Study of combined injections of 1 alpha-hydroxy-cholecaldiferol and cloprostenol in the prevention of parturient paresis.

Dairy cows were injected with 1 alpha-hydroxycholecalciferol (1 alpha-HCC) and, or, cloprostenol at 275 days of gestation. Blood samples were taken daily from 270 days of gestation until seven days after parturition and analysed for calcium, inorganic phosphate, magnesium and hydroxyproline. In all treated and control cows concentrations of calcium, inorganic phosphate and magnesium decreased around the time of parturition. Concentrations of hydroxyproline increased from the second to the fourth day after parturition. This increase was slightly smaller in cows injected with cloprostenol but was unaffected by 1 alpha-HCC. There was a greater indicence of retained placenta and endometritis in cows receiving cloprostenol. The injection of cloprostenol with 1 alpha-HCC at 275 days of gestation did not prevent milk fever.