scholarly journals Genetic parameters for growth of young beef bulls

2012 ◽  
Vol 55 (3) ◽  
pp. 245-254
Author(s):  
L. Vostrý ◽  
Z. Veselá ◽  
J. Přibyl
Keyword(s):  
Fixed Effects ◽  
Genetic Effect ◽  
Information Criterion ◽  
Ratio Test ◽  
Residual Variance ◽  
Multiple Trait ◽  
Environment Effect ◽  
Body Weights ◽  
Direct Genetic Effect ◽  
Maternal Heritability

Abstract. The average daily gains of young bulls on test stations (ADGT) were analysed for the most frequent breeds of beef cattle in the Czech Republic using a multiple-trait animal model. Body weights at birth (W0), at 120 days of age (W120) and at weaning at 210 days (WW) were considered in this model as pre-weaning growth. The tested models comprised some of the random effects: direct genetic effect, maternal genetic effect, permanent animal environment effect, permanent maternal environment effect, and some of the fixed effects: dam’s age, sex, herd-year-season, linear and quadratic regression on age at the beginning of the test. For optimization of the models Akaike information criterion (AIC), residual variance and likelihood ratio test were used. Coefficients of direct and maternal heritability across breeds of about 0.25 for W0, about 0.17 for W120, about 0.17 for WW and about 0.29 for ADGT were estimated by all models. All criteria selected models including the permanent animal environment effect, which was the most important effect in the model.

Genetic association between cows’ stayability to three years of age and juvenile growth traits in Canadian Angus herds

2005 ◽  
Vol 85 (2) ◽  
pp. 139-143 ◽  
Author(s):  
D. P. Rasali ◽  
G. H. Crow ◽  
J. N. B. Shrestha ◽  
A. D. Kennedy ◽  
A. Brûlé-Babel
Keyword(s):  
Fixed Effects ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Genetic Effect ◽  
Genetic Effects ◽  
Birth Season ◽  
Angus Cattle ◽  
Body Weights ◽  
Direct Genetic Effect ◽  
Maternal Heritability

Bivariate linear animal models were fit using MTDFREML programs for the analysis of cows’ stayability to 3 yr (STAY3, n = 1, 703) as a binary scored trait paired with body weights at birth (BW, n = 6,116), 205-d weaning (WW, n = 5,360,) and 1 yr of age (YW, n = 5250) in Angus cattle. For STAY3, the model included a fixed effect due to herd ×year of cow’s birth along with a random direct genetic effect. For each of BW, WW and YW, the model included fixed effects due to herd ×birth year, birth season, birth type, calf’s sex and the age of dam (as linear and quadratic covariates), while the random effects were direct and maternal genetic effects and permanent maternal environmental effects. Survival analysis revealed that the risk of cows, 10 yr or less in age, being culled from five Canadian Angus herds was highest between 2 and 3 yr of age. The direct heritability (h2) estimates for BW, WW and YW were 0.54, 0.73 and 0.47, respectively, and corresponding maternal heritability estimates were 0.14, 0.33 and 0.13, respectively. Furthermore, the direct h2 estimate for STAY3 from three bivariate analyses was 0.23–0.24. Estimates of direct-maternal genetic correlations of BW, WW and YW were -0.18, -0.70 and -0.39, respectively. The direct genetic correlations of STAY3 with BW, WW and YW were -0.15 to -0.09 indicating that selection for growth would have less detrimental influence on the stayability trait of cows. The correlations of direct genetic effects of STAY3 with maternal genetic effects of BW, WW and YW were between 0.20 and 0.25, indicating their favorable relationships as correlated traits. Key words: Stayability, growth traits, heritability, genetic correlations, beef cattle

scholarly journals Estimates of (co)variance function for growth to yearling in Horro sheep of Ethiopia using random regression model

2010 ◽  
Vol 53 (6) ◽  
pp. 689-700
Author(s):  
S. Abegaz ◽  
J. B. van Wyk ◽  
J. J. Olivier
Keyword(s):  
Fixed Effects ◽  
Model Comparison ◽  
Information Criterion ◽  
Coefficient Matrix ◽  
Random Regression ◽  
Ratio Test ◽  
Residual Variance ◽  
Genetic Covariance ◽  
Heritability Estimates ◽  
One Year

Abstract. Random regression analyses of weight data from birth to 396 days were done using 22 141 weight records of 1 951 Horro lambs. Six different models formed from three different orthogonal polynomial regressions (legendre scale)orders (quadratic, cubic, quartic) of fit for both additive genetic and animals’ permanent environmental effects, with assumption of either homogeneous or heterogeneous residual variance, were compared. Fixed effects of year and type of birth, sex and age of dam were fitted along with a fourth order polynomial. Both likelihood ratio test (LRT) and Akaike's Information Criterion (AIC) were used for model comparison. Model fit improved with increased order of polynomial and assumption of heterogeneity of residual variance. Components for additive genetic and permanent environmental (co)variance increased from 0.03 and 0.09 at birth to 23.8 and 37.6 at 396 days of age, respectively. The first three eigenvalues of the coefficient matrix of the additive genetic covariance accounted for about 98 % of the sum of all the eigenvalues. Heritability estimates have shown a declining and increasing trend at different parts of the trajectory, the lowest estimate being 0.14 for weight at birth while the highest being 0.36 for weight at about 390 days of age. Higher heritability estimates in previous uni- and bi-variate models and in the current study and also strong correlation with weight at early age makes weight at one year of age the most important trait to consider in improving productivity in Horro sheep.

scholarly journals Estimates of covariance functions for growth of Anglo-Nubian goats

2011 ◽  
Vol 40 (1) ◽  
pp. 106-114 ◽  
Author(s):  
José Ernandes Rufino de Sousa ◽  
Martinho de Almeida e Silva ◽  
José Lindenberg Rocha Sarmento ◽  
Wandrick Hauss de Sousa ◽  
Maria do Socorro Medeiros de Souza ◽  
...  
Keyword(s):  
Bayesian Information Criterion ◽  
Regression Models ◽  
Genetic Effect ◽  
Information Criterion ◽  
Random Regression ◽  
Additive Genetic Effect ◽  
Ratio Test ◽  
Residual Variance ◽  
Covariance Functions ◽  
Heritability Estimates

It was used 4,313 weight records from birth to 196 days of age from 946 Anglo-nubiana breed goats, progenies from 43 sires and 279 dams, controlled in the period from 1980 to 2005, with the objective of estimating covariance functions and genetic parameters of animals by using random regression models. It was evaluated 12 random regression models, with degrees ranging from 1 to 7 for direct additive genetic and maternal and animal permanent environment effect and residual variance adjusted by using animal age ordinary polynomial of third order. Models were compared by using likelihood ratio test and by Bayesian information criterion of Schwarz and Akaike information criterion. The model selected based on Bayesian information criterion was the one that considered the maternal and direct additive genetic effect adjusted by a quadratic polynomial and the animal permanent environmental effect adjusted by a cubic polynomial (M334). Heritability estimates for direct effect were lower in the beginning and at the end of the studied period and maternal heritability estimates were higher at 196 days of age in comparison to the other growth phases. Genetic correlation ranged from moderate to high and they decreased as the distance between ages increased. Higher efficiency in selection for weight can be obtained by considering weights close to weaning, which is a period when the highest estimates of genetic variance and heritability are obtained.

A note on heritability estimates for growth traits in male and female Romanov sheep

1993 ◽  
Vol 57 (2) ◽  
pp. 326-328 ◽  
Author(s):  
G. A. María ◽  
K. G. Boldman ◽  
L. D. van Vleck
Keyword(s):  
Animal Model ◽  
Birth Weight ◽  
Maximum Likelihood ◽  
Random Effects ◽  
Fixed Effects ◽  
Growth Traits ◽  
Genetic Effect ◽  
Male And Female ◽  
Males And Females ◽  
Direct Genetic Effect

A total of 1855 records were analysed using restricted maximum likelihood (REML) techniques to estimate heritabilities separately for males and females lambs on birth weight (BW), weaning weight (WW), 90-day weight (W90) and average daily gains birth to weaning (Cl) and weaning to 90 days (C2). An animal model including fixed effects of year × season, parity, litter size and rearing type; and random effects of direct genetic effect (h2D) and residual was applied. Estimates ofh2Dfor BWwere 048 (males) and 0·50 (females); for WW 0·35 (males) and 0·22 (females); for W90 0·21 (males) and 0·31 (females); for Cl 0·20 (males) and 0·25 (females); and for C2 0·18 (males) and 0·29 (females).

scholarly journals Selection of a suitable definition of environment for the estimation of genotype × environment interaction in the weaning weight of beef cattle

2008 ◽  
Vol 53 (No. 10) ◽  
pp. 407-417 ◽  
Author(s):  
L. Vostrý ◽  
J. Přibyl ◽  
V. Jakubec ◽  
Z. Veselá ◽  
I. Majzlík
Keyword(s):  
Beef Cattle ◽  
Evaluation Model ◽  
Economic Value ◽  
Information Criterion ◽  
Ratio Test ◽  
Residual Variance ◽  
Environment Interaction ◽  
Weaning Weight ◽  
Genotype Environment Interaction ◽  
And Performance

Genotype by environment interactions for weaning weight in beef cattle were tested using several definitions of environments. Four breeds of beef cattle (Hereford, Aberdeen Angus, Beef Simmental, and Charolais) were represented. The environments were defined according to five criteria: altitude, production areas, economic value of the land, less favourable areas, and performance levels of a breed within herds. Ten mixed models were compared including the effects of direct and maternal genetics, herd-year-season, maternal permanent environmental, breed, environment, genotype × environment interaction, sex of calf, and age of dam. The suitability of the models was tested by Akaike’s Information Criterion, likelihood ratio test, and magnitude of the residual variance. The most suitable definitions of environment were less favoured areas and herd levels of performance. Estimates of direct heritability ranged from 0.07 to 0.19. Genotype × environment interactions should be included in a genetic evaluation model for interbreed comparisons of beef cattle in the Czech Republic.

PSXI-9 Heterotic and breed effects in crossbred lambs

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 248-248
Author(s):  
Napoleon Vargas Jurado ◽  
Bret Taylor ◽  
David R Notter ◽  
Daniel Brown ◽  
Ronald M Lewis
Keyword(s):  
Maternal Effects ◽  
Growth Traits ◽  
Genetic Evaluation ◽  
Multiple Trait ◽  
Body Weights ◽  
Considerable Impact ◽  
Covariance Components ◽  
Heritability Estimates ◽  
Maternal Heritability ◽  
The U.S

Abstract Given its benefits on animal performance, crossbreeding is common commercially. Genetic evaluation of sheep in the U.S. is performed within breed type (terminal, maternal wool, range, hair). While incorporating crossbred records may improve assessment of purebreds, it requires accounting for heterotic and breed effects in the evaluation. The objectives were to i) determine the generalized effects of direct and maternal heterosis on growth traits of crossbred lambs, and ii) estimate covariance components for direct and maternal additive, and uncorrelated maternal environmental, effects among those traits. Data included body weights (BW) at birth (BN; n = 14395), pre-weaning (WN; n = 9298), weaning (WW; n = 9230), and post-weaning (PW; n = 1593). Mean (SD) BW were 5.3 (1.1), 22.2 (8.7), 39.1 (7.2), and 54.2 (8.7) kg for BN, WN, WW, and PW, respectively. Estimates of heterotic effects and covariance components were obtained using a multiple trait animal model. Genetic effects based on founders’ breeds were included, being significant. Estimates of direct heterosis were 3.04 ± 0.61, 2.62 ± 0.64, 3.99 ± 0.54, and 5.97 ± 0.86%, and estimates of maternal heterosis were 1.86 ± 0.87, 4.42 ± 0.79, 3.69 ± 0.66, and 3.77 ± 0.90%, for BN, WN, WW, and PW, respectively. Direct heritability estimates were 0.17 ± 0.02, 0.13 ± 0.02, 0.18 ± 0.02, and 0.47 ± 0.04 for BN, WN, WW, and PW, respectively. Additive maternal effects defined trivial variation in PW. For BN, WN, and WW, respectively, maternal heritability estimates were 0.17 ± 0.02, 0.10 ± 0.02, and 0.07 ± 0.02. Uncorrelated maternal effects defined little variation in any trait. Direct and maternal heterosis had considerable impact on growth traits, emphasizing the value of crossbreeding and the need to account for heterosis, in addition to breed effects, if crossbred lamb information is included in genetic evaluation.

scholarly journals Development of optimal genetic evaluations for teat and udder structure in Canadian Angus cattle

2019 ◽  
Vol 97 (11) ◽  
pp. 4445-4452 ◽  
Author(s):  
Kajal Devani ◽  
Tiago S Valente ◽  
John J Crowley ◽  
Karin Orsel
Keyword(s):  
Fixed Effects ◽  
Genetic Effect ◽  
Information Criteria ◽  
Breeding Value ◽  
Additive Genetic Effect ◽  
Multiple Trait ◽  
Angus Cattle ◽  
Genotypic Correlations ◽  
Genetic Evaluations ◽  
The Impact

Abstract Despite their heritability and influence on female productivity, there are currently no genetic evaluations for teat and udder structure in Canadian Angus cattle. The objective of this study was to develop optimal genetic evaluations for these traits in the Canadian Angus population. Guidelines recommended by Beef Improvement Federation (BIF) were used to score teat and udder structure in 1,735 Canadian Angus cows from 10 representative herds. Cows scored ranged in parity from 1 to 13; however, >70% of cows were parity ≤4. Scores ranged from 1 (large, bottle shaped) to 9 (very small) for teats and from 1 (very pendulous) to 9 (very tight) for udders. Consistent with parity distribution, >70% of teat and udder scores were ≥6. Teat and udder scores (TS9 and US9, respectively) were modeled using a multiple trait animal model with random effects of contemporary group (herd-year-season) and additive genetic effect, and fixed effects of breed, parity group, and days between calving and scoring. To test good versus poor structure, a binary classification of 1 or 2 (TS2, US2) [comprised of scores 1 to 5 = 1 (poor structure) and scores 6 to 9 = 2 (good structure)] was created. Further, to assess the impact of grouping less frequently observed poor scores, a 1 to 7 scale (TS7, US7) was created by combining teat and udder scores 1 to 3. Analyses for teat and udder scores on scales TS9, US9, TS7, US7, and TS2, US2 were compared. In addition, both threshold and linear animal models were used to estimate variance components for the traits. Data treatment and models were evaluated based on correlation of resulting estimated breeding value (EBV) with corrected phenotypes, Spearman’s rank correlation coefficient, average EBV accuracies (r), and deviance information criteria (DIC). TS9, US9 scales for teat and udder scores and linear models performed best. Estimates of heritability (SE) for teat and udder score were 0.32 (0.06) and 0.15 (0.04), respectively, indicating these traits were moderately heritable and that genetic improvement for teat and udder scores was possible. Estimates of phenotypic and genotypic correlations for teat and udder score were 0.46 (0.02) and 0.71 (0.09), respectively. Estimates of genotypic correlations with birth weight (BW), weaning weight (WW), and yearling weight (YW), ranged from −0.04 (0.10) to −0.20 (0.12), verifying the importance of selecting for improved teat and udder score as individual traits, alongside performance traits.

scholarly journals Genetic parameter of birth and weaning weights for Friesian calves by using an animal model

2005 ◽  
Vol 48 (3) ◽  
pp. 261-269 ◽  
Author(s):  
H. Atil ◽  
A. S. Khattab ◽  
L. Badawy
Keyword(s):  
Animal Model ◽  
Birth Weight ◽  
Fixed Effects ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Likelihood Method ◽  
Multiple Trait ◽  
Breeding Values ◽  
Heritability Estimates ◽  
Maternal Heritability

Abstract. Birth and weaning weights of 556 Friesian calves by 41 sires out of 318 different dams over a 11 years period were obtained from a herd of Friesian in Sakha Experimental Farm, Ministry of Agriculture, Egypt were used. The records were analyzed by Multiple Trait Likelihood Method (MTDFREML) by using a repeatability animal model (BOLDMAN et al., 1995). Convergence was attained after 699 iterations. The fixed effects included in the model were season and year of calving, parity and sex and the random effects were direct and maternal genetic, permanent maternal environmental and error. Direct heritability estimates for birth weight (BW) and weaning weight (WW) are 0.28 and 0.13, respectively, while, maternal heritability estimates for the same traits are 0.14 and 0.06, respectively. Repeatability estimates are 0.75 and 0.15 for BW and WW, respectively. Phenotypic and genetic correlations are 0.89 and 0.80, respectively. Estimates of calve breeding values ranged from −3.12 to 4.11 kg for BW and ranged from −4.10 to 5.11 kg for WW. Sire breeding values ranged from −3.40 to 2.99 kg for BW and ranged from −2.50 to 4.47 kg for WW. Dam breeding values ranged from −6.80 to 5.54 kg for BW and ranged from -6.10 to 6.39 kg for WW.

scholarly journals Estimation of genetic parameters for melanoma in the Old Kladruber horse

2012 ◽  
Vol 57 (No. 2) ◽  
pp. 75-82 ◽  
Author(s):  
L. Vostrý ◽  
B. Hofmanová ◽  
H. Vostrá Vydrová ◽  
J. Přibyl ◽  
I. Majzlík
Keyword(s):  
Animal Model ◽  
Genetic Variation ◽  
Correlation Coefficient ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
Rank Correlation ◽  
Genetic Effect ◽  
Pedigree Information ◽  
Direct Genetic Effect ◽  
Estimation Of Genetic Parameters

The aim of this study was to assess the prevalence of melanoma to investigate a possible genetic variation of this trait in the Old Kladruber horse. A total of 564 grey varieties of the Old Kladruber horse, 238 males and 326 females, with five generations of ancestors (n = 1245 animals) were analysed. Melanoma status was recorded for different stages. Three different analyses were conducted: a linear animal model (LM) with melanoma classified into five categories, threshold animal model (TM) with melanoma classified into five categories and threshold animal model (TMb) with melanoma classified into two categories (0 = absence, 1 = presence). All models included the fixed effects of year of evaluation, age, line, sex, greying level, random direct genetic effect, and the effect of animal’s permanent environment. Heritability for melanoma occurrence was estimated for LM – 0.09, for TM – 0.27, and for TMb – 0.11. The coefficient of repeatability was estimated for LM – 0.77, for TM – 0.90, and for TMb – 0.99. The values of the Pearson’s correlation coefficient and Spearmen’s rank correlation coefficient among breeding values estimated by LM, TM, and TMb models were from 0.82 to 0.88 and from 0.83 to 0.90, respectively, for data with pedigree information and from 0.77 to 0.84 and 0.77 to 0.88, respectively, for a subset of animals with measurements. Results suggest that additive genetic variation of melanoma occurrence in the Old Kladruber horse seems large enough to be exploited in a specific breeding programme.  

scholarly journals Multiple-trait, random regression, and compound symmetry models for analyzing multi-environment trials in maize breeding

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242705
Author(s):  
Igor Ferreira Coelho ◽  
Marco Antônio Peixoto ◽  
Jeniffer Santana Pinto Coelho Evangelista ◽  
Rodrigo Silva Alves ◽  
Suellen Sales ◽  
...  
Keyword(s):  
Information Criterion ◽  
Genetic Effects ◽  
Random Regression ◽  
Ratio Test ◽  
Environment Interaction ◽  
Maize Breeding ◽  
Multiple Trait ◽  
Data Set ◽  
Maize Hybrids ◽  
Compound Symmetry

An efficient and informative statistical method to analyze genotype-by-environment interaction (GxE) is needed in maize breeding programs. Thus, the objective of this study was to compare the effectiveness of multiple-trait models (MTM), random regression models (RRM), and compound symmetry models (CSM) in the analysis of multi-environment trials (MET) in maize breeding. For this, a data set with 84 maize hybrids evaluated across four environments for the trait grain yield (GY) was used. Variance components were estimated by restricted maximum likelihood (REML), and genetic values were predicted by best linear unbiased prediction (BLUP). The best fit MTM, RRM, and CSM were identified by the Akaike information criterion (AIC), and the significance of the genetic effects were tested using the likelihood ratio test (LRT). Genetic gains were predicted considering four selection intensities (5, 10, 15, and 20 hybrids). The selected MTM, RRM, and CSM models fit heterogeneous residuals. Moreover, for RRM the genetic effects were modeled by Legendre polynomials of order two. Genetic variability between maize hybrids were assessed for GY. In general, estimates of broad-sense heritability, selective accuracy, and predicted selection gains were slightly higher when obtained using MTM and RRM. Thus, considering the criterion of parsimony and the possibility of predicting genetic values of hybrids for untested environments, RRM is a preferential approach for analyzing MET in maize breeding.

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