| Abstrakt: |
Data on age and weight at puberty, growth traits and backfat thickness from 1192 gilts were studied. Heritability estimates for age at puberty were −.20±0.14 from a paternal half-sib analysis, and 0.49±0.11 from doubling the intra-sire regression of daughter on dam. The high estimate obtained from the regression analysis was probably due to direct maternal effects of genetic origin. This would be one reason for the highly significant dam effect in the analysis of variance with common environment of littermates accounting for 39% of the variance within farrowings.Genetic correlations of age at puberty with growth traits and backfat thickness were not calculated because of a negative sire component of variance, and because of the bias from maternal effects in the regression analysis. Genetic covariances indicated a positive genetic relationship between age at puberty and weight gain.Phenotypic correlations of age at puberty with the other traits in the analysis were 0.62 with weight at puberty, −.32 with weight per day of age at puberty, −.10 with 42-day weight, −.19 with 140-day weight, −.18 with 42- to 140-day gain, −.44 with gain from 42 days to puberty, −.31 with gain from 140 days to puberty and 0.08 with backfat thickness. Partial correlation coefficients of age at puberty with 42-day weight, 42- to 140-day gain, 140-day to puberty gain and adjusted backfat with the other traits of this group held constant were −.04, −.16, −.31 and 0.01, respectively. The multiple correlation coefficient of age at puberty with these traits was 0.36. |
