tailieunhanh - Báo cáo khoa học: "Serum Calcium Response Following Oral Zinc Oxide Administrations in Dairy Cows"

Tuyển tập các báo cáo nghiên cứu về bệnh thú y được đăng trên tạp chí y học General Psychiatry cung cấp cho các bạn kiến thức về ngành thú y đề tài: Serum Calcium Response Following Oral Zinc Oxide Administrations in Dairy Cows. | Acta vet. scand. 2001 42 271-278. Serum Calcium Response Following Oral Zinc Oxide Administrations in Dairy Cows By T. Thilsing-Hansen and . Jorgensen The Royal Veterinary and Agricultural University Department of Clinical Studies Cattle Production Medicine Research Group Denmark. Thilsing-Hansen T Jorgensen RJ Serum calcium response following oral zinc oxide administrations in dairy cows. Acta vet. scand. 2001 42 271-278. - Six nonpregnant cows were allocated into 3 groups. Group 1 comprised a pair of lactating cows whereas groups 2 and 3 each comprised a pair of non-lactating cows. The cows in groups 1 and 2 were dosed intraruminally by stomach tube with zinc oxide at 120 mg Zn per kg of bodyweight at weekly intervals for a period of 33 days. Each cow received a total of 4 doses of zinc oxide. Group 3 served as non-treated control group. Blood samples were collected from all 6 cows daily. Serum was analysed for concentration of calcium. Within 12-24 h of each zinc oxide administration the serum calcium of the lactating cows dropped dramatically indicating the existence of an antagonistic effect between Zn and Ca. The first Zn induced hypocalcaemic episode in the lactating cows was followed by a rise in serum calcium to a level above the pre-dosing level and above the mean value of the control group. The depth of the hypocalcaemic response decreased with the number of zinc oxide dosings. This effect was explained as a response from the stimulation of the calcium homeostatic mechanisms. In the Zn dosed non-lactating cows responses were similar but less clear. The perspective of these findings is discussed in relation to resistance towards parturient hypocalcaemia. hypocalcaemia. Introduction There are several published reports documenting interaction between zinc and calcium in pigs chickens and rats. Newland et al. 1958 found a higher rate of zinc metabolism in pigs receiving high-calcium diets unsupplemented with zinc. Hoekstra et al. 1956 cured parakeratosis