Megaesophagus, a chronic dilation of the esophagus in conjunction with a lack of normal tone or strength, appears to occur at an atypically high rate in Friesian horses, according to a report in the proceedings from the 10th International Congress of the World Equine Veterinary Association. The report authors suggested that this might be considered a hereditary problem in the breed.
Researchers identified an apparent increase in the diagnosis of megaesophagus between July 2002 and July 2007 in Friesian horses in The Netherlands. Siebren Boerma, DVM, Spec. Equine Internal Medicine, and Marianne Sloet van Oldruitenborgh-Oosterbaan, DVM, PhD, Dipl ECEIM, Specialist KNMvD Equine Internal Medicine, from the department of equine sciences at Utrecht University, relayed the research results.
Boerma and Oldruitenborgh-Oosterbaan recorded 45 cases of megaesophagus at the Garyp private practice and Utrecht University large animal clinic during the study period (2002-2007). Of these patients, 41 were Friesians. The researchers also noted a familial predisposition among affected horses, suggesting the condition might be hereditary.
Clinical signs of megaesophagus include loss of appetite, muscle wasting, salivation, and mild colic. Further, horses with megaesophagus are prone to esophageal obstruction (choke).
Management of affected horses can be costly, challenging, and can be associated with serious medical complications such as aspiration pneumonia (pneumonia caused by inhaling foreign objects into the lungs).