Efficacy of 1α hydroxyvitamin D3 in the prevention of bovine parturient paresis

Abstract

One hundred and seventeen Israeli-Friesian cows from herds with a milk fever incidence of more than 15 percent were injected intramuscularly with either 350 μg 1α hydroxyvitamin D3 (1αOHD₃) in propylene glycol or with the vehicle alone, close to calving. If parturition had not occurred within 72 hours a second injection was administered; parturition was induced two days after the second injection if necessary. There were 10 cases of milk fever among 57 control cows as opposed to two cases among the 60 animals treated with 1αOHD₃. In an attempt to prolong the effect of the drug, Israeli-Friesian cows were injected intramuscularly with 350 μg 1αOHD₃ in either 10 ml propylene glycol or arachis oil. 1αOHD₃ in arachis oil did not prolong the effect of the drug. 1αOHD₃ in propylene glycol increased plasma calcium concentrations more rapidly than when the drug was administered in oil. Additional cows of the same breed and age were injected intramuscularly with 350 μg 1αOHD₃ in propylene glycol. Five of the animals received a second dose four days, and five received a second dose five days after the first injection. Five animals served as uninjected controls. The plasma calcium levels of the injected cows were significantly higher (P<0.01) than those of the controls from the second until the 14th day after the first injection. Based on these results 451 Israeli-Friesian cows from herds with a milk fever incidence of more than 15 percent were injected intramuscularly with 1αOHD₃ close to calving. If parturtion had not occurred up to 100 hours later, a second injection was administered; parturition was induced two days after the second injection if necessary. There were 27 cases (6 percent) of milk fever among the 451 injected cows. The incidence in 68 animals injected less than one day before calving was 23.5 percent (16 cows). However, a significantly lower incidence (2.9 percent, P<0.01) occurred in the 383 cows which were injected more than one day before calving, with less than four days between the two injections of 1αOHD₃, and when parturition occurred not more than four days after the last injection of the drug either with or without induction of parturition.