Holding back the genes: limitations of research into canine behavioural genetics

Development of a modified C-BARQ for evaluating behavior in working dogs

Introduction

Current high demand for effective odor detection dogs calls for the development of reliable methods for measuring performance-related behavioral phenotypes in these highly specialized working animals. The Canine Behavioral Assessment & Research Questionnaire (C-BARQ) is a widely used behavioral assessment tool among working dog organizations with a demonstrated ability to predict success/failure of dogs in training. However, this instrument was developed originally to study the prevalence of behavior problems in the pet dog population, and it therefore lacks the capacity to measure specific behavioral propensities that may also be important predictors of working dog success. The current paper examines the factor structure, internal reliability, and content validity of a modified version of the C-BARQ designed to evaluate four new domains of canine behavior in addition to those encompassed by the original C-BARQ. These domains, labeled Playfulness, Impulsivity, Distractibility, and Basophobia (fear of falling), respectively, describe aspects of canine behavior or temperament which are believed to contribute substantially to working dog performance.

Methods

Exploratory factor analysis (EFA) of owner/handler questionnaire responses based on a sample of 1,117 working odor detection dogs.

Results

A total of 15 factors were extracted by EFA, 10 of which correspond to original C-BARQ factors. The remaining 5 comprise the four new domains- Playfulness, Impulsivity, Distractibility, and Basophobia- as well as a fifth new factor labeled Food focus.

Discussion

The resulting Working Dog Canine Behavioral Assessment & Research Questionnaire (WDC-BARQ) successfully expands the measurement capacities of the original C-BARQ to include dimensions of behavior/temperament of particular relevance to many working dog populations.

Domestic dog lineages reveal genetic drivers of behavioral diversification

Selective breeding of domestic dogs has generated diverse breeds often optimized for performing specialized tasks. Despite the heritability of breed-typical behavioral traits, identification of causal loci has proven challenging due to the complexity of canine population structure. We overcome longstanding difficulties in identifying genetic drivers of canine behavior by developing a framework for understanding relationships between breeds and the behaviors that define them, utilizing genetic data for over 4,000 domestic, semi-feral, and wild canids and behavioral survey data for over 46,000 dogs. We identify ten major canine genetic lineages and their behavioral correlates and show that breed diversification is predominantly driven by non-coding regulatory variation. We determine that lineage-associated genes converge in neurodevelopmental co-expression networks, identifying a sheepdog-associated enrichment for interrelated axon guidance functions. This work presents a scaffold for canine diversification that positions the domestic dog as an unparalleled system for revealing the genetic origins of behavioral diversity.

Case Distribution, Sources, and Breeds of Dogs Presenting to a Veterinary Behavior Clinic in the United States from 1997 to 2017

The purpose of this retrospective case study was to evaluate trends over time in case distribution, sources, and breeds of dogs presenting to the behavioral medicine service at a veterinary college referral hospital in the United States. For case distribution and sources, the available records from the behavior service (n = 1923) from 1997 to 2017 were evaluated. Breeds of dogs presenting to all services (n = 51,052) were compared to behavior cases (n = 822) from 2007 to 2016. Over twenty years, 72.2% of dogs presented for aggression, 20.1% for anxieties/fears/phobias, and 7.4% for miscellaneous behavioral problems. Dogs acquired from breeders decreased and dogs from shelters, rescues, or adopted as a stray increased over twenty years (p < 0.0001). The Herding (p = 0.0124) and Terrier (p < 0.0001) groups were overrepresented for behavior problems as compared to all other services over ten years. Variations in terminology and diagnostic approach made comparisons with earlier studies difficult, which underscores a need for a more consistent methodology in veterinary behavioral medicine. Understanding trends in sources of dogs could direct resources aimed at guiding owners when acquiring a pet dog and preventing behavioral problems. Findings related to breeds could help guide research focused on the genetic contributions to behavior.

Active and social life is associated with lower non-social fearfulness in pet dogs

Behavioural problems are leading welfare issues in domestic dogs. In particular, anxiety-related behavioural problems, such as fearfulness and noise sensitivity are highly prevalent conditions that cause distress to fearful dogs. To better understand the environmental factors associated with non-social fear, including noise sensitivity, fear of novel situations, and fear of surfaces and heights, a large online survey including data on 13,700 Finnish pet dogs was performed by the dog owners. After fulfilling inclusion criteria, this data consisted of 9,613 dogs with fear of fireworks, 9,513 dogs with fear of thunder, 6,945 dogs with fear of novel situations, and 2,932 dogs with fear of surfaces and heights. Logistic regression analyses revealed that dogs with frequent non-social fear had experienced less socialisation during puppyhood, were more often neutered, had inexperienced owners, lived without conspecifics, participated less frequently in activities or training, and lived in more urban environments. In addition, we identified several breed differences, and a tendency of more common non-social fear in small dog breeds, which suggests a genetic background. Non-social fearfulness has a negative effect on well-being of the dogs. Our findings suggest that the socialisation and the living environment and the value of other dogs' company and owner interaction via activities and training may improve the well-being of the dogs.

Inadequate socialisation, inactivity, and urban living environment are associated with social fearfulness in pet dogs

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.

Cross-Sectional Age Differences in Canine Personality Traits; Influence of Breed, Sex, Previous Trauma, and Dog Obedience Tasks

The dog has been suggested as a possible model for personality development over the lifespan, however, we know little about how aging may shape their personality or the magnitude of age-related changes. Previously we established that aging influences multiple dog demographics, which could also affect how personality traits change across different age periods. A demographic questionnaire and the Dog Personality Questionnaire were completed for a cross-sectional sample of 1,207 adult dogs living in Hungary (M_age = 7.71, SD = 4.12), split into six different age groups. Results revealed three of the five factors showed significant age effects. Activity/Excitability decreased with age, and whilst Responsiveness to training also decreased, only dogs older than 12 years differed significantly from the other groups. Aggressiveness toward animals showed a quadratic trajectory peaking in dogs aged 6–10 years. The greatest magnitude of age-related change was detected between late senior and geriatric ages, likely caused by compensatory behavioral changes to biological aging and owner attitudes to aging. When the models were re-run including the other explanatory variables, age group was no longer significant for the Responsiveness to training trait. The amount of time spent interacting/playing with the owner partially mediated the relationship between age and this trait, implying that interventions to increase play and training motivation may alleviate the negative effects of aging on dogs' trainability. Fifteen out of 28 explanatory variables were significantly associated with at least one of the five factors [weight, breed (pure/mixed breed), sex, off-leash activity, diet, previous trauma, age of dog when arrived in the household, play, dog training activities, number of known commands and dog obedience tasks]. Similarly to humans, dogs that had previously experienced trauma scored higher in fearfulness and aggression. A higher level of basic obedience was linked to some desirable dog personality traits (lower Fearfulness and Aggression, and higher Activity/Excitability and Responsiveness to training). Regardless of the direction of this relationship, obedience is an important aspect contributing to dog personality questionnaires and the dog-owner relationship. This study is unique in that it considered a wide variety of demographic variables which are influenced by aging.

Highly heritable and functionally relevant breed differences in dog behaviour

Variation across dog breeds presents a unique opportunity to investigate the evolution and biological basis of complex behavioural traits. We integrated behavioural data from more than 14 000 dogs from 101 breeds with breed-averaged genotypic data (n = 5697 dogs) from over 100 000 loci in the dog genome. We found high levels of among-breed heritability for 14 behavioural traits (the proportion of trait variance attributable to genetic similarity among breeds). We next identified 131 single nucleotide polymorphisms associated with breed differences in behaviour, which were found in genes that are highly expressed in the brain and enriched for neurobiological functions and developmental processes, suggesting that they may be functionally associated with behavioural differences. Our results shed light on the heritability and genetic architecture of complex behavioural traits and identify dogs as a powerful model in which to address these questions.

Australian and New Zealand Veterinary Students' Opinions on Animal Welfare and Ethical Issues Concerning Animal Use within Sport, Recreation, and Display

Animals used for sport, recreation and display are highly visible and can divide community attitudes. The study of animal welfare and ethics (AWE) as part of veterinary education is important because it is the responsibility of veterinarians to use their scientific knowledge and skills to promote animal welfare in the context of community expectations. To explore the attitudes of veterinary students in Australia and New Zealand to AWE, a survey of the current cohort was undertaken. The survey aimed to reveal how veterinary students in Australia and New Zealand rate the importance of five selected AWE topics for Day One Competences in animals used in sport, recreation and display and to establish how veterinary students' priorities were associated with gender and stage of study. The response rate (n = 851) across the seven schools was just over 25%. Results indicated little variation on ratings for topics. The topics were ranked in the following order (most to least important): Pushing of animals to their physiologic/behavioral limits; ownership/responsibility; euthanasia; educating the public; and behavior, selection, and training for sport and recreation displays. In contrast to related studies, ratings were not associated with stage of study and there were few differences associated with gender. More females rated the pushing of animals to physiologic/behavioral limits as extremely important than did males ( p < .001). The role of veterinarians in advocating for and educating the public about the welfare of animals used in sport, recreation and display merits further discussion.

Wolf outside, dog inside? The genomic make-up of the Czechoslovakian Wolfdog

BACKGROUND

Genomic methods can provide extraordinary tools to explore the genetic background of wild species and domestic breeds, optimize breeding practices, monitor and limit the spread of recessive diseases, and discourage illegal crossings. In this study we analysed a panel of 170k Single Nucleotide Polymorphisms with a combination of multivariate, Bayesian and outlier gene approaches to examine the genome-wide diversity and inbreeding levels in a recent wolf x dog cross-breed, the Czechoslovakian Wolfdog, which is becoming increasingly popular across Europe.

RESULTS

Pairwise FST values, multivariate and assignment procedures indicated that the Czechoslovakian Wolfdog was significantly differentiated from all the other analysed breeds and also well-distinguished from both parental populations (Carpathian wolves and German Shepherds). Coherently with the low number of founders involved in the breed selection, the individual inbreeding levels calculated from homozygosity regions were relatively high and comparable with those derived from the pedigree data. In contrast, the coefficient of relatedness between individuals estimated from the pedigrees often underestimated the identity-by-descent scores determined using genetic profiles. The timing of the admixture and the effective population size trends estimated from the LD patterns reflected the documented history of the breed. Ancestry reconstruction methods identified more than 300 genes with excess of wolf ancestry compared to random expectations, mainly related to key morphological features, and more than 2000 genes with excess of dog ancestry, playing important roles in lipid metabolism, in the regulation of circadian rhythms, in learning and memory processes, and in sociability, such as the COMT gene, which has been described as a candidate gene for the latter trait in dogs.

CONCLUSIONS

In this study we successfully applied genome-wide procedures to reconstruct the history of the Czechoslovakian Wolfdog, assess individual wolf ancestry proportions and, thanks to the availability of a well-annotated reference genome, identify possible candidate genes for wolf-like and dog-like phenotypic traits typical of this breed, including commonly inherited disorders. Moreover, through the identification of ancestry-informative markers, these genomic approaches could provide tools for forensic applications to unmask illegal crossings with wolves and uncontrolled trades of recent and undeclared wolfdog hybrids.

Defining and Clarifying the Terms Canine Possessive Aggression and Resource Guarding: A Study of Expert Opinion

The terms possessive aggression and resource guarding are often used interchangeably to describe behavior patterns used by a dog to control primary access to a perceived valuable item. The use of inconsistent terminology may impact the effectiveness of communication between dog owners and clinicians, affect treatment and management success for the behavior, and inhibit research progress. The aim of this study was to explore the opinions of canine behavior experts on the meaning of and preference for the terms possessive aggression and resource guarding, as well as to develop and propose an operational ethological definition for the preferential term identified. Eighty-five individuals met the inclusion criteria and were invited to participate in a two-stage online survey. Results from the two-stage survey found that the majority of participants preferred the term resource guarding. Detailed exploration of meaning and definitions required in-depth discussion beyond traditional survey methods, therefore, respondents from the second stage of the survey were invited to participate in an online discussion board. Following content analysis of the data from the discussion board, we conclude that the majority of participants preferred the term resource guarding. Considering 100% consensus was not reached regarding terminology among experts in the field, future authors and clinicians should provide clear definitions where terms are applied to ensure effective communication between all parties and to ensure consistency in canine behavior research. Based on expert contributions, we define resource guarding as “the use of avoidance, threatening, or aggressive behaviors by a dog to retain control of food or non-food items in the presence of a person or other animal.”

The Genetics of How Dogs Became Our Social Allies

Dogs were domesticated from wolves about 15,000 years ago, and an important selection pressure (intentional or unintentional) has been their ability to communicate and cooperate with people. They show extensive human-directed sociability, which varies within as well as between breeds and is not shared by ancestral wolves. Hence, dogs are potentially ideal models for studying the genetics of social behavior. Here, we review some recent research carried out by us and others on this subject. We present results showing that recent selection of different breed types can be used as a model system for investigating the genetic architecture of personalities. Furthermore, we review data showing that human-directed social behavior is significantly related to a small number of genes that have known connections to human social disorders such as autism and schizophrenia. We suggest that dogs are excellent study subjects for analyzing the evolution and genetics of social behavior and can serve as probes for human health and welfare.

Associations between Domestic-Dog Morphology and Behaviour Scores in the Dog Mentality Assessment

The domestic dog shows a wide range of morphologies, that humans have selected for in the process of creating unique breeds. Recent studies have revealed correlations between changes in morphology and behaviour as reported by owners. For example, as height and weight decrease, many undesirable behaviours (non-social fear, hyperactivity and attention seeking) become more apparent. The current study aimed to explore more of these correlations, but this time used reports from trained observers. Phenotypic measurements were recorded from a range of common dog breeds (n = 45) and included cephalic index (CI: the ratio of skull width to skull length), bodyweight, height and sex. These data were then correlated with results from the Dog Mentality Assessment (DMA), which involves trained observers scoring a dog’s reaction to stimuli presented over 10 standardised subtests. Each subtest is designed to evoke a behavioural response. Backward elimination and weighted step-wise regression revealed that shorter dogs demonstrated more aggressive tendencies, reacting defensively toward both assistants dressed as ghosts (p = 0.045), and to a dummy (p = 0.008). Taller dogs were more affectionate when greeting and being handled by humans (p = 0.007, p = <0.001, respectively). Taller dogs were also more cooperative (p = <0.001), and playful (p = 0.001) with humans than shorter dogs. Heavier dogs were more inquisitive toward a dummy (p = 0.011), to the source of a metallic noise (p = 0.010) and to an assistant (p = 0.003). Heavier dogs were also more attentive to the ghosts (p = 0.013). In comparison, lighter dogs were cautious of a dummy (p = <0.001) and fearful of the sound of a gunshot (p = <0.001). Lighter dogs were also cautious of, and demonstrated prolonged fearfulness toward, the source of metallic noise (p = <0.001, p = <0.034, respectively). With a far larger sample and the advantage of third-party reporting (which overcomes potential owner bias), the current findings build on previous studies in this field, further supporting covariance between morphology and behaviour.

Strong selection for behavioural resilience in Australian stock working dogs identified by selective sweep analysis

Background

Working dog handlers and breeders have strong opinions on characteristics that are desirable in the breeds that they use to handle stock. Most of these characteristics are related to conformation or behaviour. This study explored whether the genetics underlying desirable working behaviour traits might be identified by selective sweep analysis; a method that identifies long regions of strong homozygosity combined with allelic divergence from a comparison group. For this analysis, we compared genomic haplotype architecture in two breeds derived from common founder stock but subjected to divergent selective pressures. The breeds studied were the Australian Kelpie, which is registered with the Australian National Kennel Council, and the Australian Working Kelpie, which is registered with the Working Kelpie Council.

Results

A selective sweep spanning 3 megabases on chromosome 3 was identified in the Australian Working Kelpie. This region is the location of genes related to fear-memory formation and pain perception.

Selective sweep loci of similar magnitude were observed in the Australian Kelpie. On chromosome 8 is a locus which may be related to behavioural excitability and on chromosome 30 is a smaller locus which most likely is related to morphology.

Conclusions

Active working stock dogs of the Australian Working Kelpie breed have been bred primarily for gene loci influencing pain perception and fear memory formation. By contrast Australian Kelpies are commonly maintained in urban environments where these characteristics are not required and have been affected by selection for conformation and coat colour. The identified loci may aid in the identification of superior working dogs.

Electronic supplementary material

The online version of this article (doi:10.1186/s40575-015-0017-6) contains supplementary material, which is available to authorized users.

The advent of canine performance science: offering a sustainable future for working dogs

Working and sporting dogs provide an essential contribution to many industries worldwide. The common development, maintenance and disposal of working and sporting dogs can be considered in the same way as other animal production systems. The process of 'production' involves genetic selection, puppy rearing, recruitment and assessment, training, housing and handling, handler education, health and working life end-point management. At present, inefficiencies throughout the production process result in a high failure rate of dogs attaining operational status. This level of wastage would be condemned in other animal production industries for economic reasons and has significant implications for dog welfare, as well as public perceptions of dog-based industries. Standards of acceptable animal use are changing and some historically common uses of animals are no longer publicly acceptable, especially where harm is caused for purposes deemed trivial, or where alternatives exist. Public scrutiny of animal use appears likely to increase and extend to all roles of animals, including working and sporting dogs. Production system processes therefore need to be transparent, traceable and ethically acceptable for animal use to be sustainable into the future. Evidence-based approaches already inform best practice in fields as diverse as agriculture and human athletic performance. This article introduces the nascent discipline of canine performance science, which aims to facilitate optimal product quality and production efficiency, while also assuring evidence-based increments in dog welfare through a process of research and development. Our thesis is that the model of canine performance science offers an objective, transparent and traceable opportunity for industry development in line with community expectations and underpins a sustainable future for working dogs. This article is part of a Special Issue entitled: Canine Behavior.