Association between prospective owner viewing of the parents of a puppy and later referral for behavioural problems

A case-control study was designed to test whether there is an association between the owners seeing the mother of a puppy, and later development of behavioural problems. The sample consisted of dogs that were seen by animal behaviourists (members of the Association of Pet Behaviour Counsellors) and equivalent dogs (without a behavioural problem, but the owners would consider referral to an animal behaviourist were the dog to develop a behavioural problem) seen at a veterinary practice that referred to each animal behaviourist. After adjustment for confounding factors using multivariable logistic regression, case dogs were more likely to be younger than controls (P?