Heritability of Body Weight and Conformation Traits and Their Genetic Association in Turkeys

Heritabilities were estimated in a strain of Broad Breasted Bronze turkeys for body weight at 8 and 14 weeks of age and body weight, keel length, breast width, body depth and shank length at 21 weeks of age for females and 26 weeks of age for males. Similarly, genetic, environmental and phenotypic correlations were calculated among the seven traits. The strain of turkeys used represented a minimally inbred, intact population selected primarily for reproductive performance. The generation means for the traits in question did not change significantly during the five-year study period. The heritability of body weight varied from 0.31 to 0.41 for male progeny and 0.20 to 0.39 for female progeny. The age at which body weight was taken did not materially affect the size of the heritabilities. Keel length had a heritability of 0.27 to 0.29, breast width 0.19 to 0.32, body depth 0.32 to 0.33 and shank length 0.39 to 0.48 for males and females, respectively. All genetic and phenotypic correlations among the seven traits were positive. All of the phenotypic correlations were statistically significant. Since the genetic correlations were as large or larger than the phenotypic correlations, they too were considered real. The environmental correlations were generally smaller than the genetic correlations with some approaching zero. No obvious genetic antagonisms among these seven traits were noted in this population.