Heritability of behavioural traits in domestic dogs: A meta-analysis

Genetic dissection of behavioral traits related to successful training of drug detection dogs

Drug detection dogs play integral roles in society. However, the interplay between their behaviors and genetic characteristics underlying their performance remains uninvestigated. Herein, more than 120,000 genetic variants were evaluated in 326 German Shepherd or Labrador Retriever dogs to profile the genetic traits associated with various behavioral traits related to the successful training of drug detection dogs. Behavioral breed differences were observed in 'friendliness to humans' and 'tolerance to dogs.' A genome-wide association study within both breeds identified 11 regions potentially associated with drug detection dog characteristics as well as 'interest in the target' and 'friendliness to humans,' which are related to drug detection abilities. Among them, 63 protein-coding genes, including Atat1 and Pfn2 known to be associated with anxiety-related or exploration behavior in mice, respectively, were located surrounding the identified candidate polymorphisms. This study highlights genetic characteristics associated with behavioral traits that are important for the successful training of drug detection dogs. Thus, these findings may facilitate improved breeding and training of these dogs.

Prevalence, comorbidity, and breed differences in canine anxiety in 13,700 Finnish pet dogs

Behaviour problems and anxieties in dogs decrease their quality of life and may lead to relinquishment or euthanasia. Considering the large number of pet dogs and the commonness of these problematic behaviours, a better understanding of the epidemiology and related molecular and environmental factors is needed. We have here studied the prevalence, comorbidity, and breed specificity of seven canine anxiety-like traits: noise sensitivity, fearfulness, fear of surfaces and heights, inattention/impulsivity, compulsion, separation related behaviour and aggression with an online behaviour questionnaire answered by dog owners. Our results show that noise sensitivity is the most common anxiety-related trait with a prevalence of 32% in 13,700 Finnish pet dogs. Due to the high prevalence of noise sensitivity and fear, they were the most common comorbidities. However, when comparing the relative risk, the largest risk ratios were seen between hyperactivity/inattention, separation related behaviour and compulsion, and between fear and aggression. Furthermore, dog breeds showed large differences in prevalence of all anxiety-related traits, suggesting a strong genetic contribution. As a result, selective breeding focusing on behaviour may reduce the prevalence of canine anxieties. Anxious animals may suffer from chronic stress and thus, modified breeding policies could improve the welfare of our companion dogs.

Reduced heart rate variability in pet dogs affected by anxiety-related behaviour problems

We present here the first evidence of correlation between canine anxiety-related behavioural problems and heart rate variability (HRV). HRV is known to be related to a range of mental disorders in humans; however this has not been explored in dogs. Behavioural problems in dogs can result in suffering, property destruction and human injury. Dog behaviour problems were assessed by owner questionnaire and the extreme high and low scoring dogs were recruited into either affected (n=10) or unaffected (n=20) groups. HRV was assessed in dogs at their homes, while being held in lateral recumbency for 5min using manual restraint. Salivary cortisol samples were taken before and after HRV testing. Dogs were assessed as either being reactive to the procedure (barking, growling, struggling or shaking) or unreactive. There was no effect of reactivity or behaviour problems on salivary cortisol levels at baseline or in response to the treatment. There was a significant effect of reactivity on HR (F_1,26=5.54; P=0.026), and no effect of behaviour problems (F_1,26=1.07; P=0.311). There was no effect of reactivity on any of the HRV measures. The presence of behaviour problems had a significant effect on a range of measures of HRV, with unaffected dogs having higher standard deviation of RR intervals (F_1,26=6.39; P=0.018), higher high frequency spectrum (F_1,26=5.23; P=0.031) and higher low frequency spectrum (F_1,26=9.25; P=0.005) power. There was no effect of behaviour problems on very low frequency spectrum power (F_1,26=1.40; P=0.248). Together these results provide evidence for a fundamental physiological difference between dogs affected or unaffected with behaviour problems. This study provides evidence for further investigation into the role of HRV in the pathophysiology of canine anxiety-related behaviour problems.