For MY, the permanent environment of the ewe was not included in the model because its variance was not significantly different from 0. Our estimate of the genetic correlation between direct and maternal effects was in the range of those obtained in previous studies, which varied from -0.52 [ 29] to +0.52 [ 30].
All the observers were required to rate the permanent environment of all the walking paths once.
The model included the fixed effect of CG, age fitted as a co-variable (age of buffalo at calving, linear and quadratic) (except for AFC) and the random effects of additive genetic value, permanent environment (except for AFC) and residual.
Examples of estimated genetic correlations and correlations of permanent environment effects for an early, mid and late week of production are given in Tables 2 and 3, respectively, in each case for both dams and sires.
$ a m, a f genetic effects, pe m, pe f permanent environment effects for male and female fertility respectively #Degree: 0 = constant, 1 = linear regression, 2 = quadratic regression, 3 = cubic regression In the analyses presented, a cubic polynomial (m = 3) was used to model the fixed effect of age on fertility, as this described the observed mean weekly fertility profile.
The same tables were applied to assess the permanent environment and current environment for all the paths.
Heritability of body weight was high, varying between 0.46 and 0.60, and permanent environment was responsible for 6%to9%9% of the total variability.
Since the use of random regression models fitting hen and mate genetic and permanent environment effects simultaneously for fertility of eggs is novel, it was necessary to consider a large array of models to determine which was the most plausible and provided an adequate description of the data.
DYD represent the average performance of a bull's daughters corrected for all fixed effects (such as herd, year, season among others), the permanent environment effect, and also for the genetic contribution of the bull's mate (i.e., half the additive genetic value of the cow's dam).
For the analysis with dataset 2, permanent environment was also included as random effect.
