Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 6/29/1998
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: The effect of dietary selenium (Se) intake on concentration of triiodothyronine (T3) and thyroxine (T4) in plasma, and immunoglobulins (IgG and IgM) in plasma and colostrum of cows was determined. Pregnant cows (n=45) were randomly allocated among three dietary treatments of 20, 60 and 120 ppm Se as selenite in salts offered free-choice. At parturition, cows given salt with 20 ppm Se and lower (P<.05) concentrations of Se in blood compared to cows with access to higher Se salts. Treatment affected (P<.01) the concentration of T3 and the ratio of T3 to T4 in plasma of cows. Plasma IgG in cows and calves, colostrum, and Se concentrations in colostrum, casein and whey were lowest (P<.01) for cows given salt with only 20 ppm Se. The concentrations of Se in the protein fractions within serum were not affected by treatment. Within serum, the highest concentrations of Se were in the selenoprotein P fraction (31.6 ng/ml), the smallest concentrations were in the glutathione peroxidase (GPX) fraction (4.7 ng/ml) and an intermediate amount of Se was obtained form the albumin fraction (8.5 ng/ml). In conclusion, consideration should be given to the concentrations of T3 and IgG when determining the nutritional requirements for Se in cattle.