A novel task of canine olfaction for use in adult and senior pet dogs

Abstract

While much work has been done in the field of canine olfaction, there has been little exploration of hyposmia or anosmia. This is partly due to difficulties in reducing confounds like training history and environmental distraction. The current study describes a novel olfaction test using spontaneous search behavior in dogs to find a hidden food treat in a three-choice task with both light-phase and dark-phase conditions. The study was performed in 18 adult control dogs, 18 senior/geriatric dogs enrolled in a longitudinal aging study, and a single dog with severe nasal pathology. In the senior/geriatric and control groups, dogs performed with higher accuracy (p < 0.0001) and were less likely to show biased selection strategy (p < 0.01) in the dark-phase than light-phase. While senior/geriatric dogs performed above chance, they had lower accuracy in the dark-phase compared to controls (p = 0.036). Dogs who scored higher on an owner questionnaire of cognitive decline showed a positive correlation with performance in the dark-phase; performance on additional cognitive tests did not correlate with performance in the dark-phase. This task can be used to quantify canine olfaction using clearly defined endpoints and spontaneous behaviors thus making it feasible to compare between and within groups of pet dogs.

Success in the Natural Detection Task is influenced by only a few factors generally believed to affect dogs’ olfactory performance

“…We found that young adult dogs (2-3 years old) performed the best, while younger and especially older dogs were less successful, which is in contrast to some previous findings showing no effect of age in olfactory tasks on smaller samples [33][34][35][36] . It should be noted that our age groups may not perfectly align with all breeds, but correspond with the general lifespan status of the dogs 50 .…”

“…These changes likely decrease the olfactory ability of dogs. Based on the owners' perception, age-related decline in dogs' olfactory ability was reported 32 , although many studies have not found any age effect in olfactory tasks (companion dogs [33][34][35][36] ; working dogs 7,37 ), which might be explained by the different age range of the samples.…”

Subjective vision assessment in companion dogs using dogVLQ demonstrates age-associated visual dysfunction

“…Our research suggests that older dogs have difficulty using vision to navigate their environments when lighting is very limited. Because it is possible that olfaction ( 45 ) and hearing ( 46 ) are also impaired in older dogs, very low lighting conditions may be particularly difficult for older dogs to navigate in unfamiliar circumstances due to multisensory deficits limiting the ability of a dog to “switch” from one sense to another. Multisensory deficits contribute to an increase in abnormal behavior traits in dogs ( 47 ), namely increased tendency toward obsessive compulsive behaviors and reduced communication with owners.…”