Joint estimation of (co) variance components and breeding values for mean and dispersion of days from calving to first service in Holstein cow

2017 ◽  
Vol 57 (4) ◽  
pp. 760 ◽  
Author(s):  
Heydar Ghiasi ◽  
Majbritt Felleki
Keyword(s):  
Standard Deviation ◽  
Genetic Correlation ◽  
Additive Genetic Variance ◽  
Joint Estimation ◽  
Breeding Value ◽  
Genetic Trend ◽  
Breeding Values ◽  
The Mean ◽  
Estimated Breeding Values ◽  
Genetic Standard Deviation

The present study explored the possibility of selection for uniformity of days from calving to first service (DFS) in dairy cattle. A double hierarchical generalised linear model with an iterative reweighted least-squares algorithm was used to estimate covariance components for the mean and dispersion of DFS. Data included the records of 27 113 Iranian Holstein cows (parity, 1–6) in 15 herds from 1981 to 2007. The estimated additive genetic variance for the mean and dispersion were 32.25 and 0.0139; both of these values had low standard errors. The genetic standard deviation for dispersion of DFS was 0.117, indicating that decreasing the estimated breeding value of dispersion by one genetic standard deviation can increase the uniformity by 12%. A strong positive genetic correlation (0.689) was obtained between the mean and dispersion of DFS. This genetic correlation is favourable since one of the aims of breeding is to simultaneously decrease the mean and increase the uniformity of DFS. The Spearman rank correlations between estimated breeding values in the mean and dispersion for sires with a different number of daughter observations were 0.907. In the studied population, the genetic trend in the mean of DFS was significant and favourable (–0.063 days/year), but the genetic trend in the dispersion of DFS was not significantly different from zero. The results obtained in the present study indicated that the mean and uniformity of DFS can simultaneously be improved in dairy cows.

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.

Repeatability and bias of estimated breeding values for dairy bulls and bull dams calculated from animal model evaluations

1993 ◽  
Vol 57 (2) ◽  
pp. 175-182 ◽  
Author(s):  
P. Uimari ◽  
E. A. Mäntysaari
Keyword(s):  
Animal Model ◽  
Dairy Cow ◽  
Relative Weight ◽  
Breeding Value ◽  
Potential Bias ◽  
Data Set ◽  
Breeding Values ◽  
Dairy Bulls ◽  
Estimated Breeding Values ◽  
Genetic Standard Deviation

AbstractAn animal model and an approximative method for calculating repeatabilities of estimated breeding values are used in Finnish dairy cow evaluation. Changes in estimated breeding values over time as daughters accumulate were studied. Special emphasis was given to the accuracy and potential bias in the pedigree indices of young sires. The data set used was the same as in the national evaluation and the traits investigated were protein yield and somatic cell count. The average repeatability in evaluation of bulls without daughters was 0·37. The empirical repeatability defined as a squared correlation between the pedigree index and the final sire proof was only 0·15. The reduction in the repeatability was attributed to the selection on pedigree index. The upward bias observed in pedigree indices was 5 kg (approx. 0·3 of genetic standard deviation). The bias was caused by the overestimation of bull dams' breeding value. Also the proofs of bull sires increased after the second crop of daughters. The correlation between the evaluations of the same sire calculated from two separate equal size daughter groups was 0·91 when the bull had 10 to 50 daughters and 0·87 with over 100 daughters. This illustrates how the relative weight of the pedigree decreases while more progeny information is accumulated in the evaluation.

scholarly journals Analysis of non-genetic and genetic influences underlying the growth of Kajli lambs

2020 ◽  
Vol 50 (4) ◽  
pp. 613-625
Author(s):  
A. Ali ◽  
K. Javed ◽  
I. Zahoor ◽  
K.M. Anjum
Keyword(s):  
Birth Weight ◽  
Genetic Correlation ◽  
Fixed Effects ◽  
Genetic Correlations ◽  
Breeding Value ◽  
Season Of Birth ◽  
Genetic Trend ◽  
Breeding Values ◽  
Heritability Estimates ◽  
Birth Type

Data on 2931 Kajli lambs, born from 2007 to 2018, were used to quantify environmental and genetic effects on growth performance of Kajli sheep. Traits considered for evaluation were birth weight (BWT), 120-day adjusted weight (120DWT), 180-day adjusted weight (180DWT), 270-day adjusted weight (270DWT), and 365-day adjusted weight (365DWT). Fixed effects of year of birth, season of birth, sex, birth type, and dam age on these traits were evaluated using linear procedures of SAS, 9.1. Similarly, BWT, 120DWT, 180DWT, and 270DWT were used as fixed effects mixed model analyses. Variance components, heritability and breeding values were estimated by restricted maximum likelihood. The genetic trend for each trait was obtained by regression of the estimated breeding values (EBV) on year of birth. Analyses revealed substantial influence of birth year on all traits. Sex and birth type were the significant sources of variation for BWT and 120DWT. Season of birth did not influence birth weight meaningfully, but had a significant role in the expression of 120DWT, 180DWT, and 270DWT. Heritability estimates were generally low (0.003 ± 0.018 to 0.099 ± 0.067) for all traits. With the exception of the genetic correlation of 180DWT and 365DWT, the genetic correlations between trait were strong and positive. Only 365DWT had a positive genetic trend. Although the heritability estimates for almost all weight traits were low, high and positive genetic correlations between BWT and other weight traits suggest that selection based on BWT would result in the improvement of other weight traits as a correlated response.Keywords: bodyweight, breeding value, genetic correlation, sheep

scholarly journals Genetic trend for jumping performance in Czech warm-blooded horses

2004 ◽  
Vol 52 (1) ◽  
pp. 97-102
Author(s):  
Iva Jiskrová
Keyword(s):  
Animal Model ◽  
Regression Analysis ◽  
Regression Coefficient ◽  
Breeding Value ◽  
Positive Trend ◽  
Genetic Trend ◽  
Breeding Values ◽  
Jumping Performance ◽  
The Mean ◽  
Estimated Breeding Value

Data on the jumping performance of horses in the period of 1991 - 2002 were analysed. The data included 252781 starts of 10671 horses in 10911 jumping competitions. The performance was characterised on the basis of the obtained bad points (penalties) of the competing horses. The BLUP Animal model was used to estimate the breeding value of the sport horses; the genetic trend in the jumping performance of the Czech warm-blooded horse was assessed on the basis of these results. Regression analysis and calculations of the mean breeding values based on the year of birth were used to determine the dependence of the estimated breeding value on the year of birth. The jumping performance of the population of the Czech warm-blooded horse shows a positive trend. The regression coefficient of –0.1337 shows the genetic trend in the population, which means an increasing jumping performance of the horses expressed in reduced earnings of bad points by 0.1337 in dependence on the year of birth.

Selection on purebred and crossbred Performance for litter size in pigs*

2000 ◽  
Vol 43 (3) ◽  
pp. 249-262 ◽  
Author(s):  
M. Bösch ◽  
R. Röhe ◽  
H. Looft ◽  
E. Kalm
Keyword(s):  
Genetic Correlation ◽  
Litter Size ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Genetic Parameter ◽  
Selection Method ◽  
Data Sets ◽  
Phenotypic Variance ◽  
Breeding Values ◽  
Estimated Breeding Values

Abstract. The present study deals with estimation of genetic parameter for purebred and crossbred Performance of live born piglets, in order to choose the optimal selection method. Data sets of two pure breeds, line L03 and L04, with 5,422 sows, a two line crossbred, L303, with 3,553 sows and a three line crossbred, L350, with 3,609 sows of a North-German breeding Company were recorded. Estimated genetic correlation between purebred and crossbred Performance were rg = 0.59 and 0.40 for reciprocal crosses L03xL04 and L04xL03, respectively. Further investigations showed that the genetic correlation is influenced by genotype-environment interactions between a nucleus farm and a farm on production level. Full-sib effects showed a proportion of FS = 0.06 on the phenotypic variance of litter size. They were confounded with additive genetic variance and permanent environment variance, when full-sib effects were neglected. The percentage of equal selected purebred sires of line L03 were 80% when 30% of the sires selected on purebred or crossbred breeding values. Accuracy of estimated breeding values of purebred sires increased when crossbred Information were considered additionally from 0.32 to 0.38 for line L03 and 0.46 to 0.47 for line L04. Genetic correlation between purebred and crossbred Performance, the genetic connectedness between nucleus and production and the presence of genotype-environment interactions were analysed to have high influence on the value of additionally considered crossbred Performance.

scholarly journals Implementation of an Economic Lifetime Net Merit for the Dual-Purpose German Black Pied Cattle Breed

Agriculture ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 41
Author(s):  
Saskia Meier ◽  
Danny Arends ◽  
Paula Korkuć ◽  
Sandra Kipp ◽  
Dierck Segelke ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Dairy Cattle ◽  
Milk Yield ◽  
Cattle Breed ◽  
Breeding Value ◽  
Dual Purpose ◽  
Breeding Values ◽  
Fitness Traits ◽  
Milk Performance ◽  
Estimated Breeding Values

Recently, a Total Merit Index (RZ€) has been developed for German Holstein dairy cattle on the basis of margin in Euro. Our aim was to adjust this lifetime net merit for the dual-purpose German Black Pied cattle breed (DSN) accounting for beef production in addition to milk performance and fitness traits. We used the estimated breeding values of DSN sires and developed a breeding value for carcass weight and quality. Furthermore, we adjusted the German Holstein marginal profits per standard deviation, which are used to calculate the estimated breeding values, to DSN-specific values. The DSN Net Merit is the sum of the three sub-indices DSN Net Milk, DSN Net Fitness, and DSN Net Beef, which contribute to the DSN Net Merit with 52.84%, 43.43%, and 3.73%, respectively. The DSN Net Merit that was calculated for 33 DSN sires ranged between EUR −1114 and +709. The DSN Net Merit strongly correlates with the Total Merit Index. The implementation of the DSN Net Merit is useful for selection and mating decisions. Especially, the sub-index DSN Net Beef, which does not correlate with existing breeding values, can be used to maintain the dual-purpose character of DSN while modestly improving milk yield. The approach can be easily adapted to other dual-purpose breeds.

scholarly journals Genetic trend of functional productive life in the population of black and white cattle in Serbia

Genetika ◽  
2018 ◽  
Vol 50 (3) ◽  
pp. 855-862 ◽  
Author(s):  
Dragan Stanojevic ◽  
Radica Djedovic ◽  
Vladan Bogdanovic ◽  
Nikola Raguz ◽  
Denis Kucevic ◽  
...  
Keyword(s):  
Average Length ◽  
Breeding Value ◽  
Genetic Trend ◽  
Breeding Values ◽  
Productive Life ◽  
Black And White ◽  
Time Period ◽  
Average Share ◽  
White Cattle ◽  
Estimated Breeding Values

This research was conducted with the aim ?f estimating genetic trend for a functional length of productive life (FLPL) in the population of Black and White cattle in Serbia. Research and bulls genetic evaluation for functional longevity were performed on a set of data provided by Agricultural Corporation Belgrade AD (PKB) which contained data on longevity and origin of 22109 cows out of which 26% records were right-censored. Functional length of productive life (FPLP) represents a time period from the first calving to culling or censoring corrected for milk production. Breeding values were estimated using Weibull method of proportional risks within survival analysis a genetic trend for FLPL was calculated using of a regression analysis. The cows included in the analysis were on average first calved in the age of 809 days and had an average share of 81.9% genes of Holstein Friesian breed. An average length of productive life was 1267 days (41.6 months). Distribution of bull standardised breeding values did not statistically significantly differ from normal distribution. An average standardised breeding value was 99. A slightly positive genetic trend was determined, that is, the length of functional productive life was by selection increased by 0.021 day at an annual level while a reliability of estimated breeding values showed a negative trend.

Practical aspects of a genetic evaluation system using parentage assigned from genetic markers

2005 ◽  
Vol 45 (8) ◽  
pp. 935 ◽  
Author(s):  
K. G. Dodds ◽  
J. A. Sise ◽  
M. L. Tate
Keyword(s):  
Genetic Markers ◽  
Evaluation System ◽  
Fixed Effects ◽  
Genetic Evaluation ◽  
Diagnostic Systems ◽  
Breeding Values ◽  
Mating Group ◽  
Animal Management ◽  
The Mean ◽  
Estimated Breeding Values

Animal breeding values can be calculated when genetic markers have been used to help determine the parentage of some of the animals, but their parentage has been incompletely determined. The pedigree sampling method is 1 computing strategy for calculating these breeding values. This paper describes and discusses methods for dealing with a number of practical issues that arise when implementing such a system for industry use. In particular, diagnostic systems for detecting inadequacies or possible errors in the genotyping systems and the recording of animal management are developed. Also, characteristics of the best assigned pedigrees are calculated according to mating group and used to check for sires missing from these groups. The correlation between breeding values estimated from a single sampled pedigree (using parentage probabilities) and those estimated as the mean from many sampled pedigrees gives a diagnostic to indicate which estimated breeding values are more influenced by uncertainties in relationships. For the analysis of survival traits, a method to enumerate and assign likely parentage to dead offspring which have not been DNA sampled and genotyped is described. When embryo transfer technology is used, the genetic dam needs to be included as a possible dam when considering parentage. If some fixed effects which depend on the parent are missing, these can be sampled similarly to parentage, and this may improve the evaluation if certain assumptions are met. A method to provide a likely list of parents, the ‘fitted pedigree’, which is based on the most likely parents, but modified to reduce the occurrence of unlikely family sets (e.g. very large litters) is also presented. The use of these methods will enhance the practical application of DNA parenting when used in conjunction with genetic evaluation.

scholarly journals Prevalence and breeding values of elbow dysplasia in the Estrela mountain dog

2013 ◽  
Vol 58 (No. 9) ◽  
pp. 484-490 ◽  
Author(s):  
S. Alves-Pimenta ◽  
B. Colaco ◽  
AM Silvestre ◽  
MM Ginja
Keyword(s):  
Hip Dysplasia ◽  
Mass Selection ◽  
Genetic Trend ◽  
Genetic Progress ◽  
Breeding Values ◽  
Elbow Dysplasia ◽  
Low Mass ◽  
The Mean ◽  
Dog Breed ◽  
Genetic Trends

The aims of this study were to determine the prevalence and heritability of elbow dysplasia in the Estrela mountain dog breed, to investigate genetic trends over the last 20 years (1990–2009) and to evaluate the association of individual records with breeding values. The elbows of 351 Estrela mountain dogs were examined using the flexed mediolateral radiographic view and evaluated using the International Elbow Working Group scoring system. Heritability and breeding values were estimated using a linear model. Elbow Dysplasia was found in 16.5% (59/351) of the dogs; males (27%, 34/127) were more affected than females (11%, 24/224) (P < 0.05). The heritability was very low (0.065) and the genetic trend showed a slight positive slope with an improvement in 2004 and 2005. The mean breeding values in elbow dysplasia grades were different but the overlap among grades was very pronounced. The prevalence and heritability of elbow dysplasia in the breed are thus low. Mass selection using individual phenotypes may not be effective. Elbow dysplasia genetic trends are similar to trends for hip dysplasia and passive hip laxity, so the use of selection against hip dysplasia may also result in genetic progress for elbow dysplasia.  

scholarly journals Genetic parameters and genomic breeding values for digital dermatitis in Holstein Friesian dairy cattle: host susceptibility, infectivity and the basic reproduction ratio

2019 ◽  
Vol 51 (1) ◽  
Author(s):  
Floor Biemans ◽  
Mart C. M. de Jong ◽  
Piter Bijma
Keyword(s):  
Standard Deviation ◽  
Dairy Cattle ◽  
Genetic Effect ◽  
Host Susceptibility ◽  
Basic Reproduction Ratio ◽  
Reproduction Ratio ◽  
Genomic Breeding ◽  
Holstein Friesian ◽  
The Mean ◽  
Genetic Standard Deviation

Abstract Background For infectious diseases, the probability that an animal gets infected depends on its own susceptibility, and on the number of infectious herd mates and their infectivity. Together with the duration of the infectious period, susceptibility and infectivity determine the basic reproduction ratio of the disease ($$ R_{0} $$R0). $$ R_{0} $$R0 is the average number of secondary cases caused by a typical infectious individual in an otherwise uninfected population. An infectious disease dies out when $$ R_{0} $$R0 is lower than 1. Thus, breeding strategies that aim at reducing disease prevalence should focus on reducing $$ R_{0} $$R0, preferably to a value lower than 1. In animal breeding, however, $$ R_{0} $$R0 has received little attention. Here, we estimate the additive genetic variance in host susceptibility, host infectivity, and $$ R_{0} $$R0 for the endemic claw disease digital dermatitis (DD) in Holstein Friesian dairy cattle, and estimate genomic breeding values (GEBV) for these traits. We recorded DD disease status of both hind claws of 1513 cows from 12 Dutch dairy farms, every 2 weeks, 11 times. The genotype data consisted of 75,904 single nucleotide polymorphisms (SNPs) for 1401 of the cows. We modelled the probability that a cow got infected between recordings, and compared four generalized linear mixed models. All models included a genetic effect for susceptibility; Models 2 and 4 also included a genetic effect for infectivity, while Models 1 and 2 included a farm*period interaction. We corrected for variation in exposure to infectious herd mates via an offset. Results GEBV for $$ R_{0} $$R0 from the model that included genetic effects for susceptibility only had an accuracy of ~ 0.39 based on cross-validation between farms, which is very high given the limited amount of data and the complexity of the trait. Models with a genetic effect for infectivity showed a larger bias, but also a slightly higher accuracy of GEBV. Additive genetic standard deviation for $$ R_{0} $$R0 was large, i.e. ~ 1.17, while the mean $$ R_{0} $$R0 was 2.36. Conclusions GEBV for $$ R_{0} $$R0 showed substantial variation. The mean $$ R_{0} $$R0 was only about one genetic standard deviation greater than 1. These results suggest that lowering DD prevalence by selective breeding is promising.

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