Resource Management and Geography - Theses
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ItemDevelopment of a breeding programme for guide dogs( 1979)The aim of this project was to design a breeding programme for guide-dogs which would decrease the proportion of dogs that are unsuitable for guide-dog training. To do this requires information on the traits which cause a dog to be rejected, and on the genetics of these traits. In order to obtain this information I analysed the records of the Royal Guide Dog for the Blind Association of Australia and conducted an experiment to compare four breeds (labrador, kelpie, boxer and german shepherd) and crosses between these breeds. Fearfulness is the most important trait causing dogs to be rejected. Other important traits are distraction by other dogs, excitability, hip dysplasia and aggression. Labradors were the least fearful breed and the heritability of fearfulness was approximately 0.5. Measurements of fearfulness in different situations were correlated indicating that a trait of general fearfulness exists. However there were other traits which affected fearfulness in some situations but not in others. Genetic variation appeared to be most prominent in general fearfulness. Consequently selection against fearfulness should be based on observations in situations relevant to guide-dog work, supplemented with other tests of general fearfulness. Two types of test appear to be mist useful:- 1) Tests using very common but complex and intense stimuli to which all dogs have reached a plateau in habituation. 2) Tests using very unusual stimuli that are not encountered outside the scheduled testing programme. There was no between-litter variation in general fearfulness due to the common environment that litter-mates share up to 12 weeks of age. However increasing experience of novel and busy places between 12 weeks and 12 months decreased fearfulness. Labradors were the least aggressive and least excitable breed, but kelpies showed the lowest distraction by other dogs and the lowest incidence of hip dysplasia. The heritability of these trait was lower than that of fearfulness. None of the important behavioural traits displayed any heterosis, which suggests that these traits have been subject to stabilizing selection in the ancestors of the domestic dog. Consequently the recommended breeding programme is selection within the labrador breed, mainly against fearfulness but also against the other traits. Because males are castrated at approximately 6 months of age some selection of stud dogs must be made at this time. Estimates of heritabilities and genetic correlations suggest that selection against fearfulness at 6 months would decrease adult fearfulness almost as much as selection based on adult performance. However the most efficient selection criterion would use information from a wide range of ages. Selection against the other traits at 6 months is not recommended. Adult fearful could be predicted to some degree from the behaviour of 8-12 week old pups (r = 0.57). With increasing age the accuracy of the prediction steadily improved. Fearfulness in puppies was not more highly heritable than in older dogs and should not be used for selecting breeding stock. Correlations between traits indicate that selection against fearfulness will not cause any detrimental correlated responses and will have some advantageous side effects. Excessive submissiveness and fear of punishment are correlated with general fearfulness, but not with performance of learned tasks. Males were less fearful and excitable but more dog distracted and aggressive than females with the result that the two sexes achieved very similar success rates.