Table 2.

Estimates of genetic parameters for survival time in three crossbred layer lines using STM

	W1 * WA	W1 * WB	W1 * WC
${\sigma }_A^2$	576 ± 326	1415 ± 583	5310 ± 1386
${\sigma }_c^2$	763 ± 173	1813 ± 287	1832 ± 374
${\sigma }_P^2$	7645 ± 260	10,781 ± 389	15,102 ± 647
$T^2$	0.08 ± 0.04	0.13 ± 0.05	0.35 ± 0.08

Estimates of genetic parameters are shown for survival time

${\sigma }_c^2,{\sigma }_A^2,{\sigma }_P^2$, $T^2$ are cage variance, genetic variance and phenotypic variance (${\sigma }_P^2={\sigma }_A^2+{\sigma }_c^2+{\sigma }_e^2$), $T^2=\frac{{\sigma }_A^2}{{\sigma }_P^2}$ [37], respectively. All variances are in days