Age, breed, punishment type, training affect dogs' aggression
medwireNews: Dogs' aggression toward other dogs in the household is associated with increasing age, use of positive punishment/negative reinforcement techniques, and attending ring-craft classes, report UK researchers.
Dog-to-dog aggression while on walks is also associated with positive punishment/negative reinforcement techniques, as well as factors including owners' age, and the age, origin, and breed of dog, they add.
However, these factors explained only a "small proportion of the variance between aggressive and non-aggressive dogs," in the study, and should be seen as having a relatively small influence on dog-directed aggressive behavior, writes the team in Veterinary Record.
Overall, the number of owners in the study who reported their dogs ever being aggressive toward other dogs while on walks was 22%, while the number reporting them ever having been aggressive toward other dogs in the household was 8%.
"At least numerically, aggressive directed towards other dogs outside the household appears to be a particularly serious problem," say Rachel Casey and colleagues from the University of Bristol, who received questionnaire responses from 3897 dog owners between 2007 and 2009.
The team defined aggression as barking, lunging, growling, or biting.
For aggression between dogs in the same household and outside of it, use of any positive punishment/negative reinforcement techniques - rather than only positive reinforcement/negative punishment - increased the risk a significant 2.5- and 2.0-fold, respectively.
The results do not indicate whether the aggressive behavior results from these techniques, or whether owners use them because of existing aggressive behavior, note the researchers.
Dogs that came from rescue centers, or from other sources such as a pet shop or newspaper advert, were a respective 2.4 and 1.8 times more likely to be aggressive toward other dogs outside the household than dogs that originated from a breeder.
These dogs from nonbreeder origins "may have suboptimal early environments, limited opportunity for appropriate socialisation with other dogs, and/or are likely to be passed on to owners with limited advice or information," suggest Casey et al.
The finding that dogs attending ring-craft classes were 3.8 times more likely to be aggressive to other dogs in their household "seems counterintuitive," they say. However, showing owners are likely to have multiple dogs in the house, which could explain the association, they conclude.
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By Sarah Guy, medwireNews Reporter