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

This study estimated the genetic parameters for reproductive and performance traits and determined which ones can be used as selection criteria for egg production in laying hens using the Bayesian inference. The data of 1894 animals from three generations of White Leghorn laying hens were analyzed for fertility (FERT), hatchability (HATC), and birth rate measurements at 60 weeks of age (BIRTH), body weight at 16 and 60 weeks of age (BW16 and BW60), age at sexual maturity (ASM), egg height/width ratio, weight, and density at 28, 36, and 40 weeks of age (RHW28, RHW36, RHW40, WEGG28, WEGG36, WEGG40, DENS28, DENS36, and DENS40, respectively) traits. The genetic parameters were estimated by the Bayesian inference method of multi-trait animal model. The model included the additive and residual genetic random effects and the fixed effects of generation. The a posteriori mean distributions of the heritability estimates for reproductive traits ranged from 0.14 ± 0.003 (HATC) to 0.22 ± 0.005 (FERT) and performance from 0.07 ± 0.001 (RHW28) to 0.42 ± 0.001 (WEGG40). The a posteriori mean distributions of the genetic correlation between reproductive traits ranged from 0.18 ± 0.026 (FERT and HACT) to 0.79 ± 0.007 (FERT and BIRTH) and those related to performance ranged from –0.49 ± 0.001 (WEGG36 and DENS36) to 0.75 ± 0.003 (DENS28 and DENS36). Reproductive and performance traits showed enough additive genetic variability to respond to selection, except for RHW28. This trait alone would have little impact on the genetic gain because environmental factors would have a higher impact compared to those from the additive genetic factors. Based on the results of this study, the selection applied on the BIRTH trait can be indicated to improve FERT and HATC of eggs. Furthermore, the use of the WEGG40 could improve egg quality in this population.

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DOMINANCE AND EPISTASIS IN HETEROSIS OF WHITE LEGHORN STRAIN CROSSES

Canadian Journal of Animal Science ◽

10.4141/cjas87-070 ◽

1987 ◽

Vol 67 (3) ◽

pp. 663-680 ◽

Cited By ~ 20

Author(s):

R. W. FAIRFULL ◽

R. S. GOWE ◽

J. NAGAI

Keyword(s):

Body Weight ◽

Sexual Maturity ◽

Egg Production ◽

Significant Contribution ◽

Production Traits ◽

White Leghorn ◽

Cross Combination ◽

Commercial Strain ◽

Better Than

Four unrelated pure strains of White Leghorns including a grandparent strain from industry and 12 two-strain, 24 three-strain, 24 four-strain and 12 F2 strain crosses produced contemporaneously were used to examine the role of dominance and epistasis in heterosis. A control strain and a commercial strain were also included. For egg weight, the heterosis observed closely approximated that expected due to dominance alone. For sexual maturity and body weight, dominance was the major component of heterosis, but epistasis made a significant contribution — additive by additive (A × A) genetic effects for sexual maturity and 140-d body weight, and parental epistasis for mature body weight. Both dominance and epistasis played a significant role in heterosis for egg production traits. A × A, dominance by dominance (D × D) and additive by dominance (A × D) epistasis were all important for hen-housed egg production and hen-housed egg yield. For hen-day rate of egg production, A × A epistasis was significant only early in the laying year (to 273 d), A × D and D × D were significant to 385 d and in the full year (to 497 d); however, none (A × A, A × D and D × D) was significant near the end of lay (386–497 d). Overall heterosis estimates for full year egg production measured as hen-housed egg production to 497 d or hen-day rate from housing to 497 d clearly showed that on average two-strain crosses were superior to three-strain crosses which were superior to four-strain crosses which in turn exceeded the F2 crosses. Nevertheless, several three-strain crosses had performance for egg production that was equal to or better than the two-strain cross with the highest egg production. Thus, in commerce, where the level of egg production is of great economic importance, the testing and use of a specific three-way cross combination will usually result in a better commercial product. Key words: Heterosis, egg production genetics, epistasis, stocking rate, strain cross, White Leghorn

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Genetic parameters associated with characters effecting egg production in the domestic fowl. I. Heritability of total egg production during the pullet year

Australian Journal of Agricultural Research ◽

10.1071/ar9560625 ◽

1956 ◽

Vol 7 (6) ◽

pp. 625 ◽

Cited By ~ 1

Author(s):

BL Sheldon

Keyword(s):

Standard Error ◽

Domestic Fowl ◽

Egg Production ◽

Genetic Parameters ◽

Research Centre ◽

Narrow Sense ◽

White Leghorn ◽

Components Of Variance ◽

Production Index ◽

The Mean

Egg production records of White Leghorn pullets hatched a t the Poultry Research Centre, Werribee, Vic., during 1947 to 1950 inclusive have been analysed both on a hen-housed (Production Index) and a survivor basis. Estimates of heritability were obtained by two methods: (1) by the analysis of components of variance between families of full sibs and half-sibs; (2) by estimating the intra-sire regression of the mean performance of offspring on dam's performance. Heritability, in the narrow sense, of Production Index during the pullet year is shown to be 23-30 per cent. with a reasonably low standard error, while heritability of survivors' production is slightly lower but not significantly so. Possible reasons are advanced for the low estimates of heritability of survivors' production.

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Histomorphometric Bone Properties of Sexually Immature and Mature White Leghorn Hens with Evaluation of Fluorochrome Injection on Egg Production Traits

Poultry Science ◽

10.3382/ps.0721537 ◽

1993 ◽

Vol 72 (8) ◽

pp. 1537-1547 ◽

Cited By ~ 26

Author(s):

H.A. HUDSON ◽

W.M. BRITTON ◽

G.N. ROWLAND ◽

R.J. BUHR

Keyword(s):

Egg Production ◽

Production Traits ◽

White Leghorn ◽

Bone Properties

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Genetic studies on egg production traits in IWN and IWP strains of White Leghorn chicken

Indian Journal of Poultry Science ◽

10.5958/0974-8180.2018.00064.8 ◽

2018 ◽

Vol 53 (3) ◽

pp. 247

Author(s):

Snehal D. Patil ◽

F.P. Savaliya ◽

A.B. Patel ◽

H.I. Paleja ◽

R.S. Joshi ◽

...

Keyword(s):

Egg Production ◽

Production Traits ◽

White Leghorn ◽

Genetic Studies ◽

White Leghorn Chicken

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GENETIC AND PHENOTYPIC ASSOCIATIONS OF JUVENILE BODY WEIGHTS AND EGG PRODUCTION TRAITS IN TWO STRAINS OF RHODE ISLAND CHICKENS

Nigerian Journal of Animal Production ◽

10.51791/njap.v18i.1968 ◽

2021 ◽

Vol 18 ◽

pp. 66-70

Author(s):

O. O. ONI ◽

B. Y. ABUBAKAR ◽

S. O. OGUNDIPE

Keyword(s):

Body Weight ◽

Rhode Island ◽

Sexual Maturity ◽

Egg Production ◽

Genetic Parameters ◽

Laying Hens ◽

Genetic Correlations ◽

Selection Criterion ◽

Production Traits ◽

Body Weights

Data on body weight at 16 (WT16); 20 (WT20) weeks of age and at sexual maturity (WTSM) weight of first egg (WT1st), age at sexual maturity (ASM) and 120-d egg production (EN) were used to estimate genetic parameters in 636 hens of two strains of Rhode Island chikens. There were significant (P.01) differences between the two strains for all traits except for WTSM.The heritability estimates obtained ranged from 0.05 to 0.41 and 0.04 to 0.30 for strains 1 and 2 respectively. The genetic correlations obtained for the various traits were medium to high for the two strains. The phenotypic correlations were generally low but followed the same trend. The results indicate that selected stocks of the two strains would show improvements in egg production and age at sexual maturity if juvenile body weight (WT20) is employed as a selection criterion at housing for laying hens.

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Estimates of genetic parameters and cluster analyses for carcass and meat quality traits in birds

Pesquisa Agropecuária Brasileira ◽

10.1590/s0100-204x2017000300008 ◽

2017 ◽

Vol 52 (3) ◽

pp. 205-213 ◽

Cited By ~ 1

Author(s):

Adriane Molardi Bainy ◽

Rodrigo Pelicioni Savegnago ◽

Luara Afonso de Freitas ◽

Beatriz do Nascimento Nunes ◽

Jaqueline Oliveira Rosa ◽

...

Keyword(s):

Meat Quality ◽

Genetic Parameters ◽

Genetic Correlations ◽

Meat Production ◽

Quality Traits ◽

Production Traits ◽

Multiple Trait ◽

Breeding Values ◽

Cluster Analyses ◽

Meat Quality Traits

Abstract: The objective of this work was to estimate genetic parameters for bird carcass and meat quality traits, as well as to explore the genetic patterns of the breeding values of this population using cluster analyses. Data from 1,846 birds were used to estimate the genetic parameters of production and quality traits using the multiple-trait animal model, and cluster analyses were performed. The heritability estimates ranged from 0.08± 0.03 for meat pH measured 24 hours after slaughter to 0.85± 0.09 for body weight. The genetic correlations between production traits were high and positive. The genetic correlations between meat quality traits were low and were not informative due to the high standard errors (same magnitudes as those of the genetic correlations). The genetic correlations between meat production and quality traits were negative, except between production traits and meat lightness intensity. Based on breeding values (EBVs), the evaluated population can be divided into four groups through cluster analyses, and one group is suitable for selection because the birds presented EBVs above and around the average of the population, respectively, for production and quality traits. Therefore, it is possible to obtain genetic gains for production-related traits without decreasing meat quality.

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