The objective of this study was to determine the effect of either oral supplementation of sodium selenite and alpha-tocopherol or intramuscular administration of a commercial preparation of selenium (Se) and vitamin E to Standardbred broodmares with low (21.0 ± 18.1 IU/g Hb) whole blood glutathione peroxidase (GPx) activity. Ten mares received 3 weekly intramuscular (IM) doses, whereas 9 mares were orally supplemented daily for 10 wk. Blood samples were collected via jugular venipuncture and the whole blood GPx activity was measured at each sampling time for the 32-week period. Both oral and intramuscular administration resulted in a marked increase in whole blood GPx activity in both groups of mares.
Baird et al. (Thu,) studied this question.