Genetic parameters for egg and related characteristics of white Leghorn hens in a subtropical environment

Abstract

Estimates of heritability and phenotypic and genetic correlations between egg number, weight, specific gravity, mass, and estimated shell weight were obtained, along with phenotypic and genetic correlations of specific gravity and weight with body weight, weight change, metabolizable energy intake, residual feed consumption, and weight and age at sexual maturity. Data were from 350 White Leghorn hens by 50 sires and 175 dams. Heritabilities of the egg traits ranged from 0.20 to 0.55, increasing with age of bird from 26 to 54 weeks of age. Their standard errors ranged from 0.07 (all data) to 0.17 (26 to 29 weeks). Phenotypic correlations ranged from 0.80 to -0.13, and genetic correlations from 0.91 to -0.27, depending on egg trait. The highest phenotypic and genetic correlations were between egg number and mass. Genetic correlations for specific gravity and estimated shell weight were, with body weight, -0.02 and 0.56; weight change, 0.29 and 0.44; daily metabolizable energy intake, -0.10 and 0.33; residual consumption, -0.16 and 0.11; age at sexual maturity, -0.61 and -0.46, and weight at sexual maturity, 0.02 and 0.63. Results should contribute to the design of efficient selection programs for economically important traits in hens.

Estimates of genetic parameters, and cluster and principal components analyses of breeding values related to egg production traits in a White Leghorn population

“…The median heritability estimates for EP1730 were higher when compared with heritability estimates of other egg production periods, and they were similar to those related by Sabri et al (1999) andFrancesch et al (1997) of 0.27 ± 0.17 and 0.20 ± 0.06 to 0.33 ± 0.05, respectively. Munari et al (1992) found heritability estimates of 0.33 ± 0.04 for egg production rate from 18 to 40 wk, 0.31 ± 0.04 from 18 to 50 wk, 0.40 ± 0.04 from 18 to 70 wk, 0.26 ± 0.04 from 40 to 50 wk, 0.38 ± 0.04 from 50 to 70 wk, and 0.40 ± 0.04 from 40 to 70 wk of age.…”

“…Francesch et al (1997) found heritability estimates for egg weight at 39 wk of age ranging from 0.48 ± 0.05 to 0.59 ± 0.06 in 3 layer breeds. Sabri et al (1999) obtained heritability estimates of 0.46 ± 0.17 for egg weight between 26 and 30 wk of laying and of 0.50 ± 0.19 for egg weight between 50 and 54 wk of laying. Ledur et al (1998) reported heritability estimates of 0.44 ± 0.05 (female fullsister intraclass correlation) and 0.37 ± 0.08 (female half-sister intraclass correlation) for egg weight at 36 wk of age for the same strain.…”

Estimates of (co)variance components for production and reproduction traits with different models in Fars native fowls

“…We found that only direct genetic effect influenced on egg number; thus, h 2 for this trait estimated as 0.20, and this value was significantly different from zero. Our estimate was in the range of other published literature (Lwelamira et al, 2009;Nurgiartiningsih et al, 2004;Sabri et al, 1999).…”

Egg specific gravity in improvement of hatchability in laying hens

“…This value was lower than that obtained by Sabri et al (1999), where heritability ranged from 0.23 to 0.45, depending on the egg-laying period. The investigations conducted by other authors involved shell resistance (Nirasawa et al, 1998;Besbes and Gibson, 1999), correlated with ESG.…”