Staff veterinarian and PhD student University of California, Davis Davis, CA, United States
Abstract:
Background: There is little reported about the association among parathyroid hormone (PTH), urinary fractional excretion of phosphorus (FeP), and serum calcium (sCa2+) with clinical signs in horses with nutritional secondary hyperparathyroidism (NSH).
Objectives: To determine the association between concentrations of PTH and sCa2+, as well as FeP, in horses with clinical and subclinical NSH. Animals: 116 horses in Colombia tested for NSH. Horses were assigned to three groups: 1) increased PTH + clinical signs (n=61); 2) increased PTH and no clinical signs (n=25); 3) PTH within the reference range (controls; n=30).
Methods: Retrospective case-control study. Only horses >2 years of age were included. Clinical horses had facial bone deformation or lameness. Pair-wise comparisons (for PTH; subclinical vs clinical) were done with a Mann Whitney test. Three-group comparisons were done with Kruskal-Wallis and Dunn’s multiple comparison tests.
Results: The median age was 7.62 (2-17) years. 83% of horses were female. Paso Finos were the most common breed (56%). PTH was significantly increased in clinical horses (223.9 pg/mL [67.55–1451.00]) compared to subclinical (117.1 pg/mL [65.50–523.00];P <0.0001). Conclusions and clinical importance: Horses with clinical NSH had higher PTH concentrations than horses with subclinical NSH. Horses with NSH had higher FeP as compared to horses with normal PTH. Clinical horses had lower sCa2+ than controls.
