1 alpha-hydroxycholecalciferol for the treatment of the downer cow syndrome.

Seventeen Holstein cows that showed clinical and biochemical symptoms (hypocalcemia and hypophosphatemia) of parturient hypocalcemia within 48 h postcalving and did not respond to Ca therapy were divided into two groups. Eight cows received a second intravenous Ca infusion 24 h after the first one. This treatment increased plasma Ca concentration but had no significant effect on phosphatemia, and the cows remained unable to rise and stand during 48 h following this second Ca infusion. The 9 other cows received 1 alpha-hydroxycholecalciferol (1 microgram/kg of BW, half the dose intravenously, the other half intramuscularly). 1 alpha-Hydroxycholecalciferol induced a significant increase in plasma P concentration and recovery of all the 9 cows within 12 h after this treatment.