Observations of the use of 1 alpha hydroxycholecalciferol in the prevention of bovine parturient paresis

Abstract

Varying doses of 1 alpha-hydroxycholecalciferol (1 alpha-HCC) (50, 150, 250 and 350 micrograms) in propylene glycol were injected intramuscularly into 30 dry adult Israeli Friesian cows. Fourteen of these animals received a second dose; four were given 250 or 350 micrograms 48 hours after the first dose and 10 were given 350 micrograms 72 hours after the first dose. Plasma calcium rose after 24 hours at all dose levels except 50 micrograms. A dose-dependent peak in plasma calcium was reached after three to four days, followed by a return to baseline five days (150 micrograms) and eight days (250 and 350 micrograms) post injection respectively. Repeating the injection 48 or 72 hours later increased the time span by three and four days respectively. The effect of plasma inorganic phosphate was double that on plasma calcium. Plasma magnesium declined slightly three days post injection. High calcium feeding in conjunction with one or two injections of 350 micrograms 1 alpha-HCC did not modify the response of plasma calcium. An injection of 350 micrograms of 1 alpha-HCC was given once to 40 parturient paresis-prone cows of the same breed and twice at 72-hour intervals to 37 such cows. Six of the animals received 5 mg of flumethasone together with the second injection and 13 received it 48 hours later. This was to induce parturition, which occurred within 24 to 48 hours. None of the cows injected earlier than 24 hours prepartum developed parturient paresis in comparison with 22 out of 60 control animals which did. The results suggest that 1 alpha-HCC is useful in the prevention of bovine parturient paresis.