Neurodevelopmental scaling is a major driver of brain-behavior differences in temperament across dog breeds.

Behavioral traits like aggression, anxiety, and trainability differ significantly across dog breeds and are highly heritable. However, the neural bases of these differences are unknown. Here we analyzed structural MRI scans of 62 dogs in relation to breed-average scores for the 14 major dimensions in the Canine Behavioral Assessment and Research Questionnaire, a well-validated measure of canine temperament. Several behavior categories showed significant relationships with morphologically covarying gray matter networks and regional volume changes. Networks involved in social processing and the flight-or-fight response were associated with stranger-directed fear and aggression, putatively the main behaviors under selection pressure during wolf-to-dog domestication. Trainability was significantly associated with expansion in broad regions of cortex, while fear, aggression, and other "problem" behaviors were associated with expansion in distributed subcortical regions. These results closely overlapped with regional volume changes with total brain size, in striking correspondence with models of developmental constraint on brain evolution. This suggests that the established link between dog body size and behavior is due at least in part to disproportionate enlargement of later-developing regions in larger brained dogs. We discuss how this may explain the known correlation of increasing reactivity with decreasing body size in dogs.

Why do people buy dogs with potential welfare problems related to extreme conformation and inherited disease? A representative study of Danish owners of four small dog breeds.

A number of dog breeds suffer from welfare problems due to extreme phenotypes and high levels of inherited diseases but the popularity of such breeds is not declining. Using a survey of owners of two popular breeds with extreme physical features (French Bulldog and Chihuahua), one with a high load of inherited diseases not directly related to conformation (Cavalier King Charles Spaniel), and one representing the same size range but without extreme conformation and with the same level of disease as the overall dog population (Cairn Terrier), we investigated this seeming paradox. We examined planning and motivational factors behind acquisition of the dogs, and whether levels of experienced health and behavior problems were associated with the quality of the owner-dog relationship and the intention to re-procure a dog of the same breed. Owners of each of the four breeds (750/breed) were randomly drawn from a nationwide Danish dog registry and invited to participate. Of these, 911 responded, giving a final sample of 846. There were clear differences between owners of the four breeds with respect to degree of planning prior to purchase, with owners of Chihuahuas exhibiting less. Motivations behind choice of dog were also different. Health and other breed attributes were more important to owners of Cairn Terriers, whereas the dog's personality was reported to be more important for owners of French Bulldogs and Cavalier King Charles Spaniels but less important for Chihuahua owners. Higher levels of health and behavior problems were positively associated with a closer owner-dog relationship for owners of Cavalier King Charles Spaniels and Chihuahuas but, for owners of French Bulldogs, high levels of problems were negatively associated with an intention to procure the same breed again. In light of these findings, it appears less paradoxical that people continue to buy dogs with welfare problems.

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.

Changes in blood testosterone concentrations after surgical and chemical sterilization of male free-roaming dogs in southern Chile.

There is a growing interest in chemical sterilization as an alternative to surgical castration in large-scale sterilization campaigns to control canine populations. An important step toward understanding the short-term and long-term effects of chemical sterilants is to determine their impact on blood testosterone concentrations, particularly as these could influence dog behavior after treatment. A field trial was conducted with 118 free-roaming male dogs in the Chilean Patagonia, where 36 dogs were chemically sterilized using EsterilSol, 39 dogs were surgically castrated, and 43 dogs remained intact as controls. Blood testosterone levels were determined at four time periods: on enrollment 6 months before treatment (t-6m), at the time of treatment (t0, within one hour after surgical castration or chemical sterilization and during a concurrent 2-week period for the control group), four (t+4m), and six (t+6m) months after treatment. Intrinsic and temporal factors were evaluated; age was significantly associated with testosterone, where dogs 2- to 4-year-old had the highest testosterone concentrations (P = 0.036), whereas body weight and body condition scores were not associated with testosterone; testosterone concentration was not influenced by time of day, month, or season. After treatment (t+4m and t+6m), all of the surgically castrated dogs had testosterone concentrations below 1.0 ng/mL. On the basis of this cut point (<1 ng/mL), testosterone remained unchanged in 66% of the chemically sterilized dogs at both t+4m and t+6m; it remained low for 22% of dogs at both t+4m and t+6m; it was unchanged at t+4m but low at t+6m in 9% of dogs; and, it was low at t+4m but reverted back to unchanged at t+6m in one dog (3%). Incidentally, testosterone in chemically sterilized dogs increased dramatically within 1 hour of treatment (t0), more than doubling (131%) the concentration of control dogs at the time of treatment (t0), likely because of severe necrosis of interstitial cells. The use of EsterilSol as a method of sterilizing dogs had a variable effect on blood testosterone concentrations. Approximately, 30% of chemically sterilized dogs had a reduced testosterone concentration (actual maximum, 1 ng/mL) after 6 months, similar to that of surgically castrated dogs. Most chemically sterilized dogs, however, showed no long-term changes in blood testosterone concentrations.

Free-roaming dog control among OIE-member countries.

A questionnaire was distributed to the state veterinary services of all 172 OIE countries to collect data on the different national approaches to dog population control. We used all 81 completed questionnaires with ≥80% of the question answered to identify the different national approaches to the issue. The intensity of the free-roaming dog (FRD) problem was negatively correlated with the value of the UN's human development index recognized for each country. Dog bites/attacks and rabies were the main problems associated with FRDs, and these problems were reported disproportionately by less-developed countries. Dog-control programs (DCP) were more widely used among the more-developed countries. In less-developed countries, DCPs (when they existed at all) tended to employ killing methods (including poisoned baits), that are not recommended on animal-welfare grounds.

Development and validation of a novel method for evaluating behavior and temperament in guide dogs.

Most guide and service dog organizations would benefit from the development of accurate methods for the early evaluation of canine temperament traits. This paper describes the development and validation of a novel questionnaire method for assessing behavior and temperament in 1-year-old guide dogs. Volunteer puppy-raisers scored a total of 1097 prospective guide dogs on a series of 40 semantic differential-type, behavioral rating scales. Principle components factor analysis of these scores extracted eight stable and interpretable common factors: stranger-directed fear/aggression, non-social fear, energy level, owner-directed aggression, chasing, trainability, attachment, and dog-directed fear/aggression. Three of these eight factors exhibited moderate internal consistency (Cronbach's alpha>/=0.72), while the reliabilities of the remaining factors were relatively low (Cronbach's alpha=0.53-0.61). The eight factors were then validated against the guide dog school's own criteria for rejecting dogs for behavioral reasons. The results of this analysis confirmed the construct validity of the puppy raisers' questionnaire assessments of their dogs, and suggested that such methods can provide a useful and accurate means of predicting the suitability of dogs for guiding work. Various modifications to the original questionnaire are proposed in order to enhance its overall reliability.

Evaluation of clomipramine as an adjunct to behavioural therapy in the treatment of separation-related problems in dogs.

Forty-nine dogs showing signs of separation-related problems were randomly assigned to one of three groups: group A (15 dogs) received a placebo twice daily; group B (17 dogs) received clomipramine at 0.5 to 1.0 mg/kg twice daily; and group C (17 dogs) received clomipramine at 1.0 to 2.0 mg/kg twice daily. All the dogs also received behavioural therapy. Their owners were required to complete questionnaires about their dog's behaviour initially, and one, four and eight weeks after the treatment with clomipramine began. Bipolar ratings scales were used to monitor the frequencies of 'general', 'attachment-related' and 'separation-related' behaviours. Kruskal-Wallis tests and Kendall Rank correlations were used to determine any initial differences between the treatment groups, and the association between the initial scores and behavioural changes after one week of treatment with clomipramine. Extended Mantel-Haenszel statistics were used to evaluate the effects of clomipramine treatment versus the placebo, and Page's test was used to assess the effectiveness of behavioural therapy on its own. There were no significant differences in the demographic characteristics of the owners of the dogs assigned to the three groups. The dogs differed slightly in age between groups, and the dogs in the two clomipramine-treated groups were reported as showing problems at a significantly earlier age than those in the placebo group. Clomipramine treatment had a sustained suppressive effect on the dogs' general activity levels, and a more modest suppressive effect on their attachment-related tendency to want much physical contact with their owners. The typical signs of separation-related behaviour problems were not significantly affected by treatment with clomipramine, but behavioural therapy on its own was highly effective in reducing behavioural problems.

Aggressive behaviour in English cocker spaniels and the personality of their owners.

The aim of the study was to determine whether there is an association between the personality of the owners of English cocker spaniels and the expression of aggressive behaviour by their dogs. Two-hundred-and-eighty-five owners of purebred English cocker spaniels completed the Catell 16 Personality Questionnaire. One-hundred-and-twenty-eight of them owned 153 dogs previously classified as being 'low' in terms of aggressiveness and 157 owned 172 dogs classified as being 'high' in terms of aggressiveness. Both groups of owners were similar in terms of a variety of demographic variables, including the number of adults and children in the household, the type of house and the sex of the owner. The dogs in both groups were similar in age, age when acquired and sex ratio. Analyses of the data using unpaired t-tests revealed that the owners of high aggression dogs were significantly more likely to be tense (P < 0.001), emotionally less stable (P < 0.01), shy (P < 0.01) and undisciplined (P < 0.05) than owners of low aggression dogs.