Blood Calcium Dynamics after Prophylactic Treatment of Subclinical Hypocalcemia with Oral or Intravenous Calcium

Wednesday, July 23, 2014
Exhibit Hall AB (Kansas City Convention Center)
Cedric D Blanc , Pacific Rim Dairy, Corcoran, CA
Mark Van der List , Boehringer Ingelheim, St Joseph, CA
Sharif S Aly , VMTRC, University of California, Tulare, CA
Heidi A. Rossow , VMTRC, University of California, Tulare, CA
Noelia Silva-del-Rio , VMTRC, University of California, Tulare, CA
Abstract Text:

Total serum Ca dynamics and urine pH levels were evaluated after prophylactic treatment of subclinical hypocalcemia after parturition in thirty-tree multiparous Jersey/Holstein crossbreed cows.  Cows were blocked according to their calcemic status at the time of treatment (Vetscan 200-1000R, Abaxis) [normocalcemic (8.0- 9.9 mg/dl; n=15), or hypocalcemic (5.0-7.9 mg/dL; n=18)] and randomly assigned to one of three treatments: Control [ no Ca supplementation (n=11)]; intravenous Ca [Ca-IV (n=11), 500 mL of 23% Ca Gluconate (10.7g Ca, Durvet, Blue Springs, MO)]; and oral Ca [Ca-Oral (n=11), one oral bolus (Bovikalc bolus, Boehringer Ingelheim, St. Joseph, MO) containing CaCl2 and CaSO4 [43g Ca] two times 12 h apart].  Total serum Ca levels were evaluated at 0, 1, 2, 4, 8, 12, 16, 20, 24, 36 and 48 h after treatment application (Enzymatic Rate/Automated Chemistry Analyzer method, Marshfield lab, WI) and urine pH at 0, 1, 12, 24, 36, and 48 h (on-farm with Oakton pH Testr 20).  Overall, total serum Ca levels did not differ with treatment.  But, Ca-IV cows experienced a sharp increase in serum Ca levels after treatment (peak = 11.4 mg/dL at 1 h), followed by a steep decline (nadir = 6.4 mg/dL at 24 h).  Total serum Ca levels were higher for Ca-IV than control and Ca-Oral at 1, 2, and 4 h after treatment, but lower than Ca-Oral at 20, 24 and 36 h and control at 36 and 48 h.  Treatment, time and treatment by time interaction were significant for urine pH.  Mean urine pH was lower for Ca-Oral cows (6.69) than for control (7.52) and Ca-IV (7.19) cows.  Urine pH levels at 1 h after treatment were lower for Ca-IV compared to both Control and Ca-Oral.  At 12, 24, and 36 h, urine pH levels were lower for Ca-Oral compared to both Control and Ca-IV.  This was expected as the oral Ca supplementation used (Bovikalc) is designed as an acidifying agent.  Wide fluctuations in blood Ca are observed after prophylactic intravenous Ca supplementation in normo- and subclinical hypocalcemic cows.  The implications of these transient changes in serum Ca have still to be determined. 

Keywords: hypocalcemia, hypercalcemia, dairy cattle