scholarly journals Estimation of inbreeding effect on conception in Czech Holstein

2019 ◽  
Vol 64 (No. 7) ◽  
pp. 309-316
Author(s):  
Michala Hofmannová ◽  
Josef Přibyl ◽  
Emil Krupa ◽  
Petr Pešek
Keyword(s):  
Genetic Parameters ◽  
Negative Impact ◽  
Additive Genetic Variance ◽  
Random Effect ◽  
Inbreeding Coefficient ◽  
Conception Rate ◽  
Breeding Value ◽  
Breeding Values ◽  
Binary Model ◽  
Animal Model Blup

The influence of calculated inbreeding coefficients on the conception of heifers and cows was analysed by a two-trait binary model for conceived/not conceived after each insemination on 677 234 Czech Holstein cows and heifers with 3 248 299 insemination records as the covariable in a statistical model. The data between 1996 and 2014 were analysed. Various effects and their statistical influence on traits were tested by a generalized linear model. Consequently, genetic parameters were estimated by the Gibbs sampling method and used in predicting breeding values using the best linear unbiased prediction by animal model (BLUP-AM). The mean for the conception rate of cows averaged over lactations was 33.7% and for heifers it reached 53.8%. Average inbreeding coefficient increased from 1% in 1996 to almost 5% by 2013 and was in the range of 0–45%. The rate of inbreeding per generation was 0.20%. Although the effect of inbreeding was statistically significant (P = 0.05) for both traits, the proportion of variability explained by the models was relatively low. Estimated genetic parameters were low for both traits. Coefficient of heritability was 2.00% and 1.30% for cows and heifers, respectively, whereas coefficients of repeatability reached 6.09% and 7.08% for cows and heifers, respectively. The random effect of the permanent environment (PE) reached higher values than the additive genetic variance (G) and explained 5.67% and 4.09% of variability for cows and heifers, respectively. A negative impact of inbreeding on heifer and cow conception was observed, whereby every 10% increase in inbreeding coefficient resulted in a conception decline by 2.23%. Calculated Spearman’s rank correlation coefficient between estimated breeding values considering and not considering the effect of inbreeding was close to one. Presented results indicate that inbreeding has a negligible influence on the breeding values of conception. The results also indicate that it is not necessary to include inbreeding coefficient in the routine breeding value evaluation of conception rate of heifers and cows. On the other hand, monitoring of inbreeding is necessary to avoid an increase of its rate.

scholarly journals A note on genetic parameters and accuracy of estimated breeding values in honey bees

2019 ◽  
Vol 51 (1) ◽  
Author(s):  
Evert W. Brascamp ◽  
Piter Bijma
Keyword(s):  
Honey Bees ◽  
Variance Components ◽  
Genetic Parameters ◽  
Additive Genetic Variance ◽  
Breeding Value ◽  
Phenotypic Variance ◽  
Breeding Values ◽  
Estimated Breeding Values ◽  
Additive Genetic Relationship ◽  
The Relationship

Abstract Background In honey bees, observations are usually made on colonies. The phenotype of a colony is affected by the average breeding value for the worker effect of the thousands of workers in the colony (the worker group) and by the breeding value for the queen effect of the queen of the colony. Because the worker group consists of multiple individuals, interpretation of the variance components and heritabilities of phenotypes observed on the colony and of the accuracy of selection is not straightforward. The additive genetic variance among worker groups depends on the additive genetic relationship between the drone-producing queens (DPQ) that produce the drones that mate with the queen. Results Here, we clarify how the relatedness between DPQ affects phenotypic variance, heritability and accuracy of the estimated breeding values of replacement queens. Second, we use simulation to investigate the effect of assumptions about the relatedness between DPQ in the base population on estimates of genetic parameters. Relatedness between DPQ in the base generation may differ considerably between populations because of their history. Conclusions Our results show that estimates of (co)variance components and derived genetic parameters were seriously biased (25% too high or too low) when assumptions on the relationship between DPQ in the statistical analysis did not agree with reality.

scholarly journals Estimation of direct and maternal genetic parameters for weaning weight in Hungarian Simmental cattle

2021 ◽  
pp. 17-22
Author(s):  
Afees Abiola Ajasa ◽  
Imre Füller ◽  
Barnabás Vágó ◽  
István Komlósi ◽  
János Posta
Keyword(s):  
Fixed Effects ◽  
Genetic Parameters ◽  
Additive Genetic Variance ◽  
Random Effect ◽  
Ratio Test ◽  
Genetic Covariance ◽  
Weaning Weight ◽  
Simmental Cattle ◽  
Estimate Variance ◽  
Best Fit

The aim of the current research was to estimate variance components and genetic parameters of weaning weight in Hungarian Simmental cattle. Weaning weight records were obtained from the Association of Hungarian Simmental Breeders. The dataset comprised of 44,278 animals born from 1975 to 2020. The data was analyzed using the restricted maximum likelihood methodology of the Wombat software. We fitted a total of six models to the weaning weight data of Hungarian Simmental cattle. Models ranged from a simple model with animals as the only random effect to a model that had maternal environmental effects as additional random effects as well as direct maternal genetic covariance. Fixed effects in the model comprised of herd, birth year, calving order and sex. Likelihood ratio test was used to determine the best fit model for the data. Results indicated that allowing for direct-maternal genetic covariance increases the direct and maternal effect dramatically. The best fit model had direct and maternal genetic effects as the only random effect with non-zero direct-maternal genetic correlation. Direct heritability, maternal heritability and direct maternal correlation of the best fit model was 0.57, 0.16 and -0.78 respectively. The result indicates that problem of (co-)sampling variation occurs when attempting to partition additive genetic variance into direct and maternal components.

Selection of parents and estimation of genetic parameters using BLUP and molecular methods for lentil (Lens culinaris Medik.) breeding program in Argentina

2019 ◽  
Vol 56 (1) ◽  
pp. 12-25
Author(s):  
Carolina Bermejo ◽  
Federico Cazzola ◽  
Fernando Maglia ◽  
Enrique Cointry
Keyword(s):  
Quantitative Traits ◽  
Genetic Parameters ◽  
Selection Process ◽  
Recombinant Inbred Lines ◽  
Correlation Coefficients ◽  
Cost Effective ◽  
Molecular Data ◽  
Breeding Value ◽  
Breeding Values ◽  
High Yields

AbstractThe most important objective of lentil breeding programs is to develop new genotypes that are genetically more productive. Besides, it is necessary that the varieties obtained have short flowering cycles to allow the later sowing of summer crops. Selection is based through phenotypic means; however, we argue it should be based on genetic or breeding values because quantitative traits are often influenced by environments and genotype–environment interactions. The objectives of this study were to: (i) identify genotypes with the highest merit; (ii) estimate genetic parameters to know the genetic control of morphological traits in macrosperma and microsperma lentil types using best linear unbiased prediction (BLUP). Twenty-five recombinant inbred lines (RILs) from six F4 families selected on the basis of precocity and high yields were tested in four environments for important quantitative traits. The analysis of variance showed significant differences between genotypes, environments, and genotype–environment interactions for all the traits. Seven macrosperma- and two microsperma-type RILs were selected. Based on average ranking from breeding values and molecular data obtained with sequence-related amplified polymorphism (SRAP), the same genotypes were selected. Genotypic coefficients of variation, heritability across and by environment, and genetic correlation coefficients using BLUP were obtained. According to our results BLUP could replace molecular analysis methods because the selection process was simpler, more cost-effective, and more accurate. The breeding value of parents would give a better ranking of their genetic value than would their phenotypic value; therefore, the selection efficiency would be enhanced and the genetic gain would be more predictable. The selected genotypes could become potential commercial varieties or be used as parental lines in future hybridization programs.

Potential biases of incomplete linear models in heritability estimation and breeding value prediction

1999 ◽  
Vol 29 (6) ◽  
pp. 724-736 ◽  
Author(s):  
P X Lu ◽  
D A Huber ◽  
T L White
Keyword(s):  
Genetic Variance ◽  
Linear Models ◽  
Additive Genetic Variance ◽  
Genetic Effect ◽  
Breeding Value ◽  
Additive Genetic Effect ◽  
Unbalanced Data ◽  
Breeding Values ◽  
Incomplete Model ◽  
Heritability Estimation

Potential biases associated with incomplete linear models in the estimation of heritability and the prediction of breeding values have been investigated. Results indicate that estimates of additive genetic variance and heritability as well as predicted parental breeding values from incomplete models will inevitably be biased as long as the true variance components of ignored effects are not zero. While models ignoring the interaction effect of males and females (SCA) × environment (E) interaction downwardly biased the estimates of additive genetic variance and heritability, models ignoring SCA and (or) the additive genetic effect (GCA) × E interaction yielded upward biases. The magnitudes of biases are functions of population genetic architecture, mating design, and field experimental design and can be precisely assessed with formulae derived for balanced data. Numerical simulations using unbalanced data of different mating and field experimental designs suggest that the formulae from balanced data can be used to approximate the minimum biases associated with unbalanced data. Because of the magnitudes of biases for some typical forest genetic scenarios, it is suggested that models ignoring SCA and (or) GCA × E should be avoided when the numbers of test sites and crosses per parent are small. However, incomplete model ignoring SCA × E interaction may be used to reduce computational demand with only negligible consequences.

Estimates of genetic parameters for growth traits of Gobra cattle

1998 ◽  
Vol 66 (2) ◽  
pp. 349-355 ◽  
Author(s):  
M. Diop ◽  
L. D. Van Vleck
Keyword(s):  
Animal Models ◽  
Maternal Effects ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Random Effect ◽  
Random Effect Model ◽  
Genetic Effects ◽  
Breeding Value ◽  
Effect Model ◽  
Additive Genetic Effects

AbstractEstimates of (co)variance components and genetic parameters were obtained for birth (no. = 3909), weaning (no. = 3425), yearling (no. = 2763), and final weight (no. = 2142) for Gobra cattle at the Centre de Recherches Zootechniques de Dahra (Senegal), using single trait animal models. Data were analysed by restricted maximum likelihood. Four different animal models were fitted for each trait. Model 1 considered the animal as the only random effect. Model 2 included in addition to the additive direct effect of the animal, the environmental effect due to the dam. Model 3 added the maternal additive genetic effects and allowed a covariance between the direct and maternal genetic effects. Model 4 fitted both maternal genetic and permanent environmental effects. Inclusion of both types of maternal effects (genetic and environmental) provided a better fit for birth and weaning weights than models with one maternal effect only. For yearling and final weights, the improvement was not significant. Important maternal effects werefound for all traits. Estimates of direct heritabilities were substantially higher when maternal effects were ignored. Estimates of direct and maternal heritabilities with model 4 were 0·07 (s.e. 0·03) and 0·04 (s.e. 0·02), 0·20 (s.e. 0·05) and 0·21 (s.e. 0.05), 0·24 (s.e. 0·07) and 0·21 (s.e. 0·06), and 0·14 (s.e. 0·06) and 0.16 (s.e. 0·06) for birth, weaning, yearling and final weights, respectively. Correlations between direct and maternal genetic effects were negative for all traits, and large for weaning and yearling weights with estimates of -0·61 (s.e. 0·33) and -0·50 (s.e. 0·31), respectively. There was a significant positive linear phenotypic trend for weaning and yearling weights. Linear trends for additive direct and maternal breeding values were not significant for any trait except maternal breeding value for yearling weight.

scholarly journals Evaluation of Breeding Value Based on Scores Achieved in the Polish Championships for Young Horses

2015 ◽  
Vol 15 (4) ◽  
pp. 879-887
Author(s):  
Tomasz Próchniak ◽  
Iwona Rozempolska-Rucińska ◽  
Grzegorz Zięba ◽  
Marek Łukaszewicz
Keyword(s):  
Genetic Improvement ◽  
Genetic Parameters ◽  
Performance Test ◽  
Breeding Value ◽  
Genetic Trend ◽  
Breeding Values ◽  
Physical Traits ◽  
Young Horses ◽  
Show Jumping ◽  
Detailed Picture

Abstract Genetic improvement of show jumping horses is problematic, given the multitude of physical traits that determine sport usability and the specific mental predispositions required during training and competitions. The Polish Championships for Young Horses (PCYH) provide an opportunity to evaluate usability traits in Polish horses, which, however, is not a basis for evaluation of the breeding value. The aim of the study was to propose a model for evaluation of the breeding value of horses taking part in the Championships. In total, 1232 starts of 894 4-, 5-, 6-, and 7-year-old horses were analysed. Indices of BLUP breeding values were calculated based on 7 traits with known genetic parameters (ranking in the championship, style rating on days 1, 2, and 3, and penalty points on days 1, 2, and 3). A low and irregular genetic trend, significant only in the case of penalties scored on days 1 and 2 of the championships, was shown. Compatibility of the evaluation of the breeding value estimated on the basis of scores achieved in the Polish Championships for Young Horses with the scores of the performance test carried out in Training Centres was shown. It was also demonstrated that the “sum penalty” and “sum style” measured during the three days of the Championships is sufficient for evaluation of the BLUP breeding value. It was suggested that the evaluation combined with the results achieved at the PCYH (in four age categories) would provide a more detailed picture of the genetic predispositions of jumping horses.

scholarly journals К проблеме использования инбридинга в мясном скотоводстве

2018 ◽  
Vol 8 (1) ◽  
pp. 596-600
Author(s):  
A.N. Ugnivenko
Keyword(s):  
Growth Rate ◽  
Reproductive Performance ◽  
Negative Impact ◽  
Breeding Value ◽  
Cattle Breeding ◽  
Maternal Line ◽  
Breeding Values ◽  
Reproductive Ability ◽  
Milk Performance ◽  
Males And Females

<p><span lang="EN-US">The influence of homogenous and heterogenous mating of parents on female productivity and breeding value of the sires of Ukrainian Beef has been studied. Inbred males and females have different breeding values in meet cattle breeding. Large number of improvers of growth rate were found among the sires, obtained from related mating. In females, inbred depression by growth rate, reproductive performance and milk performance has been observed. Cows, obtained from the linebreeding had the lowest milk performance and reproductive ability. It is not recommended to use related mating in meet cattle breeding</span><span lang="EN-US">for females obtaining, due to inbred depression. Mating of parents with inbreeding to the maternal line ancestor or “mediator” leads to heterosis by milk and reproductive ability. Heterogenity of parents by indexes of antigen similarity (r<sub>as</sub>) or body tallness index (IBT) reduces the negative impact of inbreeding. Inbreeding</span><span lang="EN-US">applied</span><span lang="EN-US">on</span><span lang="EN-US">parents</span><span lang="EN-US">that</span><span lang="EN-US">were</span><span lang="EN-US">different</span><span lang="EN-US">by</span><span lang="EN-US">conformation type and ancestry is less risky as compared to homogenous animals.</span></p>

scholarly journals Weaning results of beef Hungarian Fleckvieh calves 2. Genetic parameters, breeding values

2010 ◽  
Vol 53 (1) ◽  
pp. 26-36 ◽  
Author(s):  
S. Bene ◽  
I. Füller ◽  
A. Fördős ◽  
F. Szabó
Keyword(s):  
Genetic Parameters ◽  
Correlation Coefficients ◽  
Breeding Value ◽  
Phenotypic Variance ◽  
Weaning Weight ◽  
Breeding Values ◽  
Estimated Breeding Values ◽  
Genetic Value ◽  
Maternal Heritability ◽  
Daily Gain

Abstract. Weaning weight, preweaning daily gain and 205-day weight of Hungarian Fleckvieh calves (n=8 929, bulls =4 539, heifers =4 390) born from 232 sires between 1980 and 2003 were examined. Variance, covariance components and heritability values and correlation coefficients were estimated. The effect of the maternal permanent environment on genetic parameters and breeding values were examined. Two animal models were used for breeding value estimation. The direct heritability (hd2) of weaning weight, preweaning daily gain and 205-day weight was between 0.37 and 0.42. The maternal heritability (hm2) of these traits was 0.06 and 0.07. The direct-maternal correlations (rdm) were medium and negative −0.52 and −0.74. Contribution of the maternal heritability and maternal permanent environment to phenotype is smaller than that of direct heritabilities (hm2+c2< hd2). The ratio of the variance of maternal permanent environment in the phenotypic variance (c2) changed from 3 to 6 %. Estimated breeding values changed whether the permanent environmental effect of dam wasn’t taken into consideration but the rank of the animals was not modified. The genetic value for weaning results of Hungarian Fleckvieh population has increased since 1997.

Genetic analysis of feet and leg traits of Australian Angus cattle using linear and threshold models

2012 ◽  
Vol 52 (1) ◽  
pp. 1 ◽  
Author(s):  
Gilbert Jeyaruban ◽  
Bruce Tier ◽  
David Johnston ◽  
Hans Graser
Keyword(s):  
Animal Model ◽  
Genetic Correlation ◽  
Genetic Parameters ◽  
Genetic Evaluation ◽  
The Other ◽  
Breeding Value ◽  
Value Analysis ◽  
Breeding Values ◽  
Angus Cattle ◽  
Six Traits

The advantages of using a univariate threshold animal model (TAM) over the conventional linear animal model (AM) in the development of a genetic evaluation system for feet and leg traits of Angus cattle were explored. The traits were scored on a scale of 1–9 with scores 5 and 6 being the most desirable. The genetic parameters and estimated breeding values for front feet angle (FA), rear feet angle (RA), front feet claw set (FC), rear feet claw set (RC), rear leg hind view (RH) and rear leg side view (RS) were compared from AM and TAM. In order to predict breeding values to identify the animals with intermediate optimum, the scores were categorised to form three groups to differentiate the desirable group (5–6) from the other two groups with less desirable feet and leg appearances (1–4 and 7–9). The AM and TAM were used to estimate genetic parameters for the grouped data as well as the original score data. A TAM using the group data was used to predict the probability and breeding value for the desirable intermediate group. For the original score data, estimated heritabilities on the underlying scale, using TAM, were 0.50, 0.46, 0.35, 0.44, 0.32 and 0.22 for FA, FC, RA, RC, RH and RS, respectively, and were 0.01–0.18 higher than the heritabilities estimated using AM. Genetic correlation between the six traits using a bivariate TAM with all scores ranged from 0.02 to 0.50 with front and rear angles had the highest genetic correlation at 0.50. For all six traits, proportion in the intermediate desirable group was higher than the other two groups combined. The low annual genetic change observed for all six traits over the 10 years of data recording reflected the lack of directional selection to improve the traits in Angus cattle. For genetic evaluation of feet and leg traits with an intermediate optimum, TAM is a preferred method for estimating genetic parameters and predicting breeding values for the desirable category. The TAM has now been implemented for regular estimated breeding value analysis of feet and leg traits of Angus cattle.

scholarly journals Genetic Parameters For Milk Traits In Egyptian Native Cows

2021 ◽  
Author(s):  
Safaa Salah Sanad ◽  
Mahmod Ghreeb Gharib
Keyword(s):  
Genetic Parameters ◽  
Economic Value ◽  
Breeding Value ◽  
Lactation Period ◽  
Production Traits ◽  
Dry Period ◽  
Milk Traits ◽  
Local Breed ◽  
Breeding Values ◽  
National Wealth

Abstract The aim of this study is to estimate the genetic parameters and the effect of non-genetic factors for some milk traits including total milk yield (TMY/kg), Lactation period (LP/day), number of services per conception (NSC), days open (DO), calving interval (CI) and dry period (DP). Data were collected from two farms. Experimental Farm belonging to (APRI) data included 1829 records. The statistical analysis has been adopted using animal models. Actual means of TMY/kg, LP/day, NSC/services, DO/day, CI/day and DP/day were 791.3, 171.1, 1.8, 109, 402.7 and 79.3 respectively. Estimated heritability (h2) of TMY, LP, NSC, DO, CI, and DP were 0.18± 0.01, 0.18± 0.001, 0.07± 0.016, 0.09± 0.041 and 0.09±0.001 respectively. The ranges of breeding values BV of cows for TMY/kg, LP/day, NSC, /services, DO/day, CI/day and DP/day were 776.5, 26.7, 6.7, 13.4, 77.1 and 11.5 respectively. The estimated Predicted Breeding Value PBV for all traits varied widely. The genetic trends of cow breeding values were significant for all studied traits. This confirms that the genetic improvement of these traits leads to increased milk production traits. The study recommends preserving the Native Egyptian dairy cattle because they represent a national wealth that must be preserved from extinction through inventorying the genetic resources, characterization and evaluation of this local breed to benefit from it in improving animal breeds of high economic value. Due to the distinction of Egyptian domestic cows for their resistance to various environmental conditions.

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