Calcium metabolism in cows receiving an intramuscular injection of 1,25-dihydroxyvitamin D3 combined with prostaglandin F2alpha closely before parturition

To determine the effect of exogenous 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] combined with induced parturition on calcium (Ca) metabolism, cows received a single intramuscular injection of 1,25(OH)2D3 and prostaglandin F2alpha (PGF2alpha) closely before calving. Ten late-pregnant, multiparous Holstein cows were assigned to 1,25(OH)2D3 group (five treated with both 1,25(OH)2D3 and PGF2alpha) and control group (five treated with PGF2alpha). 1,25(OH)2D3 group showed an increase in plasma Ca concentration around parturition, whereas control group revealed a decrease in plasma Ca level. Plasma Ca concentration in 1,25(OH)2D3 group were significantly higher than that in control group during .0.5 to 3 days after parturition.