Using egg production longitudinal recording to study the genetic background of resilience in purebred and crossbred laying hens

Table 3 Estimates of genetic parameters estimates with their standard error in parentheses for pure- and crossbred layers of the BD line

	EP	LNVAR	SKEW	AUTO-R
Genetic variance
\(\sigma_{{a_{p} }}^{2}\)	325 (29)	0.137 (0.012)	0.027 (0.006)	0.006 (0.001)
\(\sigma_{{a_{c} }}^{2}\)	96 (19)	0.055 (0.015)	0.016 (0.013)	0.009 (0.002)
Residual variance
\(\sigma_{{e_{p} }}^{2}\)	2400 (27)	1.022 (0.011)	1.236 (0.011)	0.074 (0.001)
\(\sigma_{{e_{c \cdot 6} }}^{2}\)	293 (9)	0.242 (0.008)	0.369 (0.011)	0.046 (0.002)
\(\sigma_{{e_{c \cdot 7} }}^{2}\)	269 (11)	0.357 (0.014)	0.382 (0.015)	0.049 (0.002)
Total variance
\(\sigma_{{P_{p} }}^{2}\)	2725 (24)	1.159 (0.010)	1.264 (0.010)	0.08 (0.001)
\(\sigma_{{P_{c \cdot 6}^{*} }}^{2}\)	2078 (64)	0.256 (0.008)	2.586 (0.079)	0.327 (0.010)
\(\sigma_{{P_{c \cdot 7}^{*} }}^{2}\)	2173 (88)	0.371 (0.014)	3.063 (0.119)	0.396 (0.016)
Genetic parameters
\(h_{P}^{2}\)	0.12 (0.01)	0.12 (0.01)	0.02 (< 0.01)	0.08 (0.01)
\(h_{c \cdot 6}^{2}\)	0.05 (0.01)	0.21 (0.06)	0.006^a (0.005)	0.03 (0.01)
\(h_{c \cdot 7}^{2}\)	0.04 (0.01)	0.15 (0.04)	0.005^a (0.004)	0.02 (0.01)
\(r_{pc}\)	0.52 (0.14)	0.47 (0.16)	0.37 (0.40)	0.56 (0.17)

The variances reported are the variances estimated by the bivariate analyses with the same trait in purebreds and crossbreds analyzed jointly
EP total number of eggs laid per layer between 25 and 83 weeks of age, LNVAR natural logarithm of the variance of the deviations between the observed phenotype and the average of the batch, SKEW skewness of the distribution of these deviations, AUTO-R lag-one autocorrelation of these deviations
\(\sigma_{{a_{p} }}^{2}\): additive genetic variances for purebreds; \(\sigma_{{a_{c} }}^{2}\): additive genetic variances for crossbreds; \(\sigma_{{e_{p} }}^{2}\): residual variances for purebreds; \(\sigma_{{e_{c \cdot n} }}^{2}\): residual variances for r crossbreds, where \(n\) is the number of hens in the cage; \(\sigma_{{P_{p} }}^{2}\): total variance for purebreds; \(\sigma_{{P_{c \cdot n}^{*} }}^{2}\): total variance for crossbreds; \(h_{P}^{2}\): heritability estimates for purebreds; \(h_{c \cdot n}^{2}\): heritability estimates for crossbreds; \(r_{pc}\): genetic correlation between purebred and crossbreds
^aIndicates \(h^{2}\) not significantly different from 0 (see “Estimation of variance components for the same trait between purebreds and crossbreds” section about the LRT)

ISSN: 1297-9686