenced. In Exp. 2, cows were fed free-choice mineral supplements containing levels of selenium calculated to provide intakes similar to those provided in Exp. 1. Soybean meal and linseed meal were used as protein supplements. Serum selenium concentrations of cows shortly after calving were increased by selenium supplementation, but concentrations in milk at 2 and 8 weeks after calving were not altered. Liver and muscle selenium concentrations were lowest for calves from cows fed soybean meal. Supplementation with the equivalent of .1 or .2 ppm selenium in the total diet did not increase (P>.10) tissue selenium concentrations above those of calves from cows fed linseed meal. Supplementing linseed meal with .5 ppm selenium increased (P<.05) liver and muscle selenium concentrations of the calves. Supplemental selenium can be provided at a dietary level of .1 ppm without adversely affecting animal or human health. Dry protein supplements or palatable mineral mixtures appear to be feasible vehicles for providing selenium to cows on pasture. Copyright © 1981. American Society of Animal Science . Copyright 1981 by American Society of Animal Science.