RESUMEN
Fifteen greyhounds with tonsillar enlargement were subjected to detailed investigation. Affected greyhounds exhibited coughing, poor racing performance and tonsillar lymphoid hyperplasia over a period of months. Each of the 15 affected animals had evidence of respiratory tract disease. Twelve had non-specific respiratory tract disease, two had pneumonia and one had pulmonary infiltration with eosinophils (PIE). Histopathological examination of the tonsils from affected dogs revealed that greyhounds with tonsillar enlargement are more likely to have tonsillar lymphoid hyperplasia than tonsillitis. As a result, lymphoid hyperplasia would be a suitable term to describe this tonsillar condition. Respiratory tract diseases, rather than tonsillar hyperplasia, was the more likely cause of the poor racing performance of affected dogs. The aetiological relationship, if any, between respiratory disease and tonsillar enlargement is unclear from this study and requires further investigation.