EVALUATION OF VITAMIN-D STATUS OF LLAMAS AND ALPACAS WITH HYPOPHOSPHATEMIC RICKETS

Objective - To evaluate vitamin D concentrations in juvenile llamas an d alpacas with hypophosphatemic rickets. Design - Prospective cohort s tudy. Animals - 21 llamas (14 with rickets, 7 clinically normal) and 9 alpacas (6 with rickets, 3 clinically normal). Procedures - Blood sam ples were collected al the time of diagnosis and prior to the initiati on of treatment. Serum concentrations of calcium, inorganic phosphorus , and 25-hydroxycholecalciferol (vitamin D-3) were determined on ail s amples. Comparisons were completed for disease status, age, sex, speci es, month of birth, and ail interactions. Results - Serum concentratio ns of phosphorus and vitamin D were lower in affected llamas and alpac as than in clinically normal llamas and alpacas, even when mean concen trations were adjusted for age differences. Species (llama or alpaca), sex, and age did not affect any of the metabolite concentrations with in this study population. Month of birth influenced vitamin D concentr ations and number of affected llamas and alpacas per month. The greate st number of affected llamas and alpacas was identified between Januar y through March, suggesting a seasonal pattern to this syndrome. Treat ment of affected llamas and alpacas with vitamin D resulted in increas ed concentrations oi phosphorus and vitamin D. Serum phosphorus concen tration was best predicted by 2 independent variables (serum vitamin D concentration and month of birth). Clinical Implications - We believe vitamin D deficiency is the primacy cause of hypophosphatemic-rickets of growing camelids, and the observed hypophosphatemia is secondary P o a primary deficiency of vitamin D. Appropriate treatment with vitami n D supplements can correct hypophosphatemia and vitamin D deficiency in camelids.