Jaume Fatjó, DVM, DECVBM-CA; Marta Amat, DVM; Xavier Manteca, DVM, MSc, PhD, DECVBM-CA
Unitat de Fisiologia Animal, Facultat de Veterinària, Universitat AutÁnoma de Barcelona, Bellaterra, Spain
Canine aggression problems may impair the welfare of dogs and can be very dangerous for people (Guy et al, 2001). Aggression towards family members is the most common form of aggression seen by veterinary behaviourists, ranging from 20 to 60% of the total of aggression cases (Beaver, 1999).
For many years, most cases of aggression towards family members have been linked to an underlying hierarchical conflict between the dog and one or more members of the human family (O'Farrell, 1992; Borchelt and Voith, 1996; Beaver, 1999). Other reasons for a dog being aggressive towards family members are commonly related to a fear reaction, for instance in situations that cause pain, like severe physical punishment (Askew, 1996; Houpt, 1998).
After a possible medical condition has been ruled out, the diagnosis of aggression towards family members is usually based on two main diagnostic criteria: the context in which aggression occurs and the dog's body language (Overall, 1997; Lindsay, 2001; Mertens, 2002).
According to most clinical descriptions a dominant aggressive dog is supposed to behave in a very assertive way each time the owner challenges the dog's status or a competitive situation arises (O'Farrell, 1992; Askew, 1996). Besides the occurrence of aggression in some specific contexts, the hallmark for diagnosis of this form of aggression is the observation of an offensive posture. Thus, the differentiation between a dominant or a fear related attitude is usually possible on the basis of body posture and facial expression (Houpt, 1998).
The aforementioned paradigm for dominance-aggression has been challenged during the past few years by an increasing number of authors. The main reason for that is that a significant proportion of dogs suspected to be dominant show ambivalent signals during aggressive episodes as well as other more general signs of anxiety (Overall, 1997).
Also, in wild canids and particularly in wolves, low rank individuals often display aggression towards high rank pack members in certain situations, like food protection. Harrington & Asa, 2003; Mech, 1970).
In cases of dog aggression, baring the teeth could be linked to behavioural traits like fearfulness of lack of tolerance to frustration, rather than to an underlying dominant attitude. Aggression shown by some dogs toward their owners would not be the outcome of a dog challenging the social hierarchy, but the inability to withhold an aggressive response (Reisner, 2002). As already suggested by other authors, dominance and dominance-related aggression are not synonymous terms (Overall, 1997).
From a practical perspective, understanding the true underlying motivation in a case of aggression towards family members is crucial to develop a correct treatment protocol. For instance, in different species castration has proved to be effective to control certain forms of offensive but not defensive aggression. Also, behaviour modification protocols and drug therapy could be markedly influenced by the initial diagnosis offered by the veterinarian.
The purpose of this presentation is to discuss diagnosis as well as the treatment protocols for cases of canine aggression directed towards family members.
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