Effect of a Collar and Harness on Intraocular Pressure and Respiration Rate of Brachycephalic and Dolichocephalic Dogs

Background: Dogs are a popular pet in many countries, and for them to gain appropriate exercise, many owners opt to walk them on a leash. Despite health and welfare concerns, brachycephalic breeds remain common as pets, with limited research existing that investigates the best restraint type for these animals. Objectives: This study aimed to test the effect of a collar and harness during stationary and exercise conditions on the intra‐ocular pressure (IOP) and respiration rate (RR) of brachycephalic and dolichocephalic dogs. Methods: A total of 24 healthy dogs, both brachycephalic and dolichocephalic, were recruited for the study and underwent stationary and exercise conditions in two restraint types in a within‐between‐subjects design. IOP was measured by rebound tonometry, and RR was measured using clinical and visual methods by the same experimenter. Results: Just wearing a collar in a stationary condition increased IOP in brachycephalic dogs (p < 0.05) but not in dolichocephalic dogs (p > 0.05). Exercising in a collar increased IOP for both groups of dogs (p < 0.05), whereas exercising in a harness did not affect IOP for either group (p > 0.05). RR increased in exercise conditions for both restraint types in brachycephalic dogs (p < 0.05), with no difference between collar and harness (p > 0.05). Conclusions: Data suggest that collars may elevate IOP during exercise for all dogs and also during stationary conditions for brachycephalic breeds. Owners need to be conscious of the most appropriate restraint for their dog to avoid deleterious effects on IOP and RR.