Investigation of high gamma‐glutamyltransferase syndrome in California Thoroughbred racehorses

Abstract Background Increases in serum gamma‐glutamyltransferase (GGT) activity have been reported in Thoroughbred (TB) racehorses and associated with maladaptation to training but the underlying etiology remains unknown. Hypothesis/Objectives Classify the etiology of high GGT syndrome in racing TBs by assessment of pancreatic enzymes, vitamin E concentrations, and both a candidate gene and whole genome association study. We hypothesized that a genetic variant resulting in antioxidant insufficiency or pancreatic dysfunction would be responsible for high GGT syndrome in TBs. Animals A total of 138 California racing TBs. Amylase: n = 31 affected (serum GGT activity ≥60 IU/L), n = 52 control (serum GGT activity