Multivariate restricted maximum  likelihood estimation of genetic  parameters for production traits  in three selected turkey strains*

Chapuis, H.; Tixier-Boichard, M.; Delabrosse, Y.; Ducrocq, V.

doi:10.1051/gse:19960308

Cited by 8 publications

(11 citation statements)

References 24 publications

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“…As observed by Merritt [23] and Ayoub et al [2] in small groups of broilers and by Chapuis et al [7] in a large sample of data on turkeys, heritability appears to be higher for female body weight than for male body weight. Higher residual variance and lower additive genetic variance were observed for male traits.…”

Section: Genetic Parameters Of Growth Traits In Both Sexessupporting

confidence: 49%

Estimation of the genetic parameters of sexual dimorphism of body weight in 'label' chickens and Muscovy ducks

Mignon-Grasteau¹,

Beaumont²,

Poivey³

et al. 1998

Genet. Sel. Evol.

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Section: Genetic Parameters Of Growth Traits In Both Sexessupporting

confidence: 49%

Estimation of the genetic parameters of sexual dimorphism of body weight in 'label' chickens and Muscovy ducks

Mignon-Grasteau¹,

Beaumont²,

Poivey³

et al. 1998

Genet. Sel. Evol.

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“…Ayorinde and Olagbuyiro [2] also reported that clutch size varied from 1 to 12 eggs, and the highest frequency was 72.3% for a 1-3 egg clutch. The Box-Cox transformation of egg production traits resulted in increases in estimated heritability, which were reported by Ibe and Hill [20], Besbes et al [7] and Chapuis et al [13]. In the present study, the estimated heritability values were 0.15 ± 0.01 and 0.42 ± 0.02 for un-transformed and transformed variables, respectively.…”

Section: Data Distribution and Transformationsupporting

confidence: 68%

Estimation of genetic variability and selection response for clutch length in dwarf brown-egg layers carrying or not the naked neck gene

Chen

Tixier‐Boichard

2003

Genet. Sel. Evol.

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-In order to investigate the possibility of using the dwarf gene for egg production, two dwarf brown-egg laying lines were selected for 16 generations on average clutch length; one line (L1) was normally feathered and the other (L2) was homozygous for the naked neck gene NA. A control line from the same base population, dwarf and segregating for the NA gene, was maintained during the selection experiment under random mating. The average clutch length was normalized using a Box-Cox transformation. Genetic variability and selection response were estimated either with the mixed model methodology, or with the classical methods for calculating genetic gain, as the deviation from the control line, and the realized heritability, as the ratio of the selection response on cumulative selection differentials. Heritability of average clutch length was estimated to be 0.42 ± 0.02, with a multiple trait animal model, whereas the estimates of the realized heritability were lower, being 0.28 and 0.22 in lines L1 and L2, respectively. REML estimates of heritability were found to decline with generations of selection, suggesting a departure from the infinitesimal model, either because a limited number of genes was involved, or their frequencies were changed. The yearly genetic gains in average clutch length, after normalization, were estimated to be 0.37 ± 0.02 and 0.33 ± 0.04 with the classical methods, 0.46 ± 0.02 and 0.43 ± 0.01 with animal model methodology, for lines L1 and L2 respectively, which represented about 30% of the genetic standard deviation on the transformed scale. Selection response appeared to be faster in line L2, homozygous for the NA gene, but the final cumulated selection response for clutch length was not different between the L1 and L2 lines at generation 16. dwarf chicken / naked neck gene / clutch length / genetic variability / selection response

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“…The relative influence of maternal effects is generally moderate in poultry. In turkeys, environmental maternal effects represented , 5.2% to 8% of the total variance of BW at 12 and 16 weeks of age, depending on the strains tested (Chapuis et al, 1996). This result, in addition to the particularities of our pedigree (65% of the 334 dams were of unknown parents), may explain why we were not able to evidence any maternal effects.…”

Section: Resultsmentioning

confidence: 75%

“…Case et al (2010) reported values of 0.35 6 0.02 for the heritability of BW at 15 weeks with the bivariate method. Chapuis et al (1996) reported heritability estimates of 0.77 for female BW and 0.68 for male BW at 16 weeks of age. In the study by Nestor et al (2006), the realised heritability of 16-week BW was 0.202, 0.130 and 0.166 for males, females and both sexes, respectively, during the last generations of selection.…”

Section: Heritabilitymentioning

confidence: 99%

Estimates of the genetic parameters of turkey body weight using random regression analysis

Rafat

Namavar

Shodja

et al. 2011

Animal

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Random regression (RR) analysis has been recommended to estimate the genetic parameters of longitudinal data. The objective of this study was to evaluate the growth of turkeys using RR models. Data were collected from 957 turkeys and included 15 478 individual body weight recorded during the first week of life and between weeks 2 and 32 by 2-week intervals. To take into account the repeated measurements of weight for each animal, a specific overall growth curve was modelled using a cubic smoothing spline. Animal deviation to this curve was also modelled using an RR function. All data were analysed with the ASReml package. The results showed an increase in heritability estimates over the trajectory and peaked at 0.60 around 20 to 32 weeks of age. Genetic correlations showed that turkeys could be selected at earlier time points, at 12 weeks of age, in order to increase the growth rate. In general, genetic correlation estimates were higher among adjacent ages, decreasing markedly with the increase of distance between ages. Negative genetic correlations were observed between ages.

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Multivariate restricted maximum likelihood estimation of genetic parameters for production traits in three selected turkey strains*

Cited by 8 publications

References 24 publications

Estimation of the genetic parameters of sexual dimorphism of body weight in 'label' chickens and Muscovy ducks

Estimation of the genetic parameters of sexual dimorphism of body weight in 'label' chickens and Muscovy ducks

Estimation of genetic variability and selection response for clutch length in dwarf brown-egg layers carrying or not the naked neck gene

Estimates of the genetic parameters of turkey body weight using random regression analysis

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