Single- and multi-trait animal model in the silver fox evaluation
2002
Wierzbicki, H. | Filistowicz, A. (Agricultural Univ., Wroclaw (Poland). Dept. of Genetics and Animal Breeding)
Data on 4,435 silver foxes were used in the estimation of genetic parameters and genetic trends for 4 traits evaluated according to Polish grading standard. The graded traits were: body size (BS), colour type (CT), purity of silvering and coat colour (PSCC), and coat quality (CQ). (Co)variance components were estimated by the restricted maximum likelihood method (REML) using the average information (AI) algorithm. A linear model that included herd, year of birth and birth season as fixed effects, and additive genetic as a random effect was used in both, single- and multi-trait analyses. The annual genetic trend of the studied traits was estimated as a regression of breeding value on time. Comparable estimates of heritability were derived using single- (ranging from 0.192 for CQ to 0.356 for CT) and multi-trait (ranging from 0.191 for CQ to 0.345 for CT) models. Genetic correlations were found between CT and PSCC, and CT and CQ (0.47 and 0.43, respectively). The estimated genetic trends were positive for all the traits and ranged from 0.014 to 0.057 when single-trait analysis was used or they ranged from 0.017 to 0.057 when multi-trait analysis was applied.
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