Pharyngeal lymphoid hyperplasia in Thoroughbred racehorses in training.
The prevalence of pharyngeal lymphoid hyperplasia in Thoroughbred racehorses in training was investigated using a fibre optic endoscope. Of the 70 horses examined, all but 8 showed evidence of pharyngeal lymphoid hyperplasia and the severity of the pharyngeal changes decreased with age. Two-year old horses had greater pharyngeal lymphoid hyperplasia (p less than 0.05) when compared to all other age groups. More horses (p less than 0.05) with Grade 3 or Grade 4 pharyngeal lymphoid hyperplasia experienced recent mild respiratory disease than did horses with Grade 2 or less pharyngeal lymphoid hyperplasia. None of the horses examined had a history of diminished racing performance although 30% had either Grade 3 or Grade 4 pharyngeal lymphoid hyperplasia.
D000367:Age Factors; D000818:Animals; D003371:Cough / Q000662:veterinary; D004724:Endoscopy / Q000662:veterinary; D005260:Female; D006734:Horse Diseases / Q000473:pathology*; D006736:Horses; D006965:Hyperplasia; D008221:Lymphoid Tissue / Q000473:pathology*; D008297:Male; D010612:Pharyngitis / Q000473:pathology / Q000662:veterinary*; D012220:Rhinitis / Q000662:veterinary; D012420:Running