Differences in serotonin serum concentration between aggressive English cocker spaniels and aggressive dogs of other breeds

Aggression is one of the most common behavioral problems in dogs and may have important negative effects on public health, human–animal bond, and animal welfare. There is ample evidence showing a negative correlation between serum serotonin concentration and aggressive behavior in a variety of species, including the domestic dogs. This negative correlation is particularly pronounced in dogs that show impulsive aggression. Data obtained in some previous studies suggest that the English cocker spaniel (ECS) is more likely to show impulsive aggression than other breeds. Therefore, the aim of this study was to analyze possible differences in serum serotonin levels between aggressive ECS and aggressive dogs of other breeds. Nineteen ECSs presented for aggression at the Animal Behavior Service (School of Veterinary Science, Barcelona, Spain) were evaluated and compared with 20 aggressive dogs of other breeds attended at the same center. Serum serotonin levels were measured using an enzyme-linked immunosorbent assay method. Statistical analysis was done using the SPSS 15.0 for Windows. Aggressive ECSs had significantly (P < 0.001) lower levels of serum serotonin than aggressive dogs of other breeds (318.6 ± 67.1 and 852.77 ± 100.58 ng/mL, respectively). Variances were not significantly different between ECSs and other breeds (standard deviation = 449.84 ng/mL vs. 292.47 ng/mL, P > 0.05). This finding may explain why ECSs are more likely to show impulsive aggression than other breeds, and suggests that the ECS could be a good model to study the neurophysiologic mechanisms underlying impulsive aggression.     

Analysis of 1040 cases of canine aggression in a referral practice in Spain

A retrospective study was designed to assess the prevalence and clinical presentation of canine aggression problems in a referral practice in Spain. One thousand forty canine aggression cases seen at the Animal Behavior Clinic (Barcelona School of Veterinary Medicine) were analyzed. Each aggression problem was characterized according to 7 predefined diagnostic categories. Breed and sex-related risk factors were calculated by comparing the aggressive dogs to a control population. Aggression problems were the most common behavior complaint (52.28% of all canine behavior cases). Owner-directed aggression was the most frequent of the aggression complaints (38.55%), followed by aggression towards other dogs (34.85%) and unfamiliar people (21.95%). A mean of 1.4 diagnoses of aggression per dog were established. Social conflict aggression towards family members was the most common diagnostic category (35.34%). Sixty nine per cent of aggressive dogs were males and 31% were females, from which only 11 and 12 percent were neutered respectively. Two breeds, the English cocker spaniel and the Catalan sheepdog, presented a particularly high risk for aggression in the studied population.     

Behavioral characteristics of English Cocker Spaniels with owner-defined aggressive behavior

Information on the behavior of both aggressive and nonaggressive (control) English cocker spaniels (ECS) recruited for genetic analysis is presented. Information from a total of 122 dogs was gathered using questionnaires and owner interviews, resulting in analysis of 52 aggressive (5 aggressive dogs were excluded from the analysis) and 65 control dogs. Owners rated their dogs with 5-point frequency scales for unacceptable behavior toward humans (17 items), fear (20 items), barking (8 items), and aggression toward other dogs (4 items). The results show that serious, repeated growling is the most pronounced single behavior characterizing the aggressive ECS, and this seems to be the most important behavior causing owners to classify their dogs as aggressive. The other main behavior characteristic of the aggressive group was skin-penetrating bites. Snapping and “biting in general” were also frequently reported among these dogs. The objective of this study was to describe some behavioral characteristics of ECS showing owner-defined aggressive behavior, and behavioral differences between these dogs and a group of ECS with excellent behavior.     

Prevalence of aggression and fear-related behavioral problems in a sample of Argentine Dogos in Italy

The Argentine Dogo breed is identified frequently as potentially dangerous in worldwide legislation. To investigate the prevalence of problem behaviors in this breed, 94 Argentine Dogo owners provided information on aggressive and fearful behaviors shown by their dogs (83 males, 98 females) in a questionnaire. The results were consistent with the origin of the Argentine Dogo (i.e., descending from fighting dogs) and subsequent selection exerted to improve hunting qualities. Common aggressive behaviors included predation on small animals (92.0%), intra-specific conflicts (69.5%), and territoriality (i.e., vigilance of territory perimeter, 61.3%; aggression toward people visiting the dog's house, 45.3%; vigilance while inside the owners' car, 33.1%). Aggression directed to the owner was marginally represented. Reactions to leashing, bathing, punishment, sleep disturbance, toy removal, and in other conflict situations occurred in less than 10% of the sample. Reactions to food removal (13.3%) and handling (19.8%) showed higher prevalence. Chasing cars/running people (17.6%) and aggression toward strangers, either those who were friendly (19.1%) or those who seemed threatening on approach (29.4%), were noted. Low anxiety levels reported in social situations confirmed that these reactions were not common (e.g., fear of strangers, children, and unfamiliar dogs ≤10%). Common anxious behaviors were fear of traffic (10.3%), loud noises (36.2%), startling stimuli (30.5%), destructiveness (42.9%), excessive body licking (13.6%), and shyness in novel situations (32.4%). The context and targets of aggression when exhibited by these dogs (e.g., aggression toward animals when outside the dogs' territory, aggression towards people when inside territory) suggest that the Italian law on potentially dangerous dog breeds may be ineffective in preventing Argentine Dogos' aggression to humans. Social hazards could be reduced by promoting proper social exposure and reactions toward people.     

Effect of owner experience,living environment,and dog characteristics on owner reports of behavior of Argentine Dogos in Italy

Previous research reported contrasting results on the effect of owner experience on dog behaviors. This may be because of dog breed genetic variability, differences in expectations, management choices, and attitude toward their dogs by owners of dogs of different breeds. A study of a single breed may help provide a better insight into this issue. A convenience sample of 94 participants, owners of 181 Argentine Dogos, was recruited to provide information on their dogs' behaviors through a questionnaire. Participants were classified according to their previous general experience or inexperience with dogs and whether they had previously owned an Argentine Dogo (expert vs. naive owners). Reasons for getting a dog (companionship, guarding, hunting, breeding) and attendance at dog-training classes were also explored. Pearson chi-square tests and binary logistic regressions were used to analyze the data. Previous inexperience with dogs was associated with a higher prevalence of dogs that were fearful of children and unknown dogs. Naive Dogo owners perceived that their dogs were more obedient and friendly toward strangers but aggressive toward children, than those belonging to Argentine Dogo experts. It also appeared that living environment and the dog's age are critical predictors of many outcome variables. Kennel living was found to be predictive of car and food protection, owner-directed aggression and aggression toward children, whereas house living was associated with fear of loud noises. Changes related to the dogs' age were probably related to behavioral development in the dogs. Destructiveness, excessive body licking, and protective aggression were more common in younger dogs, whereas aggression to unknown dogs was more common in older ones. Protective aggression was more common in males, and fear of startling noises was more common in females. Intact dogs showed a higher probability of having attention-getting behavior, and neutered dogs were more fearful of traffic. Our findings are correlative. Even if causative links cannot be made, our findings certainly provide direction for further investigation.     

Pain-related aggression in dogs: 12 clinical cases

The aim of this retrospective study was to describe the main features of pain-related aggression in dogs. Twelve dogs presented for aggressive problems at the Veterinary Hospital of the Autonomous University of Barcelona, Spain, were included, and a questionnaire was used to gather information on the context of the aggression, body posture during the attack, impulsiveness, and aggressive behavior before the onset of the pain-eliciting condition. The most common cause of pain was hip dysplasia (66.7%), but no relationship was found between the cause of pain and the characteristics of the aggressive behavior. Dogs were classified as having been aggressive before or after the onset of painful condition. Dogs that had not been aggressive before the onset of the pain-eliciting condition were more impulsive (df = 1, χ² = 5.3, P = 0.0209), showed aggression as a result of manipulation context more frequently (df = 1, χ² = 6, P = 0.0143), and adopted a defensive body posture more frequently (df = 1, χ² = 3.733, P = 0.0533) than dogs that had been aggressive before the onset of pain. These results suggest that previous expression of aggressive behavior has a major effect on the pattern of pain-related aggression in dogs.     

Effect of Supplementation With Omega-3 Fatty Acids,Magnesium, and Zinc on Canine Behavioral Disorders: Results of a Pilot Study

Recent discoveries have shown that the chances of a dog developing a behavioral disorder may depend upon a number of factors including nutrition. The current pilot study was designed to provide an assessment of the efficacy of a dietary supplement containing omega-3 fatty acids, magnesium, and zinc on some common behavioral disorders in a population of Iranian domestic dogs. In total, 48 dogs including 6 dogs without any behavior disorder (control group) and 42 dogs with at least 1 common behavioral disorder, namely excessive activity, inappropriate elimination, fearfulness, destructiveness, and aggression toward unfamiliar people and dogs (test group), were given daily oral dose of gelatin capsules of fish oil supplements containing 330 mg eicosapentaenoic acid and 480 mg docosahexaenoic acid. Moreover, all dogs received 12-15 mg/kg of magnesium citrate and 5 mg/kg of zinc sulfate. Data were obtained using a questionnaire that dog owners were invited to fill out 2 times before (Days 0 and 42) and 2 times after the supplement treatment period (Days 84 and 126). The questionnaire asked owners whether their dog had exhibited any of the 6 common behavioral disorders on a 5-point Likert-like scale ranging from 0 (never or very rarely) to 4 (very often). The results showed no significant changes for any of the evaluated behavior disorders scale in the control group. In dogs with behavior disorders, results showed a significant reduction in the median score for the severity of fearfulness (P?=?.0083), destructiveness (P?=?.002), and inappropriate elimination (P < .001). In addition, there were no significant differences in the median score for the severity of excessive activity (P = .162), aggression toward dogs (P = .281), and aggression toward unfamiliar people (P = .09) during the course of the study. Results of the study reported here support the hypothesis that a combination of omega-3 fatty acids, magnesium, and zinc may improve some of the behavioral disorders.     

Characterization of chronic pancreatitis in English Cocker Spaniels

Background: Chronic pancreatitis (CP) is common in dogs. The cause is unknown. In humans, different causes of pancreatitis have histologically distinct appearances. The histopathologic lesions in English Cocker Spaniels (ECS) with CP were noted to be histologically different than those of other breeds with CP. Hypothesis: CP in ECS is distinct from CP in other breeds and is characterized by a duct destruction similar to what is observed in autoimmune CP of humans. Animals: Eight ECS and 9 other breeds with histologically confirmed CP recruited over an 8‐year period and 50 postmortem control dogs with CP. Methods: Clinical, clinicopathological, and ultrasonographic findings were recorded. Histological sections were compared with a normal dog and 59 dogs of other breeds with CP. Immunohistochemistry using anti‐CD3, anti‐CD79a, and anti‐cytokeratin antibodies was used to evaluate distribution and type of lymphocytic inflammation and appearance of pancreatic ducts. Results: Four male and 4 female ECS presented at a mean age of 7.2 years. Clinical signs were similar in ECS and other breeds. The pancreas was enlarged and hypoechoic in 4 ECS and 2 controls. Histopathology was characterized by interlobular and periductular fibrosis and inflammation in ECS compared with intralobular disease in most other breeds. Immunohistochemistry identified prominent anti‐CD3⁺ lymphocytic infiltrates around venules and ducts and a marked absence of interlobular ducts in ECS compared with mixed T‐cell infiltration and ductular hyperplasia in most other breeds with CP. Conclusions and Clinical Importance: CP in ECS is distinct from CP in other breeds and is notably duct destructive.     

Owner complaints of canine behavior in Iran–A preliminary survey

The current survey assessed 17 common behavioral complaints reported by 234 dog owners attending the Small Animal Hospital, University of Tehran using a questionnaire. According to the results, nearly 95% of dog owners reported at least 1 undesirable behavior in their dogs. Aggression toward other dogs and people, jumping up, and excessive barking were the most common behavioral complaints. Owners of large-breed dogs were more likely to complain about their dogs’ aggressive behaviors toward people/dogs and excessive barking compared with owners of small-breed dogs. Dogs without access to a yard were more likely to show phobia-associated behaviors, fearfulness, and separation-related behaviors, whereas those having access to a yard were more likely to show aggressive behaviors toward people/dogs and excessive barking. Interaction of dogs with people and type of reaction used by owners in response to the behavior were also related with some other behavioral characteristics of the animals.     

Canine aggression toward unfamiliar people and dogs

Aggression toward unfamiliar dogs and people is a common problem arising most commonly from fear and territoriality. A number of factors contribute to its development, including socialization deficits, hormones, and genetic and neurophysiologic components. These factors are discussed in this article, as are management and behavior modification approaches for controlling aggression.     

Assessment of serotonin in serum,plasma, and platelets of aggressive dogs

Canine aggression is the most common reason for the referral of dogs to behavior practices. In addition, dog bites represent an important problem for public health and animal welfare. The serotonergic system is believed to play an important role in modulating aggression. The aim of the present study was (1) to assess the suitability of different types of blood samples for measuring circulating serotonin in canine clinical studies, and (2) to investigate the relationship between the serotonergic system and canine aggression. The assessment of serotonin was simultaneously carried out in serum, plasma, and platelets of 28 aggressive and 10 nonaggressive dogs with an enzyme immunoassay technique. The mean serotonin concentration in aggressive dogs was significantly lower than in nonaggressive dogs in all the assayed samples. These findings suggest an inverse relationship between the activity of the serotonergic system and canine aggression. Considering the simplicity of the methodology, the authors propose sampling serum as the most suitable method for measuring circulating serotonin in dogs.     

Predatory aggression in a German shepherd dog

This article presents a clinical case of predatory aggression that represents a problem for public health. The patient was a 2-year-old male German shepherd referred to the behavior clinic at the School of Veterinary Medicine owing to its aggressive behavior toward people and other dogs. The dog tended to form a pack with the other dogs of the household and killed neighborhood dogs, cats, hens, and rabbits. The presumptive diagnosis was “predatory aggression” associated with “territorial and protective aggression.” The risk analysis determined that the dog should be euthanized. Nevertheless, the owner refused, and hence behavior modification and drug therapy were recommended. A year later, the dog killed again (another dog), indicating that despite the drug and behavioral treatment, it is likely that its predatory aggression will never be resolved.     

Is breed-specific legislation justified? Study of the results of the temperament test of Lower Saxony

Beginning in July 2000 legislation in Lower Saxony restricted the keeping of bull terriers, American Staffordshire terriers, pit bull terriers, and 11 other breeds. Exemption was possible after attending an especially developed test. The tests analyzed for breed predisposition for excessively aggressive signaling or aggressive behavior in inappropriate situations, differences in behavior between breeds, and factors differentiating biting from nonbiting dogs.The test results of 415 dogs were analyzed. The test consisted of a veterinary examination; a learning test; situations of dog-human, dog-environment, and dog-dog contact; and obedience. Escalation in aggressive behavior was scored using a scale of 1-7. No aggressive behavior (1 on the scale) was shown by 38.07% of the dogs, 61.69% showed aggressive behavior scored as 2 to 5 on the scale, and 0.24% bit without previous threatening signals (6 on the scale).Concerning a score of 1 on the scale, pairwise comparison (chi-square test) showed significant differences between bull terriers and American Staffordshire terriers (P = 0.004), pit bull terriers (P = 0.01), Doberman pinschers (P = 0.003), and rottweilers (P = 0.009). Concerning scores of 2 to 7 on the scale,, no significant differences were found.Ninety-five percent of the animals reacted appropriately in the test situation. Five percent displayed excessive aggressive signaling or aggressive behavior in inappropriate situations. These displays were associated with unusual movements and the dogs' apparent apprehension. Correlation between test results and owners jerking on the leash or misinterpreting their dogs' behavior and dogs trying to elude physical manipulation was found. No significant difference in behavior between breeds was detected.The results show no indication of dangerousness in specific breeds. Justification for specific breed lists in the legislation was not shown.     

The use of novel stimuli as indicators of aggressive behavior in dogs

To test the predictive value of a doll and an artificial hand, reactions of dogs (n=100) were compared to histories of behavior toward children. Each dog's reaction to the doll and the hand was categorized as normal, fearful, fearfully aggressive, or offensively aggressive. Sixty-five percent (n=37) of the dogs that had a normal or no reaction to the stimuli had a history of being good with children. Eighty-eight percent (n=34) of the dogs that had an aggressive reaction to the doll had a history of aggressive behavior toward a child. Dogs that were fearfully aggressive were significantly more likely to show fearful responses to the doll, and dogs that were either dominant or fearfully aggressive were more likely to exhibit aggression of the same type to the hand. The results of this study indicate that the doll and, to a lesser extent, the hand may be useful components in determining the aggressive tendencies of dogs. The results also point out the major limitations, because the false positives and false negatives are too frequent.     

Association of pruritus with anxiety or aggression in dogs

OBJECTIVE: To evaluate the association between pruritus and anxiety-related and aggressive behaviors in dogs. DESIGN: Cross-sectional survey. ANIMALS: 238 dogs between 1 and 8 years old. PROCEDURES: Information including a score for general degree of pruritus (visual analogue scale from 0 to 10) and frequency of anxiety-related and aggressive behaviors was collected via a survey distributed to clients at 3 privately owned practices. RESULTS: Median score for pruritus was 2.4. Dogs were assigned to 2 groups on the basis of pruritus score (nonpruritic [0 to 2.4] and pruritic [2.5 to 10]). There was no significant difference between pruritic and nonpruritic dogs with regard to aggression or with regard to reactivity to being alone; to thunderstorms or noises; or to unfamiliar people, animals, or objects. Post hoc analysis revealed significantly more reactivity to thunderstorms or noises in dogs treated with glucocorticoids (18/37 [49%]) than in those not administered glucocorticoids (57/197 [29%]). CONCLUSIONS AND CLINICAL RELEVANCE: An association was not detected between pruritus and aggressive, anxious, or fearful behavior in dogs. There was greater reactivity to thunderstorms or noises in glucocorticoid-treated dogs. These findings do not preclude the possibility of a relationship between certain dermatoses or pruritic conditions and behavior. However, a concurrent behavioral abnormality cannot be assumed to result from a dermatosis and be expected to resolve with treatment of only the skin disease. Dogs with behavioral disorders and pruritic disease require primary treatment of both conditions. Additional studies to examine the effect of disease and glucocorticoids on canine behavior are warranted.     

A Livestock Guardian Dog by Any Other Name: Similar Response to Wolves Across Livestock Guardian Dog Breeds

Nonlethal tools for reducing livestock depredations, such as livestock guardian dogs (LGDs; Canis familiaris), reduce lethal management of livestock predators and have been widely adopted by domestic sheep (Ovis aries) producers in the United States. However, compared with their success in reducing coyote (Canis latrans) depredations, commonly used LGD breeds appear less effective against wolves (Canis lupus). With more than 30 distinct LGD breeds found throughout the world, certain breeds may be more effective at deterring specific threats. We compared LGD breeds commonly used in the United States, collectively called whitedogs, with three European breeds selected for boldness toward carnivores, history of use in areas with wolves, lack of aggression toward humans, and size. We collected data on LGD behavior with sheep herds in Idaho, Montana, Oregon, Washington, and Wyoming in 2015 and 2016. We also developed a test to examine LGDs’ response to a simulated encounter with a wolf while on summer grazing range. Results from generalized linear mixed models of proportion of time spent in a given behavior indicate that few significant behavioral differences exist among tested breeds. Kangals tended to be more investigative when engaging a decoy, karakachans more vigilant, and transmontanos more able to decipher a threatening from unthreatening stimulus. Transmontanos also spent less time scanning than whitedogs, and there was a marginally significant effect of karakachans moving more than whitedogs. While these subtle behavioral differences may help livestock producers make tailored decisions in choosing the appropriate LGD for their needs and circumstance, our results suggest that behavioral differences among breeds may be less common than often suggested.     

Effect of prepubertal versus postpubertal castration on sexual and aggressive behavior in male horses

Males horses castrated prepubertally occasionally display stallion-like sexual and aggressive behavior as adults. A retrospective survey of 140 horse owners was undertaken to compare the effectiveness of prepubertal versus postpubertal castration on objectionable sexual and aggressive behavior. Of 94 geldings that had been castrated prepubertally (before 2 years of age), 20% to 30% displayed stallion-like sexual behavior and aggression toward horses, and 5% were aggressive toward people in a stallion-like manner. This occurrence of problem behavior was not significantly different from the occurrence of these behavioral patterns in 46 geldings that had been castrated as stallions (over 3 years of age). When castration was examined as a therapeutic measure to eliminate sexual and aggressive behavior in stallions in which the behavior had become objectionable, it was found that the operation was effective on sexual behavior and aggression toward people in 60% to 70% of horses and on aggression toward horses in 40% of horses.     

Is there a difference? Comparison of golden retrievers and dogs affected by breed-specific legislation regarding aggressive behavior

Between 2000 and 2002, legislation in Lower Saxony insinuated a special dangerousness of certain dog breeds, and controls were imposed on them. Exemption was only possible if the dogs passed a standardized temperament test. In a previous study, test results of 415 dogs belonging to breeds affected by the legislation were analyzed. Ninety-five percent of the dogs showed no indication of disturbed aggressive communication or aggressive behavior in inappropriate situations. Because a control group was not available at that time, these results referred to a comparison between the affected breeds. In this study, golden retrievers were tested and used as control group. Seventy golden retrievers were tested in the temperament test. The order of testing was: veterinary examination, learning test, situations of dog–human-, dog–environment-, and dog–dog-contact, and obedience. Levels of escalation in aggressive behavior were scored using a scale of 1–7. A total of 58.57% of the dogs did not show aggressive behavior (Scale 1). Forty percent displayed aggressive behavior referring to Scale 2, and 1.43% showed aggressive behavior referring to Scale 5. A total of 98.57% of the dogs reacted appropriately, and 1.43% displayed aggressive behavior in inappropriate situations. In the previous study, 95% of the animals reacted appropriately, whereas 5% displayed excessive aggressive communication or aggressive behavior in inappropriate situations. Comparing the results of golden retrievers and breeds affected by the legislation, no significant difference was found. A scientific basis for breed specific lists does not exist. Therefore, legislation in Lower Saxony was changed, and breed lists were withdrawn.     

Deafness prevalence and pigmentation and gender associations in dog breeds at risk

Hearing function was tested in dogs from breeds at risk for pigment-associated congenital sensorineural deafness - Dalmatian, English setter (ES), English cocker spaniel (ECS), bull terrier (BT), Australian cattle dog (ACD), whippet, Catahoula leopard dog, and Jack Russell terrier. Deafness prevalence was highest in Dalmatians and lowest in ECS. Phenotype correlation studies were performed in breeds with >100 brainstem auditory evoked responses (BAER) tested subjects. No gender differences were observed. No differences were seen between black- and liver-spotted Dalmatians, among the ES roan colour varieties, among the ECS parti varieties, or among the ACD colour varieties. Blue eyes were positively associated and patches were negatively associated with deafness in the Dalmatian. Blue eyes were also associated with deafness in the ES and ECS. White BT were more likely than coloured BT to be deaf. Having one or more parent's ear deaf was positively associated with deafness in Dalmatians, ES, and ECS.     

Dominance in domestic dogs—useful construct or bad habit?

The term “dominance” is widely used in the academic and popular literature on the behavior of domestic dogs, especially in the context of aggression. Although dominance is correctly a property of relationships, it has been erroneously used to describe a supposed trait of individual dogs, even though there is little evidence that such a trait exists. When used correctly to describe a relationship between 2 individuals, it tends to be misapplied as a motivation for social interactions, rather than simply a quality of that relationship. Hence, it is commonly suggested that a desire ‘to be dominant’ actually drives behavior, especially aggression, in the domestic dog. By contrast, many recent studies of wolf packs have questioned whether there is any direct correspondence between dominance within a relationship and agonistic behavior, and in contrast to wolves, hierarchical social structures have little relationship with reproductive behavior in feral dog packs. Nor do the exchanges of aggressive and submissive behavior in feral dogs, originally published by S. K. Pal and coworkers, fit the pattern predicted from wolf behavior, especially the submissive behavior observed between members of different packs. In the present study of a freely interacting group of neutered male domestic dogs, pairwise relationships were evident, but no overall hierarchy could be detected. Since there seems to be little empirical basis for wolf-type dominance hierarchies in dogs, the authors have examined alternative constructs. Parker's Resource Holding Potential (RHP) appears to be less useful when applied to domestic dogs than to other species, although it has the advantage of incorporating the concept of subjective resource value (V) as a factor influencing whether or not conflicts are escalated. The authors propose that associative learning, combined with V, can provide more parsimonious explanations for agonistic behavior in dogs than can the traditional concept of dominance.