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.Problematic behaviours can be a threat to dog welfare. Anxious dogs may be more vulnerable to diseases and show decreased lifespan 1 . Satisfaction with the dog's behaviour may increase attachment to the dog 2 and problematic behaviours, especially aggressiveness, destructiveness, fearfulness and hyperactivity are a common reason for relinquishment to shelters 3,4 . Problematic behaviours can even lead to euthanasia at a young age 5,6 . Behaviour problems, especially aggressiveness, may be public health concerns 7 . Some of these behaviour problems have been suggested to be analogous, or possibly even homologous to human anxiety disorders 8 , and the study of these spontaneous behaviour problems arising in a shared environment with people may reveal important biological factors underlying many psychiatric conditions. For example, canine compulsive disorder resembles human OCD on both phenotypic and neurochemical level 8 .Behaviour problems are common in our companion canines 9 . The most common reported behaviour problems include excessive barking, inappropriate elimination, destructiveness, aggression and fearfulness 6,10-13 . The prevalence of noise sensitivity in previous studies has varied between 20% and 50% [14][15][16][17][18] . Around 20-25% of dogs show fearfulness of strangers, dogs or situations 15,16 and separation anxiety occurs in 14-20% of dogs 15,16,19 . Furthermore, comorbidity between noise sensitivity and separation anxiety has also been observed 15,20 .Behaviour has a major genetic component [21][22][23][24][25][26][27] and many traits are both phenotypically and genetically correlated 22 . For examp...

problematic behaviours are severe welfare issues for one of the world's most popular pets, the domestic dog. one of the most prevalent behavioural problem that causes distress to dogs is social fearfulness, meaning fear of conspecifics or unfamiliar people. To identify demographic and environmental factors associated with fear of dogs and strangers, logistic regression was utilised with a large dataset of 6,000 pet dogs collected through an owner-filled behavioural survey. Social fearfulness was associated with several factors, including urban environment, poor socialisation during puppyhood, infrequent participation in training and other activities, small body size, female sex, and neutering. in addition, we identified several breed differences, suggesting a genetic contribution to social fearfulness. These findings highlight the role of inadequate socialisation, inactivity, and urban living environmental in fear-related behavioural problems in dogs. Improvements in the management and breeding practices of dogs could, therefore, enhance the welfare of man's best friend. open Scientific RepoRtS | (2020) 10:3527 | https://doi.org/10.1038/s41598-020-60546-w www.nature.com/scientificreports www.nature.com/scientificreports/ ResultsStudy cohort and demographics. We studied the demographic and environmental factors associated with fear of dogs and fear of strangers in datasets of 5,973 and 5,932 dogs, respectively. In the 'fear of dogs' data, the numbers of non-fearful and fearful dogs were 4,806 and 1,167, respectively. The age of the dogs in this dataset varied from 2 months to 17 years (mean age 4.6 years). In the 'fear of strangers' data, the numbers of non-fearful and fearful dogs were 5,036 and 896, respectively. The age of the dogs in this dataset varied from 2 months to 17 years (mean age 4.7 years). 51% of the dogs were females in both datasets. More detailed demographics and the lists of included breeds and the number of individuals per breed are presented in the Supplementary Table S1.

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