[Analysis of systematic environmental and genetic effects on body weight and body measurements in German shepherd dogs].

In dog breeding permission for breeding is only given when the body measurements of the dog are within the lower and upper limits which are defined in the breed standard. Therefore, the objective of this study was to analyse the systematic and genetic effects on body weight and body measurements recorded at licensing in German shepherd dogs (GSD) over a period of 10 years. The data included withers and chest height, chest circumference and body weight from 36,028 breeding dogs born between 1992 and 2003. Birth year, month of birth and region were significant for the traits analysed. Age at breeding approval was significant for the body measurements withers height and chest height and only significant for male dogs for chest circumference. Inbreeding coefficient was significant as a nonlinear covariate for withers and chest height. The genetic parameters were estimated in linear animal models using residual maximum likelihood (REML) and the relationship matrix of 53,429 dogs. Uni- and bivariate analyses were performed for both sexes together and separately for males and females. Heritability estimates for both sexes together were 0.41 +/- 0.01 for withers height and 0.27 +/- 0.01 for body weight. For the other traits studied, heritability estimates were lower with values of 0.20 +/- 0.01 for chest height and 0.13 +/- 0.01 for chest circumference. In the separate analyses for male and female dogs, heritability estimates were higher for females. Additive genetic correlations were at 0.91 to 0.98 between corresponding traits in males and females. The high genetic correlations indicate that selection for conformation traits equally affects both sexes and does not increase sexual dimorphism in dogs.