2002 Volume 55 Issue 4 Pages 219-222
The effects of ammonium chloride orally administered to prevent hypocalcemia at parturition in Holstein dairy cows were studied. Ammonium chloride (60g/head/day) was administered to 3 cows for 2 weeks prior to the day of calving. No ammonium chloride was administered to 3 control cows. In the control group, totalcalcium (Ca) and ionized-calcium (iCa) concentrations were significantly lower at parturition (Ca: 6.1±2.6mg/dl, iCa: 0.93±0.40mmol/l) than in the pre-parturition period (Ca: 8.9±0.5mg/dl, iCa: 1.27±0.04mmol/l). In the treated group, on the other hand, no significant changes in Ca and iCa were observed. Urinary pH of cows given ammonium chloride decreased significantly from a pre-value of 8.6±0.3 to 7.5±0.3 at calving. No significant differences were observed between the groups in any serum biochemical parameters other than Ca and iCa. These findings indicate that ammonium chloride (60g/head/day) may be orally administered safely to dairy dry cows to prevent hypocalcemia.
