Selenium in milk from feeding small supplements.

Supplements of 0, 1, 2, or 5 mg of selenium from sodium selenite fed per cow daily from 90 days prepartum through approximately 6 mo of lactation had no significant effect on selenium in milk of Hereford cows. Selenium in milk was assayed 2 to 3 days postpartum (average of .014 to .023 ppm) and approximately 3 mo post parturition (average of .016 to .021 ppm). The basal diet consisted of medium quality grass-legume hay (.069 mg/kg), ad libitum liquid supplement (.152 mg/kg), and 1.36 kg shelled corn (.018 mg/kg) starting in early lactation. Treatments of selenium were administered via free-choice liquid supplement.