Dog-directed Aggression Research Articles

Deciphering the genetic basis of behavioral traits in dogs: Observed-trait GWAS and latent-trait GWAS analysis reveal key genes and variants

Dogs exhibit remarkable phenotypic diversity, particularly in behavioral traits, making them an excellent model for studying the genetic basis of complex behaviors. Behavioral traits such as aggression and fear are highly heritable among different dog breeds, but their genetic basis is largely unknown. We used the genome-wide association study (GWAS) to identify candidate genes associated with nine behavioral traits including; stranger-directed aggression (SDA), owner-directed aggression (ODA), dog-directed aggression (DDA), stranger-directed fear (SDF), nonsocial fear (NF), dog-directed fear (DDF), touch sensitivity (TS), separation-related behavior (SRB) and attachment attention-seeking (AAS). The observed behavioral traits were collected from 38,714 to 40,460 individuals across 108 modern dog breeds. We performed a GWAS based on a latent trait extracted using the confirmatory factor analysis (CFA) method with nine observable behavioral traits and compared the results with those from the GWAS of the observed traits. Using both observed-trait and latent-trait GWAS, we identified 41 significant SNPs that were common between both GWAS methods, of which 26 were pleiotropic, as well as 10 SNPs unique to the latent-trait GWAS, and 5 SNPs unique to the observed-trait GWAS discovered. These SNPs were associated with 21 genes in latent-trait GWAS and 22 genes in the observed-trait GWAS, with 19 genes shared by both. According to previous studies, some of the genes from this study have been reported to be related to behavioral and neurological functions in dogs. In the human population, these identified genes play a role in either the formation of the nervous system or are linked to various mental health conditions. Taken together, our findings suggest that latent-trait GWAS for behavioral traits in dogs identifies significant latent genes that are neurologically prioritized.

Correlation between aggression at the veterinary clinic and problem behaviors at home for cats in the USA.

The aim of the study was to determine whether cats that exhibit aggression during veterinary visits are more likely to have behavior problems at home. An online, anonymous, cross-sectional survey was developed and distributed to residents in the USA who were aged over 18 years and who were the primary owners of at least one cat. The survey collected information about cat and household factors, and utilized a validated questionnaire instrument for obtaining behavioral information of pet cats. Aggression at the veterinary clinic was reported in 42.6% of the cats. The frequency of aggression exhibited at the veterinary clinic was lower in cats that lived in multi-cat households. Most cats did not receive medications intended to reduce fear, anxiety and/or pain before veterinary visits. Aggression at the veterinary clinic was positively associated with behavior problems at home, including stranger-directed aggression, owner-directed aggression, resistance to restraint, familiar cat aggression, dog-directed aggression, house-soiling, separation-related behaviors and scratching claws on inappropriate surfaces indoors. Cats that exhibit aggression at the veterinary clinic are more likely to exhibit aggression and anxiety-related behaviors at home. Veterinarians should screen cats that exhibit aggression at the veterinary clinic for behavior problems at home to institute prompt diagnosis and treatment.

Relationships between demographic characteristics of shelter dogs and performance on tests of a behavioral evaluation and between performance and adoption success

Dog behavior has been studied using diverse methods, including owner-completed questionnaires, records from veterinary clinics that evaluate behavioral problems, and test batteries such as those used by some animal shelters. Measures of prevalence for multiple behavioral issues and analyses of whether dog demographic characteristics are associated with problematic behaviors are commonly reported in studies using questionnaires and clinical records; however, these measures are infrequently reported for all tests and subtests in studies using data from shelter behavioral evaluations. In this study, we determined prevalence of both concerning and dangerous behaviors on 12 tests and subtests of a canine behavioral evaluation by analyzing data collected by the behavioral staff at a NY shelter (n = 1,104 dogs tested between 2014 and 2019). We also examined whether behavior on four tests and subtests with prevalence over 10% (two Sociability subtests, Handling test, and Dog-to-dog meeting subtest) was associated with likelihood of being returned to the shelter post-adoption, and whether dog demographic characteristics (age, sex, reproductive status, and body size) were associated with behaviors on tests and subtests. Of all dogs tested, prevalence measures of dangerous behaviors were always less than 5%. Our measures of prevalence (concerning and dangerous behaviors combined) for food guarding (15.5%), stranger-directed aggression (6.5%), and dog-directed aggression (16.7%) were generally similar to those reported for dogs in other shelters and in homes. For the four tests/subtests examined here, displaying concerning or dangerous behavior was not significantly associated with return to the shelter, and positive predictive values (PPV) were low, which implies that many positive tests will be false positives. We also found few significant associations between demographic characteristics and behavior on tests and subtests and PPV were low. Other factors, such as previous experiences with people and dogs, as well as underlying physiological and neurobiological processes, may be more important influences on a dog’s behavior during a shelter behavioral evaluation than general demographic characteristics. Total number of tests and subtests out of a possible 12 on which dogs were assessed as showing concerning or dangerous behaviors ranged from zero to 7 per dog (median, 0; mean, 0.82). In summary, poor predictive abilities characterized associations between performance on certain tests/subtests of the behavioral evaluation and return to the shelter and between demographic characteristics and behavior on test/subtests. Our data may contribute to the ongoing debate about the usefulness of canine behavioral evaluations in shelters.

Canine Behavioral Assessment and Research Questionnaire (C-BARQ): Validation of the Italian Translation.

The aim of this study is to develop an Italian translation of the 100-item Canine Behavioral Assessment and Research Questionnaire (C-BARQ) version and to validate its psychometric properties, in order to facilitate systematic, large-scale studies on dog behavior for Italian-speaking dog owners. A total number of 803 responses by dog owners were collected online. Using the Principal Axis Method and Common Factor Analysis with Quartimin oblique rotation (p < 0.05), a factorial structure was found including 13 factors composed of 62 items and explaining 53.5% of the total variance. Eight factors showed high reliability (Cronbach's alpha > 0.70), namely: stranger-directed aggression/fear, dog-directed fear, owner-directed aggression, separation-related behavior, chasing, dog-directed aggression, attachment/attention seeking, and elimination problems. Three factors were slightly under the threshold and two had only modest reliability (non-social fear, energy level, touch sensitivity, excitability and trainability). A potential explanation for factors with low reliability is that the composing items do not describe behaviors resulting from homogeneous stimuli or situations. Although our factorial structure resembled in most respects that of the most recently published Canadian version, some important exceptions are present regarding dog rivalry, intraspecific aggression, fear/aggression towards strangers, touch sensitivity and chewing inappropriate objects. Such differences may be due to demographic and/or cultural differences between the sampled populations. Overall, the results suggest that a 62-item Italian C-BARQ can be reliably used in studies on dog behavior.

RETRACTED: Demographic characteristics of shelter dogs predict performance on tests of a behavioral evaluation and overall performance predicts adoption success

Dog behavior has been studied using diverse methods, including owner-completed questionnaires, records from veterinary clinics that evaluate behavioral problems, and test batteries such as those used by some animal shelters. Measures of prevalence for multiple behavioral issues and analyses of whether dog demographic characteristics predict problematic behaviors are commonly reported in studies using questionnaires and clinical records; however, these measures are infrequently reported for all tests and subtests in studies using data from shelter behavioral evaluations. In this study, we determined prevalence of both concerning and dangerous behaviors on 14 tests and subtests of a canine behavioral evaluation by analyzing data collected by the behavioral staff at a NY shelter. Canine evaluations were conducted a few days after intake ( n = 1104 dogs tested between 2014-2019). Our study sample represents all dogs admitted to the shelter except those quickly reclaimed by owners and those euthanized at the request of their owners; rarer exceptions included very undersocialized dogs and dogs assessed at intake as unsafe to make available for adoption. We also examined whether dog demographic characteristics (age, sex, reproductive status, and body size) predicted behaviors on tests and subtests and whether total number of tests/subtests with concerning or dangerous behaviors predicted likelihood of being returned to the shelter postadoption. Of all dogs tested, prevalence measures of dangerous behaviors were always less than 5%. Prevalence of concerning behaviors during the evaluations were usually higher, with the highest being 36% for one of the Sociability subtests, indicating that about one third of dogs tested ignored rather than interacted with the evaluator. Our measures of prevalence for food guarding (15.5%), stranger-directed aggression (6.5%), and dog-directed aggression (16.7%) were generally similar to those reported for dogs in other shelters and in homes. Of the demographic characteristics examined, age class most consistently predicted assessment of concerning or dangerous behaviors on several tests and subtests, with these behaviors typically being most common in seniors, followed by adults, and then juveniles. Finally, we found that for each additional test or subtest on which a dog showed concerning or dangerous behaviors, the odds of being returned to the shelter increased by a factor of 1.22. Our findings may aid shelters in identifying dogs, such as older individuals and those assessed as showing problematic behaviors on several tests and subtests of an evaluation, that would benefit from behavioral plans and special adoption efforts to help them enter and remain in adoptive homes.

Personality traits associate with behavioral problems in pet dogs

Personality traits, especially neuroticism, strongly predict psychopathology. The domestic dog (Canis lupus familiaris Linnaeus, 1758) is used as a natural model for psychiatric disorders, but the similarity between dog and human personality and the association between dog personality and unwanted behavioral traits, such as fearfulness, aggressiveness, and impulsivity/inattention, remain unknown. This study utilized structural equation modeling (SEM) with survey data of 11,360 dogs to examine the associations and correlations between seven personality and ten unwanted behavioral traits. Personality traits included insecurity, energy, training focus, aggressiveness/dominance, human sociability, dog sociability, and perseverance. Unwanted behavioral traits included fearfulness, noise sensitivity, fear of surfaces/heights, separation anxiety, barking, stranger-directed aggression, owner-directed aggression, dog-directed aggression, hyperactivity/impulsivity, and inattention. We first fitted confirmatory factor models for the unwanted behavioral traits and the best model grouped unwanted behaviors into four latent traits: fear-related behavior, fear-aggression, aggression, and impulsivity/inattention and used this structure in the subsequent SEM model. Especially, insecurity, which resembles the human neuroticism trait, was strongly associated with unwanted behavior, paralleling the association between neuroticism and psychopathology. Similarly, training focus, resembling conscientiousness, was negatively related to impulsivity/inattention, and aggressiveness/dominance was associated with aggressive behaviors, resembling associations of conscientiousness and agreeableness with attention deficit hyperactivity disorder and aggression-related psychopathology, respectively. These results indicate that dog personality traits resemble human personality traits, suggesting that their neurological and genetic basis may also be similar and making the dog a suitable animal model for human behavior and psychiatric disorders.

Behavior traits associated with career outcome in a prison puppy-raising program

The Canine Behavioral Assessment and Research Questionnaire (C-BARQ©) (http://www.cbarq.org) has been used to measure behaviors associated with release or graduation from several assistance dog programs, however it has never been evaluated within a prison environment. This study investigated whether a modified version of the C-BARQ© can be utilized in a prison puppy-raising program (Puppies Behind Bars, PBB) to identify behaviors that are associated with dogs’ career outcomes. PBB dogs that successfully complete the program are placed as service dogs or explosives detection dogs (EDD). Dogs are released from the program as a result of behavioral or medical problems. The PBB program has more than one career outcome, facilitating an assessment of the C-BARQ© as a tool to identify specific working dog roles based on differences in C-BARQ© subscale scores. We examined the associations between subscale scores and career outcomes by comparing the scores of dogs with successful outcomes (service or EDD) with those released for behavioral reasons. We assessed the questionnaire’s application to the PBB setting and its ability to distinguish between outcomes. 314 paper copies of the C-BARQ© were completed by puppy raisers from seven correctional facilities in the New York area when their assigned dog was between 6 and 16 months old. Dogs that had successfully completed the PBB program or had been released due to behavioral issues were included, whereas dogs still in training and those released for medical reasons were excluded. A total of 271 completed C-BARQ© questionnaires were analyzed. Service dogs and EDDs were compared with released dogs to determine whether C-BARQ subscale scores were associated with outcome. Multinomial log-linear models containing one subscale score and fixed factors (age group, medical category, sex, neuter status within sex, the interaction between age group and medical category) and outcome as the dependent variable, were fitted for each subscale. Service dogs had lower stranger-directed aggression, owner-directed aggression, dog-directed aggression, dog-directed fear, dog rivalry, chasing, stranger-directed fear, and separation-related problems than released dogs. EDDs had lower trainability, dog-directed fear, dog rivalry, and attachment/attention-seeking behavior than released dogs. These findings suggest that some of the C-BARQ© subscales might be used in the future to predict outcomes for young dogs. Results show that the C-BARQ© can be applied to the PBB program; however, the omission of seven questions is recommended.

Expression of Behavioural Traits in Goldendoodles and Labradoodles.

Simple SummaryCrossbred dogs are gaining in popularity with the general public, but we do not fully understand how these crossbreds behave compared to their parent breeds in regard to inherited behaviour traits. Because of this, we investigated behaviours exhibited by crossbred dogs by focusing on the popular Goldendoodle and Labradoodle crossbreds by comparing them to their corresponding parent or constituent breeds: Standard or Miniature Poodle, and Golden Retriever or Labrador Retriever. The data for this study was provided by 5141 volunteer dog owners from across the world who filled out the Canine Behavioural Assessment and Research Questionnaire (C-BARQ) online survey. The survey results were used to analyse fourteen different representative behavioural trait scores. As expected from a first-generation crossbred (F1), the crossbreds in our study tend to fall between the two parent breeds with some exceptions. The Goldendoodle displayed more problematic behaviour when compared to its constituent breeds, whereas the Labradoodle only differs significantly from the Miniature Poodle in dog rivalry. These results can help advise future dog owners on behavioural trends for particular crossbreds.As crossbred dogs gain in popularity, how they express inherited behaviour traits in comparison to their purebred constituent breeds is of interest. We investigated behaviours exhibited by crossbred dogs by focusing on the popular Goldendoodle and Labradoodle crossbreds and comparing them to their corresponding constituent breeds: Standard and Miniature Poodle, Golden Retriever or Labrador Retriever. The data for this study was provided by 5141 volunteer dog owners who filled out the Canine Behavioural Assessment and Research Questionnaire (C-BARQ) online survey. The survey results were used to analyse breed differences in fourteen representative behavioural trait scores: trainability, stranger-directed aggression, owner-directed aggression, dog-directed aggression, dog rivalry, dog-directed fear, stranger-directed fear, non-social fear, touch sensitivity, separation-related problems, excitability, attachment/attention-seeking behaviours, energy and chasing. As expected from a first-generation crossbred (F1), the crossbreds in our study tend to fall between the two constituent parent breeds with some exceptions. Our results suggest that the F1 Labradoodle differed significantly from one of the pure constituent breeds only in dog rivalry, whereas the F1 Goldendoodle behaviour varied from one or more pure constituent breeds in dog rivalry, dog-directed aggression, dog-directed fear, and stranger-directed fear. These results can help advise future dog owners on behavioural trends for particular crossbreds.

Desexing Dogs: A Review of the Current Literature.

Simple SummaryDesexing is a general term for interventions suppressing fertility in dogs, most commonly by surgically removing the testes or ovaries (“gonadectomy”). Desexing is promoted for population control, health benefits, and behavior modification. Surprisingly, the existing evidence shows no effect of desexing on population size in companion or shelter dogs; however, an effect has been shown for desexing female free-roaming dogs. Desexing has consistently been shown to change various health risks, including a reduction in pyometra and mammary tumor risk, as well as an increased risk of cranial cruciate ligament rupture, several forms of cancer, and obesity in both sexes. Other health effects vary considerably between breeds and sexes. A lifespan advantage in desexed dogs has consistently been shown in females, while the evidence is inconsistent in males, and the effect is smaller in studies that found one. There is more literature on behavioral effects in males than in females, and the evidence suggests reduced libido, roaming, conspecific mounting, and urinary marking in a large percentage of gonadectomized males, and reduced male dog aggression in a majority of males gonadectomized because of behavioral problems. The decision whether to desex dogs needs to be individualized based on the available evidence.Background: Desexing dogs is promoted for population control, preventative healthcare, and behavior modification. Common methods are orchiectomy and ovariectomy/ovariohysterectomy. GnRH superagonist implants are available in some areas. Alternative methods like vasectomy and salpingectomy/hysterectomy are uncommon. The terminology used to describe desexing is inconsistent and contradictory, showing a need for the adaption of standardized terminology. Population Control: Surprisingly, empirical studies show no effects of desexing on population control in companion and shelter dogs despite desexing being consistently recommended in the literature. There is evidence for a population control effect in free-roaming dogs, where desexing also has benefits on zoonotic disease and bite risk. Population control in free-roaming dogs is mostly correlated with female, not male desexing. Health and Lifespan: Desexing affects numerous disease risks, but studies commonly neglect age at diagnosis and overall lifespan, age being by far the most important risk factor for most diseases. We argue that lifespan is a more important outcome than ultimate cause of death. A beneficial effect of desexing on lifespan is consistently demonstrated in females, while evidence for a beneficial effect in males is inconsistent. Studies are likely biased in desexing being a proxy for better care and desexed dogs having already lived to the age of desexing. Desexing reduces or eliminates common life-limiting diseases of the female reproductive system such as pyometra and mammary tumors, while no analogous effect exists in males. Disease risks increases across sexes and breeds include cruciate ligament rupture, various cancers, and obesity. Urinary incontinence risk is increased in females only. Various other disease risk changes show considerable variability between breeds and sexes. Behavioral Effects: Desexed males show reduced libido, roaming, conspecific mounting, and urinary marking frequency, as well as reduced male dog-directed aggression in a majority of males desexed for behavioral reasons. There is a detrimental effect on the risk and progression of age-related cognitive dysfunction. Desexed dogs may be less likely to cause bite injuries across sexes. The evidence for other effects such as human-directed aggression, human or object mounting, resource guarding, or shyness and anxiety is inconsistent and contradictory. There are few studies specific to females or individual breeds. Conclusions: The evidence for a beneficial effect of desexing is stronger in female than in male dogs; however, there is significant variation between breeds and sexes, and more research is needed to further elucidate these differences and to arrive at individualized evidence-based recommendations for clinical practice.

Evaluation of the factor structure of the Canine Behavioural Assessment and Research Questionnaire (C-BARQ) in European Portuguese.

The human-dog relationship is thought to be the oldest domestic animal partnership. These relationships are complex and can become problematic when they become dysfunctional. The most common signs of dysfunctional human-dog partnerships are behaviour problems that, when unidentified and uncorrected, can be a clear danger to both species and the public. The Canine Behavioural Assessment and Research Questionnaire (C-BARQ) is a widely implemented instrument to evaluate dog behaviour proven to be useful across various cultures. A European Portuguese 78-item version based on the 100-item C-BARQ was developed and its psychometric properties evaluated. The resulting questionnaire has a 13-factor structure accounting for 58.42% of the total variance with Cronbach’s alpha values ranging from 0.902 and 0.721, showing excellent to respectable consistency. The original factors, Dog-Directed Aggression and Dog-Directed Fear, both loaded strongly onto a joint factor renamed Dog Associated Fear/Aggression, explaining the 13-factor structure compared to the previously found 14-factor structure. In the European Portuguese C-BARQ only two items did not load onto their expected factor. Results show that the questionnaire measures universal dog behaviours that are evident to most owners. Our results suggest that the European Portuguese version of the C-BARQ can be used to characterize the behaviour of dog populations and is adequate for use in animal shelters to help match dogs with new owners and in clinical settings to identify behaviour problems in veterinary patients before they become unmanageable. The European Portuguese C-BARQ could be of vital importance in helping to resolve behavioural problems in owned dogs before they become so serious as to lead to abandonment or euthanasia, diminishing the pressure on municipal kennels and greatly improving canine welfare.

The interaction between behavioural traits and demographic and management factors in German Shepherd dogs

As companion animals, a dog’s lifestyle is mainly determined by its owner. Discrepancies between the dog’s preferences and the owner’s lifestyle might lead to the occurrence of unwanted behaviours that affect both the owner-dog relationship and the dog’s welfare. The aim of this study was to identify behavioural traits that are characteristic of German Shepherd dogs (GSDs), and to analyse the relation between behavioural traits and demographic and management factors. Dog owners from the UK and Sweden were asked to complete two surveys, the established C-BARQ behavioural survey and a lifestyle survey developed for the study. A principal component analysis was applied to determine behavioural components for GSDs. Fifteen components were found to sufficiently explain the variance in the responses to C-BARQ, with the components Stranger-directed aggression and Dog-directed aggression explaining the greatest proportion of the variance in the data (12% and 10%, respectively). Linear models were then applied to assess the relationship between behaviour components and lifestyle factors using backward elimination to identify the model that best predicted the behaviour component. The cohort (UK or Sweden) and the age of the dog were associated with the highest number of behaviour components. This study showed that various demographic and management factors were associated with the expression of behavioural traits in GSDs. Results from this analyses may help to understand the interaction between the expression of external factors and dog behavioural traits and thus, improve the well-being of dogs and owners by reducing problem behaviours.

Lack of association between paw preference and behaviour problems in the domestic dog, Canis familiaris

Evidence suggests that paw preferences are related to emotional functioning in the domestic dog. Whether motor bias in this species is related to the display of behaviour problems, which often have their basis in emotional reactivity, is still unknown. This study therefore explored the relationship between lateralised motor behaviour in the form of paw preferences and the occurrence of canine behaviour problems. Fifty-two dogs presenting with one or more behaviour problems, and 61 control animals, had their paw preferences assessed using the commonly employed Kong™ ball test. The dogs’ behavioural profile was determined using the C-BARQ, a psychometric tool designed to provide standardized evaluations of canine behaviour. Analysis revealed a roughly equal split in the proportion of dogs classified as ambilateral and lateralised, although dogs were more like to be ambilateral than left- or right-pawed. Dogs differed significantly in their behavioural profile, with animals in the behaviour problem group displaying more severe patterns of stranger- and dog-directed aggression and fear, non-social fear and touch sensitivity than those in the control group. There was no significant difference in the distribution, direction or strength of the dogs’ paw use between the two groups of animals. The dogs’ paw preference classification was significantly associated with one of the C-BARQ subscale scores, namely stranger-directed aggression, with left-pawed dogs having lower scores on this subscale than right-pawed or ambilateral animals. The direction of the dogs’ paw use in the behaviour problem group was significantly correlated with C-BARQ scores for the subscales of stranger-directed aggression, stranger-directed fear and attention-seeking behaviour, with higher subscale scores associated with increasing right-pawedness. There was no significant correlation between the direction of the dogs’ paw use and any of the other C-BARQ subscale scores. The strength of the dogs’ paw preferences was not significantly correlated with any of the C-BARQ subscale scores for either the control or behaviour problem group of animals. Canine sex was not significantly related to either the dogs’ paw preferences or the presentation of behaviour problems. Overall, this study provides little evidence in support of a relationship between paw preference and the occurrence of behaviour problems in the domestic dog. Further, longitudinal, work is recommended in an effort to unravel the ontogeny of lateralisation and its association with emotional reactivity in this species.

Effects of surgical and chemical sterilization on the behavior of free-roaming male dogs in Puerto Natales, Chile

Population management of free-roaming domestic dogs (Canis lupus familiaris) is of interest due to the threat these animals pose to people, other animals and the environment. Current sterilization procedures for male dogs include surgical and chemical methods. However, little is known about how these procedures affect their behavior. The primary objective of this study was to investigate changes in selected behaviors following chemical and surgical sterilization in a male free-roaming dog (FRD) population in southern Chile. We also examined the association between serum testosterone levels and behaviors thought to be influenced by circulating androgens. A total of 174 dogs were randomly assigned to either a surgical or chemical sterilization group, or a control group. At the onset of the intervention period, 119 dogs remained and 102 dogs successfully completed the study. Each dog was monitored pre- and post-intervention using video recordings, GPS collars, and blood samples for the measurement of testosterone. Analysis of behavior revealed that surgically castrated dogs showed no reduction of sexual activity or aggression when compared to their pre-intervention behavior. Chemically sterilized dogs showed a statistically significant increase in dog-directed aggression, but no change in sexual activity. There was no change in home range size in any groups between the pre- and post-intervention measurement. We found no consistent association between levels of serum testosterone concentration and behavioral changes in any of the groups. This study presents the first detailed behavioral observations following surgical and chemical sterilization in male FRDs. The information generated is highly relevant to communities struggling with the control of FRDs. Complementary studies to further our understanding of the effects of male sterilization on the behavioral and reproductive dynamics of FRD populations are needed.

"Reactivity to stimuli" is a temperamental factor contributing to canine aggression.

Canine aggression is one of the most frequent problems in veterinary behavioral medicine, which in severe cases may result in relinquishment or euthanasia. As it is important to reveal underlying factors of aggression for both treatment and prevention, we recently developed a questionnaire on aggression and temperamental traits and found that “reactivity to stimuli” was associated with aggression toward owners, children, strangers, and other dogs of the Shiba Inu breed. In order to examine whether these associations were consistent in other breeds, we asked the owners of insured dogs of Anicom Insurance Inc. to complete our questionnaire. The top 17 contracted breeds were included. The questionnaire consisted of dogs' general information, four items related to aggression toward owners, children, strangers, and other dogs, and 20 other behavioral items. Aggression-related and behavioral items were rated on a five-point frequency scale. Valid responses (n = 5610) from owners of dogs aged 1 through 10 years were collected. Factor analyses on 18 behavioral items (response rate over 95%) extracted five largely consistent factors in 14 breeds: “sociability with humans,” “fear of sounds,” “chase proneness,” “reactivity to stimuli,” and “avoidance of aversive events.” By stepwise multiple regression analyses, using the Schwartz's Bayesian information criterion (BIC) method with aggression points as objective variables and general information and temperamental factor points as explanatory variables, “reactivity to stimuli,” i.e., physical reactivity to sudden movement or sound at home, was shown to be significantly associated with owner-directed aggression in 13 breeds, child-directed aggression in eight breeds, stranger-directed aggression in nine breeds, and dog-directed aggression in five breeds. These results suggest that “reactivity to stimuli” is simultaneously involved in several types of aggression. Therefore, it would be worth taking “reactivity to stimuli” into account in the treatment and prevention of canine aggression.

Analysis of Associations between Behavioral Traits and Four Types of Aggression in Shiba Inu

ABSTRACTCanine aggression is one of the behavioral problems for which veterinary behaviorists are most frequently consulted. Despite this, the classification of canine aggression is controversial, and there are several classification methodologies. While the etiology of canine aggression differs among the types of aggression, the behavioral background underlying aggression is not well understood. Behavior trait-based evaluation of canine aggression would improve the effectiveness and efficiency of managing canine aggression problems. We developed a questionnaire addressing 14 behavioral items and items related to four types of canine aggression (owner-, child-, stranger- and dog-directed aggression) in order to examine the associations between behavioral traits and aggression in Shiba Inu. A total of 400 Shiba Inu owners recruited through dog events (n=134) and veterinary hospitals (n=266) completed the questionnaire. Factor analysis sorted the behavioral items from both the event and clinic samples into four factors: “sociability with humans,” “reactivity to stimuli,” “chase proneness” and “fear of sounds.” While “reactivity to stimuli” correlated significantly positively with all of the four types of aggression (P=0.007 to <0.001), “sociability with humans” correlated significantly negatively with child- and stranger-directed aggression (P<0.001). These results suggest that the behavioral traits involved in canine aggression differ among the types of aggression and that specific behavioral traits are frequently simultaneously involved in several types of aggression.

Factors associated with aggressive responses in pet dogs

This study used The Canine Behavioral Assessment and Research Questionnaire (C-BARQ) and regression models to explore the relative importance of dog and owner characteristics, living environment and owner–dog interaction to household dogs’ aggressiveness towards strangers, owners and other dogs. Exploratory factor analysis revealed 10 interpretable factors from the Chinese translation of C-BARQ: stranger-directed aggression, owner-directed aggression, dog-directed aggression, social fear, nonsocial fear, separation-related behavior, attachment or attention-seeking behavior, trainability, excitability and pain sensitivity. The factor structure of our study largely resembled that reported in Hsu and Serpell (2003) and van den Berg et al. (2006; Dutch translation of C-BARQ) . All factors of the translated C-BARQ have adequate reliability (Cronbach α : 0.74–0.93) and are thus suitable for measuring temperament traits in Taiwan's pet dogs. Intrinsic and environmental variables important to the three aggression subscales were not entirely the same, but breed ( P ≤ 0.020) and physical punishment ( P ≤ 0.053) had significant relationships with all of them. Golden Retriever scored the lowest while dogs subjected to physical reprimands scored significantly higher on aggression subscales. In addition, higher scores on stranger-directed aggression were associated ( P ≤ 0.027) with living in rural areas, in houses with yard space and with more household members and being acquired either as puppies or for guarding purposes. Higher scores on owner-directed aggression were associated ( P ≤ 0.040) with male and older dogs, being neutered/spayed, having female owners, fewer other dogs in the household and being kept outside the house. Higher scores on dog-directed aggression, on the other hand, were associated ( P ≤ 0.050) with living in houses with either yard space or more household members and with spending less time with owners. Stranger- and dog-directed aggression had more important intrinsic and environmental variables common to them than did owner-directed aggression, which suggests that aggression towards owners may be regulated by different mechanisms from aggression towards strangers and other dogs. Although no causal relationship between dog aggression and environmental variables can be implied from observational studies, the results of this and other studies lend support to the possibility of reducing dogs’ aggressive responses through proper management by owners.

A comparison between a direct and an indirect method for assessing aggressiveness in dogs

s 55 organized by Japan Kennel Club in 2008 and 2009. In this study we focused on the fear and the reactivity as candidate temperament factors and chose three dog breeds, Shiba Inu, Labrador retriever and Chihuahua, because they have different tendencies in showing aggressive behaviors (Takeuchi and Mori, 2006). Questionnaires contained questions about general information, 14 items about their dogs’ responses to humans, sounds and small animals, and 6 items about aggression toward owners, children, strangers and dogs. Owners were asked to score their dogs’ response with 5-point frequency scales (1 5 never, 2 5 occasionally, 3 5 sometimes, 4 5 often and 5 5 always). In total, owners of 91 Shiba dogs, of 109 Labrador retrievers and of 100 Chihuahuas volunteered to fill out the questionnaire. At first, factor analysis was conducted using 14 items in each breed, and then factor scores calculated as the average of the questionnaire items comprising each factor was compared between the calm dogs (showing never or occasionally aggressive behavior: scale % 2) and the aggressive dogs (showing aggressive behavior more frequently: scale R 3) in the Shiba breed. The factor analysis resulted in extraction of three factors, i.e., ‘‘reactivity to small animals (F1)’’, ‘‘fear of human (F2: negatively loaded)’’ and ‘‘reactivity to sound and movement (F3)’’, consistently from all the three breeds. The fourth factor, ‘‘fear of sounds (F4)’’ was extracted only from Labrador Retrievers and Chihuahuas. In addition, F1, F2 and F3 are composed of the same items among the three breeds, whereas F4 has the same composition between the two breeds. The Shiba dogs showing owner-directed aggression had significantly higher F3 scores, while those with child-directed and stranger-directed aggressions had lower F2 scores and higher F3 scores as compared with calm individuals, respectively. No such difference was found regarding the dog-directed aggression. These results suggest that the temperament factors such as fear and reactivity may differently contribute to the owner-directed aggression from the stranger (or child)directed aggression in Shiba Inu breed.

Training engagement and the development of behavior problems in the dog: A longitudinal study

Canine behaviour problems have serious welfare implications for dog and owner. Canine behavioural development can be divided into eight stages. Of these, the first year is most critical as it is the period when most social and environmental learning occurs, learned behaviour patterns become established and problem behaviours are most likely to become apparent (Lund et al, 1996). Whilst experiences during the socialisation period are of great importance, dogs may regress and become fearful if exposure to socio-environmental stimuli is not maintained (Dehasse, 1994; Fox, 1978) as both social and environmental learning continue throughout the juvenile period and adolescence. There is evidence of second phase of heightened sensitivity to fear arousing stimuli at the age of 6 months, around the onset of sexual maturity (Fox, 1972; Serpell and Jagoe, 1995), known as the ‘secondary sensitive’ or ‘secondary socialisation’ period. As with the onset of sexual maturity, the exact timing of this phase is variable between breeds and individuals. It may be that some do not go through this ‘secondary sensitive period’ until later adolescence or that it lasts for a greater or lesser part of the adolescent period (Dehasse, 1994; McBride et al. 1995). The present longitudinal study investigated the relationship between behaviour and early experience and management, including training engagement throughout the first year (Thompson et al, in prep.). 51 owners completed questionnaires at the time of first vaccination (A), 6 months (B), 9 months (C) and 12 months (D) of age. Behaviour was assessed using the Canine Behaviour and Research Questionnaire (Hsu and Serpell, 2003), and responses produced scores on 6 subscales which had been validated by the current authors for this age group ( Results showed that dogs attending ‘puppy socialisation/training classes’ or ‘puppy parties/socialisation groups’ prior to 6 months of age had significantly lower total problem behaviour scores than dogs attending other training formats or receiving no training. Dogs attending ‘young dogs classes’ between 6 and 9 months of age also showed a significant reduction in total problem behaviour. Six C-BARQ subscales were used: attachment/attention seeking (AAS); non-social fear (NSF); dog-directed aggression or fear (DDAF); owner directed aggression (ODA); stranger-directed fear (SDF) and separation-related problems (SRP). Analysis revealed differential effects of both the age at which the dog was trained and the type and methods of training used. In summary, results indicate that professional training is beneficial in reducing the incidence of problems behaviour and is most effective when engaged in prior to 6 months of age. Furthermore, class formats providing a combination of obedience training, troubleshooting advice and intra-specific socialisation are most effective in producing well balanced dogs.

Breed differences in canine aggression

Canine aggression poses serious public health and animal welfare concerns. Most of what is understood about breed differences in aggression comes from reports based on bite statistics, behavior clinic caseloads, and experts’ opinions. Information on breed-specific aggressiveness derived from such sources may be misleading due to biases attributable to a disproportionate risk of injury associated with larger and/or more physically powerful breeds and the existence of breed stereotypes. The present study surveyed the owners of more than 30 breeds of dogs using the Canine Behavioral Assessment and Research Questionnaire (C-BARQ), a validated and reliable instrument for assessing dogs’ typical and recent responses to a variety of common stimuli and situations. Two independent data samples (a random sample of breed club members and an online sample) yielded significant differences among breeds in aggression directed toward strangers, owners and dogs (Kruskal–Wallis tests, P < 0.0001). Eight breeds common to both datasets (Dachshund, English Springer Spaniel, Golden Retriever, Labrador Retriever, Poodle, Rottweiler, Shetland Sheepdog and Siberian Husky) ranked similarly, r s = 0.723, P < 0.05; r s = 0.929, P < 0.001; r s = 0.592, P = 0.123, for aggression directed toward strangers, dogs and owners, respectively. Some breeds scored higher than average for aggression directed toward both humans and dogs (e.g., Chihuahuas and Dachshunds) while other breeds scored high only for specific targets (e.g., dog-directed aggression among Akitas and Pit Bull Terriers). In general, aggression was most severe when directed toward other dogs followed by unfamiliar people and household members. Breeds with the greatest percentage of dogs exhibiting serious aggression (bites or bite attempts) toward humans included Dachshunds, Chihuahuas and Jack Russell Terriers (toward strangers and owners); Australian Cattle Dogs (toward strangers); and American Cocker Spaniels and Beagles (toward owners). More than 20% of Akitas, Jack Russell Terriers and Pit Bull Terriers were reported as displaying serious aggression toward unfamiliar dogs. Golden Retrievers, Labradors Retrievers, Bernese Mountain Dogs, Brittany Spaniels, Greyhounds and Whippets were the least aggressive toward both humans and dogs. Among English Springer Spaniels, conformation-bred dogs were more aggressive to humans and dogs than field-bred dogs (stranger aggression: Mann–Whitney U test, z = 3.880, P < 0.0001; owner aggression: z = 2.110, P < 0.05; dog-directed aggression: z = 1.93, P = 0.054), suggesting a genetic influence on the behavior. The opposite pattern was observed for owner-directed aggression among Labrador Retrievers, ( z = 2.18, P < 0.05) indicating that higher levels of aggression are not attributable to breeding for show per se.

Phenotyping of Aggressive Behavior in Golden Retriever Dogs with a Questionnaire

Reliable and valid phenotyping is crucial for our study of genetic factors underlying aggression in Golden Retriever dogs. A mail questionnaire based on the Canine Behavioral Assessment and Research Questionnaire (CBARQ; Hsu and Serpell, 2003, JAVMA 223(9):1293-1300) was used to assess behavioral phenotypes. Owners of 228 Golden Retrievers completed the questionnaire. These dogs had been referred to our clinic for aggression problems several years earlier or they were related to aggressive dogs. In this paper, three sets of results are presented, which indicate that behavior scores from the CBARQ can be applied to genetic studies. First, factor analysis demonstrated that CBARQ items can be grouped into 10 behavioral traits, including three types of aggression: stranger-directed aggression, owner-directed aggression, and dog-directed aggression. The results were remarkably similar to those reported by Hsu and Serpell. The aggression scores showed considerable variation in our dog families, which is a prerequisite for genetic studies. Second, retrospective questions enabled us to study changes in the aggressive behavior of the dogs in the course of time. After an average time interval of 4.3 years, over 50% of the dogs had become less aggressive. Third, we analyzed data obtained with an aggression test of 83 dogs. Two out of the three CBARQ aggression factors were also found in the aggression test data.