In a two year experiment, Angus cows were supplemented with selenium through salt free-choice mineral mixes (yeast form) and two injectable products, Deposel? (barium selenate, long lasting) and Mu-Se? (sodium selenite, short lasting). Plasma selenium levels increased in the two salt mineral mix treatments, whereas in the Mu-Se treatment the values decreased, while the Deposel was able to maintain selenium concentrations. Plasma concentrations in the control were below critical levels (0.03 g/ml) at the end of the experiment (24 mo) and at the critical level at 18 mo. Plasma values in the Mu-Se treatment were at critical levels at 18 mo and above critical but below adequate at the start and at 6, 12 and 24 mo. The Deposel treatment attained adequacy (0.07 ?g/ml) in plasma selenium at 6 mo and at no time was less than the critical level (0.03 g/ml). Liver selenium concentrations of the control did not attain adequate levels (1.2 mg/kg) during the 2 years, and even though the Deposel treatment reached adequacy only at 24 mo the trend for this treatment was to increase liver selenium concentrations with time. The Mu-Se treatment at no time presented adequate concentrations. The two free-choice salt mineral mixture treatments were found to provide adequate selenium in liver at 6, 12 and 24 mo after treatment began. Colostrum selenium concentrations decreased from the first to the second year, and at no time did any treatment reach adequacy (0.1 mg/L). Milk selenium concentrations declined from 60 to 180 days in the control during the first year, but the concentrations tended to be maintained in all supplemented treatments. During the second year, the selenium concentrations for the Mu-Se treatment declined, while the concentrations were maintained in the Deposel and both free-choice mineral mixture treatments. Deposel provided long lasting reliable protection from selenium deficiency while the yeast form of selenium provided continuous and highest levels ofblood, liver and milk selenium concentrations.
|Number of pages||7|
|Journal||Journal of Animal and Veterinary Advances|
|Publication status||Published - 2003|