Evaluation of the Submaximal Treadmill-Based Fitness Test in Six Brachycephalic Breeds—A Follow-Up Study

SIMPLE SUMMARY: The application of a standardised submaximal fitness test on a treadmill has shown promising feasibility and efficacy in identifying clinical signs of brachycephalic obstructive airway syndrome in Pugs. Although early diagnosis of this disease is necessary and exercise testing combined with functional assessment has been shown to be useful, there is no evaluation of the different brachycephalic breeds. In this study, 79 dogs of different brachycephalic breeds were included to complete the fitness test under standardised conditions. Most of the examined dogs quickly adapted to running on a treadmill, so they were well monitored and consistently exercised during the test. The trotting speed can be adjusted individually, so the test also showed good applicability with other breeds. The breathing noises that occurred partially worsened over time, and some dogs only showed clinical signs of being affected until the test duration progressed. Thus, this fitness test opens the possibility of identifying affected dogs of other breeds, even if the clinical signs are only shown under exercise. ABSTRACT: Brachycephalic obstructive airway syndrome (BOAS) in dogs challenges veterinary surgeons both with a complex clinical picture as well as wide-ranging ways to diagnose the disease, often not easily implemented nor standardised in clinical practice. The assessment of a combination of exercise testing, the occurrence of breathing noises, recovery time, and respiratory effort proved to be an appropriate method to identify Pugs with BOAS. The purpose of this study was to apply an established standardised, submaximal, treadmill-based fitness test for Pugs to other brachycephalic dog breeds. A total of 79 participants, belonging to 6 different brachycephalic breeds, trotted 15 min with an individual comfort speed of 3–7 km/h on a treadmill. Additionally, functional BOAS grading based on respiratory clinical signs before and after exercise was applied. The test was passed if the dogs presented with a BOAS grade of 0 or 1 and their vital parameters recovered to baseline within 15 min after exercise. A total of 68% showed a BOAS grade of 0 or 1 and passed the fitness test. Of the failed participants, 65% failed due to BOAS affectedness, 9% were categorised as not affected by BOAS and failed due to not passing the fitness test only, and 26% showed both failure criteria. The fitness test can be a useful method to identify BOAS-affected dogs in other brachycephalic breeds and to diagnose BOAS in dogs that only show clinical signs under exercise.