The pattern of genetic and environmental variation in relation to ageing in laying hens

Engström, Göran; Liljedahl, LE; Wilhelmson, Martin; Johansson, Kjell

doi:10.1186/1297-9686-24-3-265

Cited by 13 publications

(2 citation statements)

References 10 publications

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“…However, some authors reported that model 1 without or with negligible maternal effects was suitable for egg production traits [ 8 , 35 , 36 ], contrary to the present study. A comprehensive review of the literature revealed that additive genetic effect increased and maternal effects decreased with age for production traits [ 37 – 39 ].…”

Section: Discussionmentioning

confidence: 99%

Analysis of (co) variance components and estimation of breeding value of growth and production traits in Dahlem Red chicken using pedigree relationship in an animal model

et al. 2021

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Variance and covariance components of growth and production traits were analyzed employing REML animal model to assess the Dahlem Red (PD-3) chicken population for direct additive genetic, maternal effects and to estimate the estimated breeding value (EBV), genetic parameters, genetic trends and rate of inbreeding (ΔF) utilizing seven generation’s data. The generation and hatch had significant (P≤0.01) effect on the body weight at 0 day (BW0), 2 (BW2), 4 (BW4) and 6 weeks (BW6) and shank length at six weeks of age (SL6). The average least squares means (LSM) for BW6 and SL6 were 273.93±0.62 g and 53.97±0.05 mm, respectively. All the production traits were significantly (P≤0.01) influenced by generation and hatch. The average LSM for age at sexual maturity (ASM), egg production up to 40 weeks (EP40) and egg mass up to 40 weeks (EM40) were 168.82±0.25 d, 72.60±0.41 eggs and 4.21±0.07 kg, respectively. Model 5 with additive direct, maternal genetic, maternal permanent environmental and residual variance components was the best for BW0, BW2 and BW4 based on the AIC values obtained in WOMBAT. Model 4 was the best model for BW6, SL6, ASM, EP40 and EM40 with additive direct, maternal permanent environmental and residual variance components. Maternal effects were higher during early age, decreased with age, and remained present until 20 weeks of age. The heritability (h2) estimates were low to moderate in magnitude for all the growth traits and ranged from 0.02±0.03 to 0.19±0.03. The maternal heritability was high at hatch (0.35±0.06), decreased gradually until 4th week (0.02±0.01) and ceased afterwards. The heritabilities of EP40 (0.11±0.03) and EM40 (0.12±0.04) were low. The direct additive genetic correlations (ra) between BW2, BW4, BW6 and SL6 were high and positive (P≤ 0.05). The additive genetic and maternal permanent environmental correlation between EP40 and EM40 were high and positive (P≤ 0.05). The EBV of EM40 was significant (P≤ 0.05) with 0.48 kg/generation in PD-3 chicken at the end of the seventh generation. The EBV of EP40 showed an increasing trend with a genetic gain of 1.87 eggs per generation. The average inbreeding coefficient of the population was 0.019 and average ΔF was 0.007 over the last seven generations of selection. The EBV trends for primary and associated traits showed linear trends in the desired direction and negligible inbreeding.

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Section: Discussionmentioning

confidence: 99%

Analysis of (co) variance components and estimation of breeding value of growth and production traits in Dahlem Red chicken using pedigree relationship in an animal model

et al. 2021

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“…The direct additive effects model without any maternal effects was suitable for egg production (Ghorbani et al., 2012; Le Bihan‐Duval et al., 1998; Norris & Ngambi, 2006), which was true in the present study also. A comprehensive review of the literature revealed that additive genetic variation increased with age for egg production and egg weight (Engstrom et al., 1992; Ledur et al., 2003; Niknafs et al., 2012). However, some authors reported maternal effects in addition to the direct additive effects for the egg production and egg weight (Jasouri et al., 2017; Misztal & Besbes, 2000; Yousefi et al., 2013).…”

Section: Discussionmentioning

confidence: 99%

Estimation of breeding value, genetic parameters and maternal effects of economic traits in rural male parent line chicken using pedigree relationships in an animal model

Rajkumar

Prince

Haunshi

et al. 2020

J Animal Breeding Genetics

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Breeding value (BV), genetic parameters and additive genetic, and maternal effects were evaluated on growth and production traits utilizing data from eight generations employing animal model in a rural male parent line (PD‐6) chicken at ICAR‐Directorate of Poultry Research, Hyderabad, India. The least squares means (LSM) for body weight (BW) and shank length (SL) up to 6 weeks of age varied significantly (p ≤ .01) among the generations and hatches. BW increased significantly (p ≤ .01) over the generations and decreased with the hatches. Sex also had a significant effect on BW and shank length except for BW at 0 day (BW0). LSM for BW (BW6) and Shank length (SL6) at 6 weeks of age were 598.84 ± 0.79 g and 74.57 ± 0.04 mm, respectively. Males recorded significantly (p ≤ .01) higher BWs and shank length. All the production traits were significantly (p ≤ .01) influenced by the generation effect. The overall LSM for age at sexual maturity (ASM), egg production at 40 weeks (EP40) and egg weight at 40 weeks (EW40) were 164.93 ± 0.23 days, 74.66 ± 0.40 eggs and 54.79 ± 0.08 g, respectively. Model 3 with additive, maternal permanent environmental and residual effects was the appropriate model for BW2, BW4, BW6, SL4 and SL6, whereas Model 4 with maternal effects was the best for BW0. The heritability estimates for BW6 and SL6 were 0.22 ± 0.02 and 0.18 ± 0.02, respectively. Model 1 with additive direct and residual effects was the best appropriate model for all the production traits. The heritability estimates of EP40 and EW40 were 0.16 ± 0.04 and 0.34 ± 0.05, respectively. BW and shank length were highly correlated with significant (p ≤ .05) positive association from different components. The correlation coefficient from direct additive component between egg production and BW40 was negative, while it was positive with less magnitude between egg production and BW20. The egg production and egg weights had a negative association at different ages. BV of SL6, the primary trait of selection, was significant (p ≤ .05) across the generations and increased linearly with an average genetic gain of 1.05 mm per generation. BV of BW6 was also significant (p ≤ .05) and increased linearly as correlated response with an average genetic response of 22.34 g per generation. BV of EP40 showed an increasing trend with a genetic gain of 0.02 eggs per generation. The EW 40 also increased linearly with an average genetic gain of 0.06 g. The average inbreeding coefficient of the population was 0.015. The study concluded that the population was in ideal status with a linearly increasing trend of average BV with negligible inbreeding over the eight generations of selection.

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Estimation of genetic parameters for body weight and egg production traits in Mazandaran native chicken

Niknafs

Nejati‐Javaremi

Mehrabani-Yeganeh

et al. 2012

Trop Anim Health Prod

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Native chicken breeding station of Mazandaran was established in 1988 with two main objectives: genetic improvement through selection programs and dissemination of indigenous Mazandarani birds. (Co)variance components and genetic parameters for economically important traits were estimated using (bi) univariate animal models with ASREML procedure in Mazandarani native chicken. The data were from 18 generations of selection (1988-2009). Heritability estimates for body weight at different ages [at hatch (bw1), 8 (bw8), 12 (bw12) weeks of ages and sex maturation (wsm)] ranged from 0.24 ± 0.00 to 0.47 ± 0.01. Heritability for reproductive traits including age at sex maturation (asm); egg number (en); weight of first egg (ew1); average egg weight at 28 (ew28), 30 (ew30), and 32 (ew32) weeks of age; their averages (av); average egg weight for the first 12 weeks of production (ew12); egg mass (em); and egg intensity (eint) varied from 0.16 ± 0.01 to 0.43 ± 0.01. Generally, the magnitudes of heritability for the investigated traits were moderate. However, egg production traits showed smaller heritability compared with growth traits. Genetic correlations among egg weight at different ages were mostly higher than 0.8. On the one hand, body weight at different ages showed positive and relatively moderate genetic correlations with egg weight traits (ew1, ew28, ew30, ew32, ew12, and av) and varied from 0.30 ± 0.03 to 0.59 ± 0.02. On the other hand, low negative genetic correlations were obtained between body weight traits (bw1, bw8, bw12, and wsm) and egg number (en). Also, there is low negative genetic correlation (-24 ± 0.04 to -29 ± 0.05) between egg number and egg weight. Therefore, during simultaneous selection process for both growth and egg production traits, probable reduction in egg production due to low reduction in egg number may be compensated by increases in egg weight.

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The pattern of genetic and environmental variation in relation to ageing in laying hens

Cited by 13 publications

References 10 publications

Analysis of (co) variance components and estimation of breeding value of growth and production traits in Dahlem Red chicken using pedigree relationship in an animal model

Analysis of (co) variance components and estimation of breeding value of growth and production traits in Dahlem Red chicken using pedigree relationship in an animal model

Estimation of breeding value, genetic parameters and maternal effects of economic traits in rural male parent line chicken using pedigree relationships in an animal model

Estimation of genetic parameters for body weight and egg production traits in Mazandaran native chicken

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