TABLE 2

Estimated genetic parameters in a population of laying hens

ParameterClassical analysesaEquations 4 and 5
Phenotypic variance13,706b13,725c
Direct genetic variance917***960***
Associative genetic variance132**
DA genetic covariance99 NS
Residual correlation0.12***0.09***
% heritable variationd6.7%20.0%
  • Significance levels were obtained from likelihood-ratio tests comparing the full model to the model omitting the term of interest. **P < 0.01; *** P < 0.001; NS, not significantly different from zero; DA, direct–associative.

  • a In this analysis, the term ZSaS was omitted from the model (Equation 4).

  • b Obtained as Embedded Image.

  • c Obtained as Embedded Image.

  • d The percentage of heritable variation was Embedded Image, in which Embedded Image was obtained from Equation 2 by replacing true values by the corresponding estimates, giving 960 + 2 × 3 × 99 + 32 × 132 = 2742 days2. (In the classical analyses Embedded Image).