Analysis of mentality traits in Rhodesian Ridgebacks

Abstract

The object of this study was to identify broader traits from mentality test results in a cohort of 2022 Rhodesian Ridgebacks , to estimate heritabilities for the underlying variables and the broader traits and to predict breeding values for these traits. Data were extracted from the Swedish Dog Mentality Assessment between 1997 and 2012 on 2022 Rhodesian Ridgebacks. Analyses with a mixed model showed that sex, year and month of test, age category, litter, specific test situation and judge had significant influence on the test result, and was included in the model for estimation of heritabilities. These ranged from 0 to 0,22 with standard errors from 0,02 to 0,05. With factor analysis, six factors were derived, describing the broader traits; 1 Play, 2 Fear/exploration, 3 Chase, 4 Distance play, 5 Defense and 6 Sociability. Heritabilities for these traits ranged from 0,09 to 0,31, they were all significant. Breeding values were predicted based on these six traits, and genetic trends estimated for the birth years from 1989 to 2010, which showed an increase in average breeding values over the years for the factors 1, 3, 5 and 6, and a decrease in factors 2 and 4. For all factors but 4 this can be seen as improvements. Factor 4 being the distance play factor showing a decrease in exploration and play behavior over the years, which is hard to interpret in this breed. Selection in this breed is not based on working abilities, and thus the selection intensity disappears among all breeders with separate agendas. Using indexes for the six broader traits may be of help when selecting animals for breeding, to maximize the chances of getting offspring who have the traits desired in a family dog of today, even if goals differ between breeders.