Endoscopic and Virological Observations on Respiratory Disease in a Group of Young Thoroughbred Horses in Training

Burrell, Michael Howard (1985) Endoscopic and Virological Observations on Respiratory Disease in a Group of Young Thoroughbred Horses in Training. MVM(R) thesis, University of Glasgow.

Abstract

A group of racehorses in a commercial training stable were examined on several occasions with a fibreoptic endoscope and monitored for evidence of clinical respiratory disease, viral infection and performance in races. Three conditions which have become easily recognisable by endoscopy were assessed at each examination: Pharyngeal lymphoid hyperplasia (PLH), exercise induced pulmonary haemorrhage (EIPH) and intratracheal mucoid exudate or mucopus. There was only one case of possible clinical respiratory disease and in general the horses were performing to the trainers satisfaction with placings in 50 per cent of starts. Only equine herpes virus-2 (EHV-2) infection was detected by virus isolation from nasopharyngeal swabs and no serological evidence of viral infections were noted. Pharyngeal lymphoid hyperplasia was present to some degree in all horses and its gradual decrease in severity correlated well with increasing age. There was no association between PLH severity and antibody titres to EHV-1, or with the isolation of EHV-2. Finishing position in races was not affected by PLH severity. EIPH was evident on 23 out of 49 (47 per cent) examinations after maximal speed training exercise. The severity of PLH did not have any effect on the incidence of EIPH in this study. Eighteen out of 19 (95 per cent) horses examined on at least two occasions had EIPH but its occurence was not predictable. Observable mucoid or mucopurulent exudate was present in the trachea in 60 out of 118 (50 per cent) examinations and the amount seen was increased following exercise. The large amounts of mucus are interpreted as resulting from lower respiratory tract inflammation, suggesting that a degree of airway inflammation is common in racing horses. Airway mucus in the dorsal phayngeal recess was associated with intratracheal exudate and it is postulated that during exercise tracheal mucus can become shifted by the airflow to eventually impinge on the tonsillar tissue of the dorsal pharyngeal recess.

• Item Type: Thesis (MVM(R))
• Qualification Level: Masters
• Keywords: Veterinary science
• Date of Award: 1985
• Depositing User: Enlighten Team
• Unique ID: glathesis:1985-77370
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 14 Jan 2020 11:53
• Last Modified: 14 Jan 2020 11:53
• URI: https://theses.gla.ac.uk/id/eprint/77370