The levels of selenium and glutathione peroxidase activity in blood of sheep, cows and pigs.

The levels of selenium (Se) and glutathione peroxidase (GPX) in the blood of sheep, cows and pigs under farm conditions were examined. Sheep appear to form two distinct groups, namely high Se and GPX and low Se and GPX. The high group gave ranges of 133-249 ng/ml and 77-179 iu/g Hb for blood Se and GPX respectively, while the low group showed levels of 21-67 ng/ml and 2-20 iu/g Hb. Overall sheep blood showed a high correlation between Se and GPX (r = 0-92, P less than 0-001). Cow bloods formed one group, all having low Se and GPX levels except for a single outlier. Omitting this animal, the overall ranges were 9-72 ng/ml and 6-36 iu/g Hb for Se and GPX respectively. Blood Se and GPX activity were significantly correlated (r = 0-59, P less than 0-001). Pigs formed a single group also, with the difference that while their blood Se was high, the corresponding blood GPX activities were relatively low. Overall ranges were 93-193 ng/ml and 17-69 iu/g Hb for Se and GPX respectively. Correlation between blood Se level and GPX activity in this species was not significant (r = 0-27, P more than 0-1).