Effect of supplemental selenium and vitamin E on serum and milk content of cattle and sheep, tissue selenium content and mineral status of grazing cattle in north Florid

Four experiments were conducted in north Florida to evaluate the effect of supplemental selenium (Se) and vitamin E to beef cattle and sheep on serum concentrations of these nutrients on dams and their offspring. Similarly, Se concentrations in liver, milk and hair of cows as well as the mineral status of cattle based on forage, soil and animal tissue and fluid analysis were evaluated. For the first two experiments supplemental Se increased the overall Se status of grazing cattle in serum, liver, milk and hair. There was no effect of vitamin E on liver, milk, hair or serum Se concentrations of cows, but on serum Se concentrations of calves. Selenium untreated cows had higher serum vitamin E than Se treated cows. Except for low serum P in cows, overall mineral status of cattle was adequate in both experiments. Neither Se nor vitamin E had any effect on lymphocyte blastogenic response but the health status of the cattle was satisfactory. All soil samples were deficient in K and Se. Low concentrations of soil Mg, Zn, Mn, Cu and P were also recorded. Forage had greater concentrations of Ca, K, Na, Zn, Co, Mg and Cu during March-May than the rest of the year. The most deficient minerals in forage were: P, Na, Cu, Se, Co and Zn. In experiments 3 and 4 there was no effect of prepartum i.m. injections of Se and vitamin E on serum concentrations of these nutrients in cows, calves and ewes and the main variation was due to sampling periods (parturition, one month and two months). Brahman cows had higher serum vitamin E concentrations than crossbred cows. The lowest vitamin E concentrations in calves were recorded at birth and the highest at two months. The lowest serum Se concentrations of ewes were recorded in pre-treatment, and the lowest serum vitamin E were found one and two months after parturition. The highest serum vitamin E concentrations at birth were recorded in lambs from ewes treated with the highest vitamin E level (9 mg vitamin E/kg live weight). Colostrum from cows or ewes had higher Se concentrations than milk. Ewes treated with 1.5 mg Se and 4.5 mg vitamin E/kg live weight had higher colostrum Se concentrations than ewes without supplemental Se.