Aggressive Behaviour In Dogs Research Articles

Development of a Device for Assessing the Emotional State of Companion Dogs Based on the Analysis of Vocalizations Associated with Anxiety and Barking

Introduction. Canine behaviour, socialization and interaction of dogs with humans are the key factors to be assessed among the risks inducing the increase of incidents related with development of anxiety in dogs. First of all, the lack of knowledge about the reasons of problem behaviour in animals and the high individual variability of behavioural patterns explain the relevance of this work. Moreover, the different methods used by the practitioners and absence of traceability of the owneranimal interaction record lead to the incorrect accumulation of diverse information about the identification and correction of companion dogs’ problem behaviour. The authors of this article aimed to develop a device for registering anxious and aggressive behaviour in dogs by analysing the intervalograms and spectrograms of vocalizations.Materials and Methods. The recordings of canine vocalizations (250 recordings) were obtained as a result of authors' observations carried out in Rostov-on-Don in the period from spring to autumn 2021. The growth of signal intensity was detected by a noise sensor or microphone. The amplitude and duration of the signal were determined by a microcontroller. The Arduino Integrated Development Environment (IDE) was used for writing a programme and flashing the microcontroller. The timers calculating the number of milliseconds from the beginning to the end of an event were implemented in the programme, also, the counters measuring the number of the events within a certain period of time were used.Results. A flowchart of the device for registering and classifying canine vocalizations, which are considered to be the behavioural anxiety markers, has been developed and described. The algorithm for assessing the type of animal activity during vocalization has been suggested. The device prototype has been developed, which enables determination and sending to a Telegram chat bot the data on dog’s anxiety and activity, as well as on the ambient temperature, based on the calculation and analysis of the vocalizations intervalograms.Discussion and Conclusion. The significance of the present development lies in creation of the hardware and software complex prototype that provides the unbiased analysis of the information about changes in canine behaviour in the real time. The implementation of this complex makes it possible to assess the canine behaviour and provides the opportunity to obtain the new data on probability of behavioural disorders in animals caused by a high level of anxiety. The complex can serve as a prototype for creating the systems for tracking and identifying other animal species’ behaviour (including in the urban settings).

Understanding canine aggression: Neurobiological insights for a complex behavior

The relationship between humans and dogs, as the first domesticated animals, exemplifies a significant aspect of human-animal interaction. During domestication, dogs have undergone behavioral changes to establish closer bonds with humans. However, certain dogs face challenges in fully adapting to their new environment, leading to behavioral disorders such as aggression. One of the most prevalent and dangerous behavioral problems in dogs is aggression, which poses risks to both humans and the dogs themselves, sometimes resulting in euthanasia. Canine aggression can arise from various medical and non-medical factors, including physical problems, endocrine system disorders, infectious diseases, central nervous system diseases, hereditary conditions, as well as racial or personal differences. Evaluating aggression based solely on species, breed, and sex characteristics is insufficient. Accurate diagnosis of aggressive behavior requires integrating findings from diverse diagnostic methods, including serum biochemistry, hormone analysis, urinalysis, electroencephalography, radiography, magnetic resonance tests, and behavioral assessments. However, to gain a comprehensive understanding of canine aggression, it is essential to consider the underlying pathophysiological processes and neurobiology. The management of aggressive behavior in dogs necessitates the implementation of diverse treatment strategies aimed at preventing the manifestation of undesirable behaviors. Within the realm of medical interventions, neutering and pharmacotherapy have emerged as prominent approaches. Neutering has shown effectiveness in mitigating aggression among dogs exhibiting aggressive tendencies. On the other hand, pharmacotherapy involves the utilization of complementary and suppressive pharmacological agents that target primary and intermediate components within the mechanisms underlying aggression. These components encompass neurotransmitter/neuromodulator substances, peptides, enzymes, and hormones, all of which contribute to the pathophysiological processes of aggression. Through the modulation of these factors, pharmacotherapy seeks to offer a comprehensive treatment approach for addressing aggressive behavior in dogs. This review aims to investigate the neurobiological basis of aggression in dogs, considering the underlying pathophysiological processes and the role of neurotransmitter/neuromodulator substances, neuropeptides, peptides, enzyme systems, and hormones. Accurate diagnosis and understanding of canine aggression are crucial for the development of effective medical and alternative treatment methods.

Review on Selected Aggression Causes and the Role of Neurocognitive Science in the Diagnosis.

Simple SummaryAggression in dogs is often a reason for abandonment and/or euthanasia. Recently, knowledge about aggression has been subjected to more detailed analysis. In recent years, it has been studied in terms of factors affecting it, such as diet (especially nutritional supplements) and physiology (endocrine system). In addition, recently, new methods of brain research, such as neurocognitive research, have appeared, which enable a significant increase in knowledge about dog behavior, including aggression.Aggression as a behavior is not always desirable, often ends in abandonment and/or euthanasia. However, it is possible to prevent the occurrence of unwanted aggression in domestic dogs. Aggression is not a fully understood phenomenon. In recent years, many studies have focused on the influence of diet and physiology (including the endocrine system) on the emergence of behavioral disorders. In particular, the emphasis was put on nutritional additives such as fatty acids, amino acids, and probiotics. In addition, the possibility of using neurocognition in the observation of abnormal behavior in dogs has also been discussed, which may allow for a more detailed determination of the basis of aggressive behavior in dogs. In this review, the concepts related to aggression and its potential causes have been gathered. In addition, the possible influence of diet and hormones on aggression in dogs has been discussed, as well as the application of neurocognition in the possibility of its diagnosis.

The association of C789A polymorphism in the dopamine beta-hydroxylase gene (DBH) and aggressive behaviour in dogs

The genetic basis of aggressive behaviour has been examined extensively, including analysis of genes encoding neurotransmitters, signalling molecules and regulatory enzymes, as well as their synthesis and degradation. Dopamine beta-hydroxylase, an enzyme catalysing the conversion of dopamine into norepinephrine in synaptic endings, significantly affects the modulation of emotional states and behaviour. The aim of this study was to determine the association of C789A polymorphism in the canine dopamine beta-hydroxylase gene (DBH) and aggressive behaviour in dogs. A total of 110 dogs of different breeds were analysed. All animals were classified according to their individual behavioural characteristics, defined by a veterinary interview and observation. Polymorphism was analysed using ACRS-PCR (amplification created restriction site-polymerase chain reaction) method. Significant differences in DBH genotypes and allele frequency between aggressive and non-aggressive dogs were observed (χ2 = 16,232, P = 0.0003). In aggressive dogs, the CC genotype (0.788) and C allele (0.815) were most frequent while in non-aggressive dogs, their frequencies were significantly lower (0.361 and 0.404, respectively). The obtained results indicate that DBH is a promising candidate gene for canine behavioural study.

TMS improves anxious aggressive behaviour in dogs: A case study

Background Accelerated high frequency repetitive transcranial magnetic stimulation (aHF-rTMS) has proven to produce fast clinical effects in humans suffering from psychiatric illnesses. Although dogs also frequently present behavioural symptoms similar to mental illness, nothing is known about the clinical influence in this species. A 5-year-old neutered male Belgian shepherd dog was presented with anxious aggressive behaviour. Hypothesis It was hypothesized that an aHF-rTMS treatment over the frontal cortex would improve the dogs’ behaviour and alter its regional cerebral blood flow (rCBF) and monoamines. Methodology An aHF-rTMS protocol was applied twice (3 weeks separated) over the left frontal cortex (5 sessions, 20 Hz, 110% CMT). Each protocol was preceded and followed by a behaviour assessment and a [99mTc]HMPAO-SPECT scan. A Z-score for each VOI at each time point was obtained, a |Z|-score > 3.09 (P-value of 0.001) indicated significant differences. Cerebrospinal fluid (CSF) and serum was analysed for the detection of monoamines. Results An improvement of the dogs’ aggressive behaviour was detected. At baseline, only a decreased rCBF of the left frontal cortex was noticeable (Z-score = −3.87). Twenty-four hours after the first protocol, the perfusion in the left frontal cortex was normalized but decreased in subcortical region (Z-score = −6.97). Twenty-four hours after the second protocol, only the subcortical region was hypo-perfused (Z-score = −6.88). Three weeks after each stimulation protocol, no deviations in the rCBF were found. Parallel changes (over time) of 3,4-Dihydroxyphenylacetic acid (DOPAC) concentrations in the serum and CSF were present ( Table 1 ). Conclusion This case study demonstrates that a single day aHF-rTMS treatment reduces a dogs’ anxious/aggressive behaviour. This was accompanied by immediate and long-lasting alterations in the rCBF and DOPAC concentration. Thereby, this study confirms the interaction between the frontal cortex and the subcortical region in behaviour in dogs and puts DOPAC forward as possible biomarker.

Managing the Risk of Aggressive Dog Behavior: Investigating the Influence of Owner Threat and Efficacy Perceptions.

Aggressive behavior in pet dogs is a serious problem for dog owners across the globe, with bite injuries representing a serious risk to both people and other dogs. The effective management of aggressive behavior in dogs represents a challenging and controversial issue. Although positive reinforcement training methods are now considered to be the most effective and humane technique to manage the risk of aggression, punishment-based methods continue to be used. Unfortunately, there has been little scientific study into the various factors influencing whether dog owners choose to use positive reinforcement techniques to manage aggression in their dogs. As such, current understanding of how best to encourage and support dog owners to use these methods remains extremely limited. This article uses a survey methodology based on protection motivation theory (PMT) to investigate the factors that influence owner use of positive reinforcement methods to manage aggressive behavior, in an attempt to understand potential barriers and drivers of use. In addition, the article provides an initial exploration of the potential role of wider psychological factors, including owner emotional state, social influence, and cognitive bias. Findings show that the perceived efficacy of positive reinforcement methods and the perceived ability of owners to effectively implement the technique are both key factors predicting future intentions and current reported use. Future interventions should focus on enhancing owner confidence in the effective use of positive reinforcement techniques across multiple scenarios, as well as helping owners manage their own emotional responses when they encounter challenging situations and setbacks.

Relationship between Motor Laterality and Aggressive Behavior in Sheepdogs

Sheepdogs’ visuospatial abilities, their control of prey-driven behavior and their motor functions are essential characteristics for success in sheepdog trials. We investigated the influence of laterality on 15 sheepdogs’ (Canis familiaris) spontaneous turning motor pattern around a herd and on their behavior during the first encounter with sheep in a training session. The most relevant finding of this research was that the dogs displayed significantly more aggressive behavior toward the sheep when turning in a counterclockwise direction around the herd. Considering that in counterclockwise turns the sheep were in the dogs’ left visual hemifield, the high frequency of aggressions registered during counterclockwise turns suggests right hemisphere main activation. Overall, our results revealed the existence of a relationship between motor lateralization and aggressive behavior in dogs during sheepdog training and have practical implications for sheepdog training.

Aggression toward Familiar People, Strangers, and Conspecifics in Gonadectomized and Intact Dogs.

Gonadectomy is widely used to treat and prevent behavior problems including the aggressive behavior of dogs. The aim of this study was to determine whether aggressive behavior toward familiar people, strangers, or other dogs was significantly different in dogs gonadectomized at various ages vs. intact dogs using the Canine Behavioral Assessment Research Questionnaire (C-BARQ) with multivariate analysis. Of 15,370 initial surveys, those for dogs reported to have been gonadectomized at less than 6 weeks of age or to correct a behavior problem, and those with incomplete answers to questions regarding independent or dependent variables were excluded, leaving 13,795 for the analysis of aggressive behavior toward familiar people: 13,498 for aggressive behavior toward strangers and 13,237 for aggressive behavior toward dogs. Aggressive behavior was defined (a) using mean scores for all questions on the C-BARQ for aggressive behavior (range 0–4) and (b) comparing dogs with no aggressive behavior (all questions answered 0) to dogs with moderate or severe aggression (at least one score of 2, 3, or 4). Data for intact dogs were compared with those for dogs gonadectomized at 6 months or less, 7–12 months, 11–18 months, and >18 months. Neither gonadectomy nor age at gonadectomy showed an association with aggression toward familiar people or dogs. However, there was a low but significant increase in the odds of moderate or severe aggression toward strangers for all gonadectomized dogs compared with intact dogs, but this effect was driven entirely by data for dogs gonadectomized at 7–12 months of age, which were 26% more likely to demonstrate aggression toward strangers. This large, comprehensive study of the relationships between gonadectomy and aggressive behavior in dogs demonstrates that when the many factors affecting aggressive behavior are considered, there is no evidence that gonadectomy at any age alters aggressive behavior toward familiar people or dogs, and there is only a minimal increase in aggression toward strangers. Given the increasing evidence of significant negative health effects of gonadectomy, there is an urgent need to systematically examine other means of preventing unwanted procreation, such as vasectomy and hysterectomy.

Endogenous Oxytocin, Vasopressin, and Aggression in Domestic Dogs.

Aggressive behavior in dogs poses public health and animal welfare concerns, however the biological mechanisms regulating dog aggression are not well understood. We investigated the relationships between endogenous plasma oxytocin (OT) and vasopressin (AVP)—neuropeptides that have been linked to affiliative and aggressive behavior in other mammalian species—and aggression in domestic dogs. We first validated enzyme-linked immunosorbent assays (ELISAs) for the measurement of free (unbound) and total (free + bound) OT and AVP in dog plasma. In Experiment 1 we evaluated behavioral and neuroendocrine differences between a population of pet dogs with a history of chronic aggression toward conspecifics and a matched control group. Dogs with a history of aggression exhibited more aggressive behavior during simulated encounters with conspecifics, and had lower free, but higher total plasma AVP than matched controls, but there were no group differences for OT. In Experiment 2 we compared OT and AVP concentrations between pet dogs and a population of assistance dogs that have been bred for affiliative and non-aggressive temperaments, and investigated neuroendocrine predictors of individual differences in social behavior within the assistance dog population. Compared to pet dogs, assistance dogs had higher free and total OT, but there were no differences in either measure for AVP. Within the assistance dog population, dogs who behaved more aggressively toward a threatening stranger had higher total AVP than dogs who did not. Collectively these data suggest that endogenous OT and AVP may play critical roles in shaping dog social behavior, including aspects of both affiliation and aggression.

His Bark is Worse than His Bite: Perceptions and Rationalization of Canine Aggressive Behavior

Abstract Qualitative methods are increasingly used to investigate the complexities of the dog-human relationship. In order to inform a larger study of human dog interaction, a focus group study was carried out to address the question ‘How is aggressive behavior in dogs perceived and rationalized by people who have experience of dog behavior?’ Six focus groups, including three ‘non-professional’ groups (two groups of dog owners and one group of amateur trainers) and three ‘professional’ groups (a behaviorist group, veterinary group and academic group) were carried out, involving participants who were recruited opportunistically. The focus group transcripts were analyzed using thematic analysis. Findings indicated that participants who do not work with dogs in a professional capacity are largely defensive of dogs when discussing aggressive behavior. However, these participants also discussed factors that make a dog ‘risky’ and how responsible owners manage that risk and the characteristics of ‘dangerous dogs’. For the professional groups, aggressive behavior in dogs presents a barrier to everyday work. They considered working with the owners of dogs showing aggressive behavior and battling anthropogenic stereotypes and misconceptions to be part of the professional challenge. Professionals also contributed views on the nature of ‘dangerous dogs’ and demonstrated awareness of how perceptions could be distorted by the media and propagation of stereotypes. This research highlights the variability of perceptions about canine aggressive behavior. Findings can inform the critical interpretation of quantitative results, and offer a foundation for quantitative study of human directed aggressive behavior in dogs.

Descriptive study on aggressive behavior in dogs from Sorriso and Sinop/MT, Brazil

The goal of this research was to establish and qualify the types of aggressiveness in dogs from Sinop and Sorriso/MT, Brazil, in order to draw a profile of the main breeds raised in these cities. For this purpose, an investigative survey was conducted through interviewing the owners of the animals, to characterize the aggressive behavior of their pets. Five breeds were evaluated (Pit Bull, Doberman, Poodle, Rottweiler and Duchshund), plus one group of mongrel dogs. The concept that the Pitbull is an aggressive dog was put to the test, and breeds like the Poodle and Duchshund showe the highest percentages for almost all forms of aggression assessed. The Rottweiler stood out in the characteristic of aggression toward the owner or family members, and also territorial aggression. The Pitbull had a significant result for aggression toward other animals in the same house. The Poodle and Doberman pinscher breeds, along with Duchshund, proved that are more aggressive that Pitbull and Rottweiler, despite of being small breeds. We could conclude that the behavior study of the breeds, in what concerns to aggressiveness, is of paramount importance to set a breed that best suits the owner’s conditions.

Genetic background of aggressive behaviour in dogs

The background of aggression is very complicated and the basis of its occurrence has not been well explained yet. It is thought that tendency to aggressiveness is an effect of both environmental and genetic factors. Aggression is a very undesirable behavioural trait in dogs living with humans. The aim of this study was to determine the relationship between two polymorphisms: DRD4 intron II VNTR and C/T substitution in exon I HTR2B genes and aggressive behaviour in dogs. The VNTR polymorphism in the DRD4 gene was detected by agarose gel electrophoresis following PCR amplification, whereas C/T substitution in the HTR2B gene was analysed using amplification created restriction site-polymerase chain reaction (ACRS-PCR). A total of 121 dogs of several breeds were analyzed. All animals were classified based on a veterinary interview and observation in two groups: aggressive (n = 21) and non-aggressive (n = 100). Significant differences in DRD4 genotype frequencies between aggressive and non-aggressive dogs were observed (P < 0.05). The study provides a clear evidence of an association of VNTR polymorphism within intron II of the DRD4 gene with the occurrence of aggressive behaviour in dogs. Moreover, the findings give good justification for further research aimed at evaluation of the possibility of using this genetic marker in Marker-assisted Selection.

Differential gene expression in brain tissues of aggressive and non-aggressive dogs

BackgroundCanine behavioural problems, in particular aggression, are important reasons for euthanasia of otherwise healthy dogs. Aggressive behaviour in dogs also represents an animal welfare problem and a public threat. Elucidating the genetic background of adverse behaviour can provide valuable information to breeding programs and aid the development of drugs aimed at treating undesirable behaviour. With the intentions of identifying gene-specific expression in particular brain parts and comparing brains of aggressive and non-aggressive dogs, we studied amygdala, frontal cortex, hypothalamus and parietal cortex, as these tissues are reported to be involved in emotional reactions, including aggression. Based on quantitative real-time PCR (qRT-PCR) in 20 brains, obtained from 11 dogs euthanised because of aggressive behaviour and nine non-aggressive dogs, we studied expression of nine genes identified in an initial screening by subtraction hybridisation.ResultsThis study describes differential expression of the UBE2V2 and ZNF227 genes in brains of aggressive and non-aggressive dogs. It also reports differential expression for eight of the studied genes across four different brain tissues (amygdala, frontal cortex, hypothalamus, and parietal cortex). Sex differences in transcription levels were detected for five of the nine studied genes.ConclusionsThe study showed significant differences in gene expression between brain compartments for most of the investigated genes. Increased expression of two genes was associated with the aggression phenotype. Although the UBE2V2 and ZNF227 genes have no known function in regulation of aggressive behaviour, this study contributes to preliminary data of differential gene expression in the canine brain and provides new information to be further explored.

Evaluating aggressive behavior in dogs: a comparison of 3 tests

Abstract This study assessed the consistency with which aggressive occurred across 3 different provocation tests that are currently used in practice to evaluate the and safety of dogs. The aim of this study was not to validate the tests, but to evaluate tests that are not validated but are nevertheless being used in a legal context in Switzerland, by investigating the hypothesis that 3 different approaches, all claiming to correctly evaluate the of dogs, should be expected to show significant agreement. The same 60 dogs were tested in 3 behavioral tests being used in Switzerland at the time of this study in the year 2003 (Test A: Test of the American Staffordshire Terrier Club; Test B: Halterprufung; Test C: Test of the Canton of Basel-Stadt). Intraspecific behavior and interspecific toward humans that might relate to potential aggressive were of particular interest. The observed agreement among the 3 tests was compared relative to chance using a κ test. Significant but low levels of agreement were found among the 3 tests for the criterion intraspecific behavior (κ = 0.133, P = .014), with the highest correlation between Tests A and B (κ = 0.345, P P = 0. 014), with Tests A and B (κ = 0.220, P = .005) showing the highest correlation. However, significant absolute values of κ were low in all cases. In a further analysis, dogs evaluated to show no signs of potential aggression in the test situations by all 3 tests were eliminated, and the results of the remaining dogs (interspecific behavior, n=23; intraspecific behavior, n=29) were assessed for disagreement in pairwise combinations using a McNemar chi-square test. No significant levels of disagreement were found for intraspecific behavior, however, for interspecific behavior, Tests A and B ( P = .035), and Tests B and C ( P P = 0.11). The inconsistency of the results from different tests suggests test bias at the very least and questions the validity of these tests. Further work examining the validity of each individual test is warranted if they are to be used in a legal context.

Consistency of personality traits in dogs

We investigated the consistency of behaviour over repeated tests in dogs, Canis familiaris. Dogs were tested three times, with an average of 30 and 35 days between tests. The behavioural test used in the study included 10 subtests that exposed dogs to various situations, such as the appearance of an unfamiliar person, play, preylike objects, metallic noise and a suddenly appearing dummy. Studies using the same test with many dogs have revealed five specific personality traits, labelled Playfulness, Chase-proneness, Curiosity/Fearlessness, Sociability and Aggressiveness, and one higher-order, broader dimension, interpreted as a shyness-boldness continuum. We used these traits in the present study. We found significant correlations over the test series in all the specific traits as well as in the Boldness dimension. The magnitude of trait scores for Playfulness, Chase-proneness and Sociability, as well as for the Boldness dimension, was stable between tests. The scores for Aggressiveness and Curiosity/Fearlessness, however, differed between the first two tests: the intensity of behaviour related to fear and aggression decreased from test 1 to test 2, but the intensity of exploratory behaviour increased. This result indicates that these two traits in dogs are sensitive to novelty, although individual differences are also maintained in nonnovel situations. The results suggest that playful, social, exploratory, avoidant and aggressive behaviour in dogs is influenced by stable dispositions; i.e. personality traits, that seem to have been important during the evolution of the domestic dog.

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.

Behavioural testing for aggression in the domestic dog

Aggressive behaviour in dogs is an increasing problem in The Netherlands. In an attempt to find a solution to this problem the Dutch Ministry of Agriculture, Conservation and Fisheries has financially supported a study aimed at developing an aggression test for dogs. The primary goal is to use the test as an instrument for excluding very aggressive individuals of certain breeds from breeding. On the basis of two pilot studies a test has been developed with 43 sub-tests in which a variety of stimuli are presented relating to contexts that are known to elicit aggression in dogs. In the final test, 112 dogs, 75 of which were potentially aggressive breeds (PAB) and a group of 37 “control dogs”, were tested. Questionnaires were used to collect information about the aggressive history of the dog. The results show clear differences in the aggression-eliciting properties of the sub-tests. Dogs with and without biting history differ significantly in their biting/attack behaviour during the test (Mann-Whitney U-test, P = 0.02). This difference is also found for only the PAB-dogs (MWU-test, P = 0.007). For reliability of analysis, 37 dogs were re-tested. The comparison between test and re-test shows a significant correlation for total attack (SPCC = 0.78) and biting/attack (SPCC = 0.68). So that the test can be implemented in practice, two “Models for Unacceptable Aggression (MUAs)” are discussed. To validate the results of the test and the application of the MUAs the results are compared with the biting history of the dogs. The results of an MUA based exclusively on the biting/attack behaviour shows a significant relation with the biting history for all dogs and for the PAB-dogs. On the basis of these results we consider the test to be a useful instrument for the assessment of aggressive tendencies in dogs, provided the test is performed by trained researchers or trained judges and test assistants.

An overview of types of aggressive behaviour in dogs and methods of treatment

In 223 cases of dogs presented to a specialist behavioural clinic in Brisbane, Australia, 87 (39%) were for severe aggression. The classes of aggression included dominance (31.6%), territorial (29%), predatory (12.3%), intermale (12.3%), sibling rivalry (7.9%), fear biting (6%) and idiopathic rage (0.9%). The breeds most represented which attacked humans were the Bull Terrier (16%), German Shepherd and crosses (15%), Cattle dog breeds (Blue Heeler and crosses, 9.2%), Terrier breeds (9.2%), Labrador (8%), Poodle and Cocker Spaniel (both 5.7%) and Rottweiler (4.6%). The dangerous dog list put out by the local Brisbane City Council includes the first three breeds mentioned and the Rottweiler as the top four breeds causing aggression problems. Hospital records in Victoria and Queensland confirm that most damage is caused to humans by Bull Terriers and German Shepherds. Many breeds similar to those in our study are also represented in American data on aggressive breeds. Treatments included obedience training only, restraint only, obedience and restraint, synthetic progestins and obedience, castration, progestins and obedience, castration and obedience, use of chlorpromazine and as a last resort, euthanasia (12.6%). Entire males formed the largest group (44%), followed by castrated males and females (both 21%) and spayed females (15%). Several breeds (Boxer, Briand, Samoyed and St. Bernard) only attacked other animals and birds. This study reinforces evidence that social disruption is caused by aggressive dogs, but it also indicates that many responsible clients seek advice on how to deal with this behavioural problem.

A Behavioral Pharmacological Study of Mafoprazine, a New Phenylpiperazine Derivative

Behavioral pharmacological studies on mafoprazine, a new drug for the prevention of aggressive behavior, were performed to compare its effects with those of an existing drug, azaperone (Stresnil®). The acute toxicity of mafoprazine in mice was slightly stronger than that of azaperone. Mafoprazine showed the following effects (at 0.2 to 2.0 mg/kg, s.c): a decrease in spontaneous motor activity, prolongation of the duration of pentobarbital anesthesia, inhibition of long-term isolation-induced aggressive behavior, inhibition of olfactory bulbectomy-induced hyperemotionality and muricide behavior in mice and rats, and a marked taming and tranquilizing effect on aggressive behavior in dogs. These effects of mafoprazine were qualitatively the same as those of azaperone. Mafoprazine showed cataleptogenicity in rats at 5 mg/kg, s.c or more and motor incoordination in rats at 0.2 mg/kg, s.c or more. In the experiment on operant behavior in rats, the effect of mafoprazine on differential reinforcement of the low rate (DRL) response was almost the same as those of azaperone and chlorpromazine. These results indicate that mafoprazine has substantially the same psychotropic effect as azaperone, while the former has a weaker action on the extrapyramidal system than the latter, suggesting that mafoprazine could be used as a unique aggression-inhibiting drug.