title: Blood calcium dynamics after prophylactic treatment of subclinical hypocalcemia with oral or intravenous calcium.
abstract: Total serum Ca dynamics and urine pH levels were evaluated after prophylactic treatment of subclinical hypocalcemia after parturition in 33 multiparous Jersey × Holstein crossbreed cows. Cows were blocked according to their calcemic status at the time of treatment [normocalcemic (8.0-9.9 mg/dL; n = 15) or hypocalcemic (5.0-7.9 mg/dL; n = 18)] and randomly assigned to 1 of 3 treatments: control [no Ca supplementation (n = 11)]; intravenous Ca [Ca-IV (n = 11), 500 mL of 23% calcium gluconate (10.7 g of Ca and 17.5 g of boric acid as a solubilizing agent; Durvet, Blue Springs, MO)]; or oral Ca [Ca-Oral (n = 11), 1 oral bolus (Bovikalc bolus, Boehringer Ingelheim, St. Joseph, MO) containing CaCl2 and CaSO4 (43 g of Ca) 2 times 12h apart]. Total serum Ca levels were evaluated at 0, 1, 2, 4, 8, 12, 16, 20, 24, 36, and 48 h, and urine pH was evaluated at 0, 1, 12, 24, 36, and 4 8h after treatment initiation. Total serum Ca levels were higher for Ca-IV than for control and Ca-Oral cows at 1, 2, and 4h after treatment initiation, but lower than Ca-Oral cows at 20, 24, and 36 h and lower than control cows at 36 and 48 h. At 1h after treatment initiation, when serum Ca levels for Ca-IV cows peaked (11.4 mg/dL), a greater proportion of Ca-IV (n = 8) cows had total serum Ca levels >10mg/dL than control (n = 0) and Ca-Oral (n = 1) cows. At 24h after treatment initiation, when Ca-IV cows reached the total serum Ca nadir (6.4 mg/dL), a greater proportion of Ca-IV (n = 10) cows had serum Ca levels <8 mg/dL than control (n = 5) and Ca-Oral (n = 2) cows. Treatment, time, and treatment × 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 1h after treatment were lower for Ca-IV cows compared with both control and Ca-Oral cows, a finding likely associated with the iatrogenic administration of boric acid added as a solubilizing agent of the intravenous Ca solution used. At 12, 24, and 36 h, urine pH levels were lower for Ca-Oral cows compared with both control and Ca-IV cows. This was expected because the oral Ca supplementation used (Bovikalc) is designed as an acidifying agent. Wide fluctuations in blood Ca were observed after prophylactic intravenous Ca supplementation. The implications for milk production and animal health, if any, of these transient changes in total serum Ca have yet to be evaluated.
authors.affiliation: Pacific Rim Dairy, 13406 Road 24 Corcoran, CA 93212.
authors.forename: C D
authors.initials: CD
authors.lastname: Blanc
authors.affiliation: Boehringer Ingelheim, 5501 Corporate Dr., St. Joseph, MO 64507.
authors.forename: M
authors.initials: M
authors.lastname: Van der List
authors.affiliation: Veterinary Medicine Teaching and Research Center, 18830 Road 112, Tulare, CA 93274; Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis 95616.
authors.forename: S S
authors.initials: SS
authors.lastname: Aly
authors.affiliation: Veterinary Medicine Teaching and Research Center, 18830 Road 112, Tulare, CA 93274; Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis 95616.
authors.forename: H A
authors.initials: HA
authors.lastname: Rossow
authors.affiliation: Veterinary Medicine Teaching and Research Center, 18830 Road 112, Tulare, CA 93274; Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis 95616. Electronic address: nsilvadelrio@ucdavis.edu.
authors.forename: N
authors.initials: N
authors.lastname: Silva-del-Río
mesh_terms: D061605:Administration, Intravenous; D000284:Administration, Oral; D000818:Animals; D002118:Calcium / Q000008:administration & dosage / Q000097:blood*; D002136:Calcium, Dietary / Q000008:administration & dosage / Q000009:adverse effects; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy* / Q000517:prevention & control; D019587:Dietary Supplements; D005260:Female; D006706:Homeostasis; D006863:Hydrogen-Ion Concentration; D006934:Hypercalcemia / Q000139:chemically induced / Q000662:veterinary*; D006996:Hypocalcemia / Q000188:drug therapy / Q000517:prevention & control / Q000662:veterinary*; D010298:Parity; D036801:Parturition; D011644:Puerperal Disorders / Q000188:drug therapy / Q000517:prevention & control / Q000662:veterinary*; D014556:Urine / Q000737:chemistry
chemical_list: D002136:Calcium, Dietary; D002118:Calcium
keywords: calcium homeostasis; hypercalcemia; hypocalcemia