The effect of subcutaneous injection of calcium borogluconate on serum levels of calcium, phosphorus and magnesium in newly calved cows

Abstract

We assessed the levels of serum calcium (Ca), phosphorus (P) and magnesium (Mg) during the postpartum hours in adult Holstein-Friesian cows who received subcutaneous calcium borogluconate (CBG) post-calving. Fifteen cows were fed a 3-week close-up ration containing 63 g/day Ca and 40 g/day P, with a dietary cation–anion difference of 335 meq/kg DM. Within 30 min after calving, seven cows were injected 200 ml of a 40% CBG solution (6 g of Ca) subcutaneously and 8 cows were considered as controls. All cows were sampled from the jugular vein at calving time (before injection) and at hours 4 and 12 post-calving. Sera were analysed for Ca, P and Mg. In the experiment group, serum Ca remained almost constant within the physiologic limit (2.00–2.63 mmol/l) while the control group showed a linear decrease (P < 0.060) to levels below the hypocalcaemia limit of 2.00 mmol/l. The trends were statistically different between groups (P < 0.044). Calcium concentrations were different between groups at 12 h, P < 0.081. Except quadratic changes in P concentrations at P < 0.091 in the experiment group, the changes were not significant within or between groups, although the control group was hypophosphataemic during the post-calving hours. Magnesium concentrations were equally high in both groups with non-significant changes and differences within or between groups. At 12 h postpartum, two cows in the experiment group and four cows in the control group had serum Ca levels below 2 mmol/l. One cow in each group developed milk fever. It took 36 h in the experiment group and 12 h in the control group before the onset of clinical signs. Subcutaneous injection of CBG immediately postpartum may be helpful in stabilizing blood Ca and probably P during the postpartum hours. Additional studies are warranted to obtain more conclusive statistical results.