The effect of zinc supplementation on serum cancentration of zinc, vitamin A and β - carotane in dairy cow

This study has been done in order to assess the supplementation of zinc sulfate on serum level of vitamin A and Beta carotene in dairy cows. 17 heads of milky cows with equal conditions of feed management and production and coeval were located in two control group (7 heads) treatment group (10 heads). In treatment group in addition to normal food, 500 mg supplement zinc sulfate has added to diet for 45 days. Blood samples were taken in days zero (before of initial administration supplement), 15, 30 and 45 from cows in both groups of tail vein. Average zinc serum by biochemical kit and serum quantity of vitamin A and Beta- carotene by spectrophatometry and using N. Hexane solution were measured. The average of serum level of supplement group in comparision to control group in 15, 30, 45 days, shows meaningful increase (p=0/000). Average serum level of vitamin A in supplement group in 15 days didnt has significant increase, but in 30 and 45 days had significant increase (p=0/016, p=0/004, respectively). Serum Betacarotene in creased after day 15 in supplement group but any time that was not meaning increase but in 30 and 45 days had meaningful increase. (P=0.016, P=0.004). Serum Betacarotene incrased after day 15 in care group but any time, that was not meaningful increase. In supplement group the correlation between serum level of vitamin A with serum level of zinc was meaningful only day 45. (r= 0.716, p<0.05), In other times it was not meaningful, but in the case of Betacarotene, There wasnt meaningful relation with zinc serum. The result is that, zinc sulfate complementary increases serum level of zinc and vitamin A in milky cows and can be useful.