Serum Levels of Ionized Calcium, Vitamin D3, and Parathyroid Hormone of Captive Thick-Billed Parrots (Rhynchopsitta pachyrhyncha)
American Association of Zoo Veterinarians Conference 2003
Lauren L. Howard1,2, DVM; Philip H. Kass3, DVM, PhD, DACVPM; Nadine Lamberski4, DVM; Ray F. Wack2,5, DVM, DACZM
1Zoological Society of San Diego, San Diego, CA, USA; 2Zoological Medicine Clinical Services, School of Veterinary Medicine, University of California, Davis, CA, USA; 3Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA, USA; 4San Diego Wild Animal Park, Escondido, CA, USA; 5Sacramento Zoological Park, Sacramento, CA, USA
Abstract
Serum collected from 68 thick-billed parrots (TBP, Rhynchopsitta pachyrhyncha) was analyzed for ionized calcium (iCa), total calcium (tCa), phosphorus (P), total protein (TP), albumin (Alb), parathyroid hormone (PTH), and vitamin D3 (25[OH]D3). Ranges established were: iCa (0.82–1.3 mmol/L), tCa (5.5–8.4 mg/dl), P (1.08–5.43 mg/dl), TP (2.1–3.9 g/dl), Alb (0.9–1.3 g/dl), PTH (0–65.68 pmol/L), 25[OH]D3 (5.2–51 nmol/L). Sixty percent (±7.5%) of total calcium was ionized. Female TBP had significantly higher mean iCa (1.11 mmol/L), compared to males (1.05 mmol/L). Total calcium and iCa values in TBP were lower than reported reference values for other avian species. A significant positive linear relationship existed between Alb/TP and iCa/tCa ratios. There was also a significant inverse linear relationship between the tCa/phos ratio and PTH. These findings are consistent with known domestic avian calcium physiology, and they provide a base of reference for clinical calcium physiology in psittacines. This study also establishes reference values for iCa, tCa, P, TP, Alb, PTH, and 25[OH]D3 in captive thick-billed parrots.