Genetic parameters, reciprocal cross differences, and age-related heterosis of egg-laying performance in chickens

Table 6 Estimates of variances, heritabilities, and repeatabilities for egg quality traits at different ages

Model	Trait	32 weeks of age			54 weeks of age			72 weeks of age			86 weeks of age			100 weeks of age
Model	Trait	\({\sigma }_{p}^{2}\)	h²	r	\({\sigma }_{p}^{2}\)	h²	r	\({\sigma }_{p}^{2}\)	h²	r	\({\sigma }_{p}^{2}\)	h²	r	\({\sigma }_{p}^{2}\)	h²	r
Univariate model	ESI	7.42	0.32	0.41	8.01	0.19	0.43	11.06	0.18	0.42	12.92	0.29	0.50	15.20	0.27	0.47
	ESC	42.94	0.37	0.65	34.00	0.32	0.58	36.21	0.39	0.60	30.46	0.24	0.68	28.23	0.19	0.68
	ESS	0.38	0.26	0.51	0.48	0.18	0.48	0.59	0.14	0.48	0.80	0.22	0.48	0.70	0.12	0.49
	EST	7.23E-04	0.25	0.47	6.98E−04	0.20	0.39	9.58E−04	0.03	0.40	1.06E−03	0.18	0.36	1.91E−03	0.03	0.18
	ESR	0.47	0.33	0.56	0.59	0.27	0.50	1.10	0.07	0.32	0.93	0.19	0.39	1.48	0.08	0.22
	YR	4.09	0.29	0.51	3.67	0.46	0.74	4.72	0.21	0.56	4.95	0.17	0.66	6.29	0.22	0.58
	YC	1.66	0.12	0.47	0.68	0.22	0.47	1.69	0.18	0.41	2.56	0.18	0.62	2.76	0.19	0.62
	HU	91.22	0.16	0.18	47.12	0.29	0.57	91.35	0.20	0.42	142.30	0.27	0.40	174.29	0.23	0.53
Multivariate model	ESI	7.53	0.27	0.42	8.49	0.24	0.47	10.97	0.14	0.42	12.83	0.26	0.50	15.21	0.24	0.48
	ESC	43.86	0.44	0.65	35.98	0.42	0.60	36.35	0.41	0.60	31.01	0.24	0.70	30.22	0.26	0.71
	ESS	0.39	0.26	0.51	0.48	0.17	0.47	0.60	0.17	0.48	0.80	0.19	0.48	0.70	0.13	0.50
	EST	7.22E-04	0.25	0.47	7.24E−04	0.23	0.41	9.75E−04	0.13	0.42	1.05E−03	0.16	0.36	1.93E−03	0.07	0.18
	ESR	0.47	0.31	0.56	0.58	0.27	0.48	1.11	0.10	0.32	0.94	0.18	0.38	1.49	0.11	0.23
	YR	4.32	0.36	0.52	3.73	0.45	0.74	4.86	0.28	0.58	4.89	0.16	0.65	6.28	0.27	0.58
	YC	1.61	0.12	0.44	0.69	0.18	0.48	1.77	0.18	0.43	2.58	0.21	0.62	2.74	0.20	0.61
	HU	90.43	0.14	0.18	46.13	0.34	0.56	90.16	0.22	0.41	139.69	0.26	0.39	171.70	0.23	0.51

With the univariate model, standard errors ranged from 0.04 to 0.09 for heritabilities, and from 0.02 to 0.03 for repeatabilities. With the multivariate model, standard errors ranged from 0.03 to 0.11 for heritabilities, and from 0.01 to 0.03 for repeatabilities
ESI egg shape index, ESC eggshell colour, ESS eggshell strength, EST eggshell thickness, ESR eggshell ratio, YR yolk ratio, YC yolk colour, HU Haugh unit, \({\sigma }_{p}^{2}\) phenotypic variance, h² heritability estimate with standard errors in parentheses, r repeatability estimate with standard errors in parentheses

ISSN: 1297-9686