Impact of facial conformation on canine health: Brachycephalic Obstructive Airway Syndrome

The domestic dog may be the most morphologically diverse terrestrial mammalian species known to man; pedigree dogs are artificially selected for extreme aesthetics dictated by formal Breed Standards, and breed-related disorders linked to conformation are ubiquitous and diverse. Brachycephaly–foreshortening of the facial skeleton–is a discrete mutation that has been selected for in many popular dog breeds e.g. the Bulldog, Pug, and French Bulldog. A chronic, debilitating respiratory syndrome, whereby soft tissue blocks the airways, predominantly affects dogs with this conformation, and thus is labelled Brachycephalic Obstructive Airway Syndrome (BOAS). Despite the name of the syndrome, scientific evidence quantitatively linking brachycephaly with BOAS is lacking, but it could aid efforts to select for healthier conformations. Here we show, in (1) an exploratory study of 700 dogs of diverse breeds and conformations, and (2) a confirmatory study of 154 brachycephalic dogs, that BOAS risk increases sharply in a non-linear manner as relative muzzle length shortens. BOAS only occurred in dogs whose muzzles comprised less than half their cranial lengths. Thicker neck girths also increased BOAS risk in both populations: a risk factor for human sleep apnoea and not previously realised in dogs; and obesity was found to further increase BOAS risk. This study provides evidence that breeding for brachycephaly leads to an increased risk of BOAS in dogs, with risk increasing as the morphology becomes more exaggerated. As such, dog breeders and buyers should be aware of this risk when selecting dogs, and breeding organisations should actively discourage exaggeration of this high-risk conformation in breed standards and the show ring

Journal of the American Veterinary Medical Association 193 7 850 853 UNITED STATES

Chronic constipation, nonresponsive to medical management and associated with idiopathic megacolon, was diagnosed in 38 cats from 1979 to 1985. All cats were treated by subtotal colectomy and enterocolostomy, in which the ileum or distal portion of the jejunum was joined to a 2- to 4-cm segment of distal portion of the colon preserved to accommodate an end-to-end anastomosis. After surgery, cats usually were depressed and anorectic, had tenesmus, and passed liquid tarry feces. In 37 cats 1 week to 3 months after surgery, character of the feces changed from diarrhea to soft semiformed or formed feces. One cat had severe diarrhea that was nonresponsive to diet change and pharmacologic treatment; the diarrhea resolved after 4.5 months. One cat developed a stricture of the enterocolostomy, which was relieved by 3 balloon catheter dilatations. All cats regained normal appetite, did not lose weight, and were not incontinent. Three cats had sporadic episodes of constipation and were easily treated. Results of histologic examination of the resected portion of colon in 23 cats were inconclusive