Dangerous dogs: application of federal regulations

During the last years nearly in all provinces in Germany new, hotly debated rules were published in order to meet the threat dangerous dogs or so-called fighting dogs mean to animals and men. Comparing current regulations of different provinces two categories of rules can be identified: one considering particular breeds as extremely dangerous and the other defining and characterising the dangerous dog. The application of these regulations differs enormously in expenditure and procedure. Recent statistics of all registered dog-bites allow other conclusions than those which seemed to have been relevant for the elaboration of the existing legislation. This is particularly true for the breeds which are considered extremely dangerous. It seems to be more useful to use the expression dangerous dog in general. Routine application of the new regulations have, except from some cases, increased administrative input but have not improved the situation itself. Animals homes are complaining of more "fighting" dogs. The fact that it is extremely difficult to find a new owner for these dogs leads to additional animal health problems. Judgement and treatment of dogs presented to public authorities because of dog-biting has not become any easier and dogs causing severe injury are not even presented. The new regulations are not sufficiently preventive and do not really tackle the cause of the problem of dangerous dogs. The existing regulations were developed under a strong political pressure. Authorities are now calling into question the usefulness and purpose of the new legislation. In the past the problem of dangerous dogs was dealt with using general safety legislation and police regulations offering flexibility. Obviously there is an urgent need to identify countermeasures on a larger scale.     

Recognizing and assessing aggressive behaviour in dogs

Within the population the sensitivity to aggressive behaviour in dogs has increased. The authorities are confronted with a problem: if any incident occurs it is their task to decide whether the dogs involved constitute a threat to other people or whether the charge is only the result of a quarrel between neighbours. For this reason, an examination of the dogs with regard to their aggressive behaviour is necessary. Seen from the biological point of view, aggressive behaviour is one of four possibilities a dog can chose from to solve a conflict. The dog's intention in showing aggressive behaviour is to eliminate disturbances and to maintain a distance in space and time. Aggressive behaviour might also be necessary to acquire or defend resources essential to the dog's life. This is to secure its survival and its success in reproduction. One can see from this that aggressive behaviour is a very important and biologically necessary adjustment factor. However, when living together with man aggressive behaviour might become a problem. For the assessment and the therapy of the problem it is necessary to exa-mine the behaviour shown by the dog with regard to its cause. To be able to do this an exact anamnesis, a medical check, and an examination of the dog on the basis of its display in special situations are necessary. For this reason, exclusively veterinarians with a special further education in the field of behaviour should carry out the examination of dogs.     

Plasma amino acid concentrations in aggressive dogs

Following the hypothesis that metabolic screens may be useful tools in the diagnosis of canine aggression we have investigated the blood plasma amino acid levels of dogs which have been found aggressive (N = 10) against dogs or men in comparison to non-aggressive dogs (N = 10). In summary, the aggressive dogs showed elevated plasma concentrations of the neurophysiological active aromatic amino acids tryptophan (46/171 micromol/l, p < 0,001), tyrosine (38/67 micromol/l, p < 0.01) and histidine (74/91 micromol/l, p < 0.01) and lower lysine concentrations (175/151 micromol/l, p < 0.05), which seems to point to a stress situation of these dogs. The nitrogen metabolism is impaired in the urea-cycle in the conversion of ornithine (17/34 micromol/l, p < 0.01) to citrulline (64/47 micromol/l). Higher levels of branched chain amino acids, especially leucine (122/150 micromol/l, p < 0.01), mainly metabolized in muscles, and isoleucin (60/71 micromol/l, p < 0.05) show a high energy potential.The acidose-stimulator methionine (48/78 micromol/l, p < 0.01) proved elevated. The results show that the changed behavior in the aggressive dogs is also reflected in their free amino acid plasma concentrations, independent of the question whether these data are the cause or the result of the aggressivity.     

Comparison of thyroid analytes in dogs aggressive to familiar people and in non-aggressive dogs

A cross-sectional study was performed in order to examine the association between canine aggression to familiar people and serum concentrations of total thyroxine (TT4), free thyroxine (fT4), thyroxine autoantibodies (T4AA), total triiodothyronine (TT3), free triiodothyronine (fT3), triiodothyronine autoantibodies (T3AA), thyroid stimulating hormone (TSH), and thyroglobulin autoantibodies (TgAA). The subjects were 31 dogs historically aggressive to familiar people and 31 dogs with no history of aggression. Behavioral evaluation and physical examination were completed for each dog in addition to a complete blood count, serum chemistry panel, TT4, fT4 by equilibrium dialysis, TT3, fT3, TgAA, T3AA, and T4AA. Significant differences were found between the two groups with respect to only T4AA, which was increased in the aggressive group, but the concentrations for both groups were within the normal reference range. There were no differences between the two groups in the thyroid analytes most commonly measured by veterinary practitioners evaluating thyroid function in dogs. The results of this study revealed no significant difference between aggressive and non-aggressive dogs in the thyroid concentrations most commonly used to diagnose canine hypothyroidism.     

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.     

Treatment of aggressive testicular tumors in four dogs.

In this report, the authors describe four dogs referred for diagnosis and treatment of unusual and aggressive testicular tumors. For the vast majority of dogs with testicular tumors, orchiectomy is curative. All dogs in this report had surgical resection, and three of four dogs were treated with cisplatin chemotherapy. Cisplatin is widely recognized as the most active agent in testicular cancer in human medicine.     

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.     

Relationship between aggressive and avoidance behaviour by dogs and their experience in the first six months of life

The early experiences of dogs showing signs of avoidance behaviour or aggression were compared with those of dogs from the same clinical population that did not show such behaviour. The occurrence of each behavioural sign was tested for its association with the dog's maternal environment, the environment it experienced between three and six months of age, and the age at which it had been acquired. Non-domestic maternal environments, and a lack of experience of urban environments between three and six months of age, were both significantly associated with aggression towards unfamiliar people and avoidance behaviour. Aggression during a veterinary examination was more likely in dogs from non-domestic maternal environments. There was no significant association with either environment for aggression towards familiar people, or towards dogs.     

Increased number of neurons expressing androgen receptor in the basolateral amygdala of pathologically aggressive dogs

The present study aimed to determine the extent to which the androgen receptor (AR) is directly involved in the hormonal modulation of pathological canine aggressive behaviour in the basolateral nuclear group (BNG) of the amygdaloid body. A stereological quantification of AR-positive neurons was performed in the BNGs of normally behaving and aggressive male dogs. The BNG was selected because it is involved in sexual and behavioural activities that are influenced by androgens. In the aggressive dogs the BNG contained a significantly higher number of AR-positive neurons compared with normally behaving dogs suggesting differences in androgen activity within the BNGs of both the groups. However, additional mechanisms are likely to be involved because the AR-negative fraction of BNG neurons was also increased in the aggressive dogs. It was concluded that most of the AR was unliganded because a cytoplasmic staining pattern of AR positivity was observed in the canine BNG neurons. This indicates that genomic androgen actions, which are mediated through the AR are of minor importance in the testosterone modulation of canine aggression within the BNG. Other non-genomic mechanisms through which androgens may exert their action in the BNG are discussed. The aromatase pathway is suggested to be the main mechanism through which testosterone exerts its action within the BNG.     

Comparison of the efficacy of remote consultations and personal consultations for the treatment of dogs which are aggressive towards their owners

Two groups of 42 dogs which were aggressive towards their owners were enrolled into a study designed to compare the efficacy of remote consultations with direct personal consultations for the treatment of the aggressive behaviour. The level of aggression of the dogs was assessed before and after programmes designed to modify their behaviour. Both programmes resulted in a significant reduction in the aggressive behaviour of the dogs towards their owners, and there was no significant difference between the effectiveness of the recommendations, whether they were made without having seen the dog or during a personal consultation with the dog and its owner.