The effect of breeding schemes on the genetic response of canine hip dysplasia, elbow dysplasia, appearance and behaviour traits

Current dog breeding programmes must be changed if genetic improvement in health and behaviour traits is to be achieved. A computer simulation programme was used to assess the possible genetic improvement in hip dysplasia (HD), elbow dysplasia (ED) and behaviour (BE) traits in a dog population whilst simultaneously selecting for appearance (AP). The structure of the Finnish Rottweiler population was used in the simulation. Over a ten-year period (1989-1998), the realised genetic response to selection in the Finnish Rottweiler population was 0.03 genetic standard deviations (SD) for both HD and ED. The relative selection index weights were iterated in the simulation, accordingly, as 0.4 for both traits. In the current breeding strategies, AP dominates other traits. Present index weights for BE and AP were therefore assumed to be 0.5 and 2.0, respectively. With these assumed current index weights, using best linear unbiased prediction (BLUP) breeding values, neither an increase in the number of breeding candidates nor an increase in the number of screened relatives of the candidates resulted in further genetic response for HD, ED or BE. The desired genetic responses for HD, ED and BE over a period of 10 years could only be attained by changing the relative selection index weights dramatically in favour of these traits. As long as the index weights clearly favoured HD, ED and BE, the increase in the number of breeding candidates, ie in the number of screened dogs, resulted in a further response in these traits. To preserve desired behaviour and to improve health in dog breeds, systematic breeding programmes favouring these traits should be developed, and a greater number of dogs should be screened for health and behaviour. Breeders should stop breeding exhaustively for appearance and place more emphasis on health and behaviour traits.