EFFECTS OF ORAL DOSING WITH CALCIUM PROPIONATE ON TOTAL CALCIUM AND GLUCOSE-CONCENTRATIONS IN THE PLASMA OF THE COW

This study aimed to determine the effect of oral drenching with molass es, calcium propionate and MgO on plasma glucose and calcium concentra tions of dairy cows. Four trials were undertaken, each using three lac tating and three non-lactating Jersey cows. In Trial 1, the effect of drenching with 200 ml molasses was measured. Trial 2 measured the effe ct of a single treatment with 349 g calcium propionate in 200 ml molas ses. In Trial 3, the effect of 60 g MgO in molasses alone and in combi nation with calcium propionate was measured. Trial 4 tested the effect of repeating treatments with 349 g calcium propionate in 200 ml molas ses 24 h apart. Dosing with 349 g calcium propionate in molasses incre ased plasma total calcium (Ca-tot) concentration by 10% in lactating a nd non-lactating cows for periods less than 7 h, and this was not augm ented by simultaneous administration of MgO or treatment 24 h earlier with 349 g calcium propionate in molasses. Treatment with 200 mi molas ses alone resulted in increased plasma Ca-tot of 7%. Plasma glucose co ncentrations were elevated by 11% for less than 3 h after treatment wi th calcium propionate. For the prevention of subclinical hypocalcaemia and ketosis in early lactation, drenching with calcium propionate sol utions is unlikely to be of value due to the short duration of its eff ects, but the inclusion of calcium propionate in the postpartum ration deserves further investigation.