Intramuscular selenium administration in selenium-deficient cattle.

Nine recently weaned Hereford heifers were randomly assigned to a control group (n = 3) or a treatment group (n = 6). The animals were selenium (Se) deficient (mean +/- SD blood Se concentration = 0.024 +/- 0.012 microgram/mL). They were maintained on a selenium-deficient diet, and on day 0 of the study the treatment group was given 0.05 mg Se/kg body weight intramuscularly, while the control group received a placebo. The Se concentration of blood, serum, and urine as well as the glutathione peroxidase (GSH-Px) activity of blood and serum was measured over an 84-day period. Peak blood Se and serum Se concentrations (mean +/- SD) in the treatment group occurred at 5 hours postinjection and were 0.131 +/- 0.028 microgram/mL and 0.154 +/- 0.027 microgram/mL, respectively. The mean blood Se concentration of the treatment group was greater (P < .05) than that of the control group for the first 28 days after injection. The mean serum Se concentration of the treatment group was greater (P < .05) than that of the control group for all times after injection, except for day 56. The mean (+/- SD) blood GSH-Px activity of the treatment group (12.0 +/- 2.3 mU/min/mg hemoglobin) was increased (P < .05) over the control group (2.0 +/- 1.4 mU/min/mg hemoglobin) by day 28 and continued to be greater (P < .05) throughout the 84 day postinjection period.(ABSTRACT TRUNCATED AT 250 WORDS)