Mass screening of Irish wolfhound puppies for portosystemic shunts by the dynamic bile acid test

Five hundred and sixty-six Irish wolf hound puppies aged six to 15 weeks were tested for congenital portosystemic shunts by the dynamic bile acid method. Plasma ammonia concentration was also measured in 165 of the puppies both fasting and postprandially. Nineteen puppies (3.4 per cent), nine males and 10 females, had portosystemic shunts. Smaller litters appeared to be more likely to contain affected puppies. The postprandial bile acid concentration was a reliable predictor of the presence of a shunt, with the highest concentration in a normal puppy being 38 mu mol/litre and the lowest in an affected puppy being 43 mu mol/litre. In contrast, fasting bile acid concentrations were normal in the majority of the affected puppies. There was considerable overlap in fasting plasma ammonia concentrations between normal and affected puppies (26 puppies, 15.8 per cent of those tested). Postprandial ammonia concentration appeared to give better separation between the two groups, apart from two individuals which produced bizarre results. It was concluded that the postprandial or dynamic bile acid test is an appropriate test for the mass screening of Irish wolf hound puppies for portosystemic shunts, and guidelines are proposed for the interpretation and follow-up of the test.