The influence of supplements of selenite, selenate and selenium yeast on the selenium status of dairy heifers
Ortman, K.; Andersson, R.; Holst, H.
Acta Veterinaria Scandinavica 40(1): 23-34
1999
ISSN/ISBN: 0044-605X PMID: 10418193 Document Number: 500074
Twenty-four Swedish Red and White dairy heifers were not given supplementary Se for 6 months. The basic diet contained Se 0.026 mg/kg feed DM. After the deprivation period heifers were divided into 4 groups; groups I-III received 2 mg additional Se daily as sodium selenite, sodium selenate and a selenium yeast product, respectively. Group IV, the control group, received no additional Se. Total dietary Se content for groups I-III during the supplementation period was 0.25 mg/kg DM. After the deprivation period mean blood Se (640 nmol/litre) and plasma Se (299 nmol/litre) and the activity of GSH-Px in the erythrocytes (610 micro kat/litre) were marginal, but after 3 months of supplementation they were adequate in all 3 groups. Blood and plasma Se was significantly higher in group III than in groups I and II, but there was no significant difference between groups I and II. The activity of GSH-Px in the erythrocytes did not differ between the supplemented groups. Control heifers had significantly lower Se in the blood and plasma and lower GSH-Px activity in the erythrocytes than those in the supplemented groups. The activity of GSH-Px in platelets also increased with increased Se intake. While triiodothyronine levels did not differ between the groups, those of thyroxine were significantly higher in the unsupplemented control group.