Comparison of different traits to evaluate the growth of bulls

The live weights of 8 243 performance-tested bulls from 100 to 400 days of age were analysed using random regression (RR) and single-trait animal models. Evaluations were done for live weight at 400 days of age and gains from 100 to 400 days of age at various monthly intervals. Estimates of variance components differed depending on the trait definition and model of analysis. Systematic environmental effects explained a higher proportion of variability in the RR for gains than for other definitions of growth. The expected average reliability of estimated breeding values was similar for all methods from 0.42 to 46, but the rankings of animals differed. Determinations (r2) of breeding values between methods ranged from 0.64 to 0.94. Correlations of the breeding values of progeny at performance-test stations with parents were highest for the evaluation of gains in consecutive intervals evaluated by RR. Correlations of the breeding values of sires from their growth at performance-test stations with the breeding values of groups of progeny at progeny-test stations were from 0.26 to 0.38. Correlations were the highest for RR evaluations of gain using consecutive short intervals. Evaluation of the growth of animals according to daily gains in short consecutive intervals was preferred because more animals and more observations per animal were included in the evaluations, and the growth curve was separated into genetic and non-genetic parts. Simple evaluation of growth according to the final weight or daily gain in a long interval is not entirely correct, since environmental compensatory growth can occur.

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Models for evaluation of growth of performance tested bulls

Czech Journal of Animal Science ◽

10.17221/331-cjas ◽

2008 ◽

Vol 53 (No. 2) ◽

pp. 45-54 ◽

Cited By ~ 4

Author(s):

J. Přibyl ◽

H. Krejčová ◽

J. Přibylova ◽

I. Misztal ◽

S. Tsuruta ◽

...

Keyword(s):

Growth Curve ◽

Variance Components ◽

Legendre Polynomials ◽

Performance Test ◽

Live Weight ◽

Random Regression ◽

Mild Depression ◽

Average Growth ◽

Linear Spline

Before being used for insemination, young bulls of Czech Fleckvieh (CF) are tested for growth at performance-test stations. While at stations, the bulls are weighed monthly. Evaluation included 7 448 bulls with 82 676 records of weight measured from 6 to 520 days of life. In the station-year-period (HYS), which can be prolonged up to 3 months, different groups were tested according to the beginning of growth curve and according to test-days of weighing. Weight analyses were used to handle heterogeneous variability based on age. Legendre Polynomials (LP) with 5 parameters described the average growth curve for HYS classes. Deviations from average curves were decomposed into genetic (G), animal’s permanent environment (PE) and residual (RES) components. Functions of (G) and (PE) were tested using LP random regression (RR) methodology with 5 or 3 parameters and Linear Spline (SP) function with 5 knots. Variance increases with the age of the animals. From 100 to 400 days, heritability was nearly the same with a mild depression in the middle of the period. The average was h2 = 0.31 and ended with h2 = 0.36. Results were similar for variance components, heritability, genetic, environmental and phenotype correlations from different models with different LP and SP functions. Higher RES variability occurred only for LP with 3 parameters. For traits like live weight, the RR should have at least 3 parameters and SP function should be used.

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Comparison of Breeding Values for Daily Gains of Bulls Estimated with Multi-Trait and Random Regression Models

Archives Animal Breeding ◽

10.5194/aab-50-147-2007 ◽

2007 ◽

Vol 50 (2) ◽

pp. 147-154

Author(s):

H. Krejčová ◽

N. Mielenz ◽

J. Přibyl ◽

L. Schüler

Keyword(s):

Legendre Polynomials ◽

Regression Models ◽

Reference Model ◽

Average Daily Gain ◽

Regression Coefficients ◽

Random Regression ◽

Breeding Values ◽

Higher Rank ◽

Estimated Breeding Values ◽

Daily Gain

Abstract. In this study, random regression models with Legendre polynomials of the 2nd, 3rd and 4th degree (RR2, RR3 and RR4) are compared with regard to the estimation of breeding values for the average daily gain of Czech Pied bulls (Simmental type). The data were prepared such that a multi-trait model (MTM) could be used as reference model. For each bull, 8 repeated records or fewer were available for the testing period from the 12th to the 420th day of life. For the modeling of the expected value structure, the fixed regression coefficients of the Legendre polynomials were subordinated hierarchically to the herd-year-season effects (HYS). For the comparison of the random regression models with the reference model, rank correlations between the estimated breeding values of various animal groups were calculated and a variety of top-lists were analyzed. In general, models RR3 and RR4 returned higher rank correlations with MTM in comparison to model RR2. Additionally, the number of common animals in the 1% and 10% top-lists showed that models RR3 and RR4 are to be preferred over RR2 when it comes to the estimation of breeding values.

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Trajectory of body weight of performance tested dual-purpose bulls

Czech Journal of Animal Science ◽

10.17221/2340-cjas ◽

2008 ◽

Vol 52 (No. 10) ◽

pp. 315-324 ◽

Cited By ~ 4

Author(s):

J. Přibyl ◽

H. Krejčová ◽

J. Přibylová ◽

I. Misztal ◽

J. Bohmanová ◽

...

Keyword(s):

Variance Components ◽

Fixed Effects ◽

Spline Function ◽

Performance Test ◽

Live Weight ◽

Random Regression ◽

Dual Purpose ◽

Basic Model ◽

Body Weights ◽

Dual Purpose Cattle

6 508 bulls of dual-purpose cattle at performance-test stations were weighed at intervals of 30 days from birth to 420 days. After all editing a total of 74 558 weight records were available. Live weight was evaluated by orthogonal Legendre Polynomial (LP) of degree 4 and by Linear Spline function (SP) with 5 knots. The fixed effects of test-day-year-station of weighing (TDS) and LP within station-year explain together 97% of variability. Variance components were estimated by REML (REMLF90 programme) taking into account heterogeneous variance during growth. The basic model included fixed effects: TDS, and fixed regression on age (LPF), and random regression for additive genetic (SPG) and permanent environmental of the animal (SPPE) effects. Variability of all components increases with age. During the 50–400 day period the heritability is 0.28 on average. Heritability increases with the age of the animal; it is the highest at the end of the period. Correlations for body weights between different ages of the animal are high.

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

Genetics Selection Evolution ◽

10.1186/s12711-019-0510-6 ◽

2019 ◽

Vol 51 (1) ◽

Cited By ~ 6

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.

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Estimated variance components and breeding values for pre-weaning growth criteria in Romney sheep

Jurnal Ilmu Ternak dan Veteriner ◽

10.14334/jitv.v21i2.1353 ◽

2017 ◽

Vol 21 (2) ◽

pp. 73

Author(s):

Eslam Faid-Allah ◽

E. Ghoneim ◽

A.H.M. Ibrahim

Keyword(s):

New Zealand ◽

Variance Components ◽

Genetic Factors ◽

Gene Marker ◽

Breeding Values ◽

Factors Affecting ◽

Kleiber Ratio ◽

Body Weights ◽

Estimated Breeding Values ◽

Positive Coefficients

This study was carried out to investigate variance components, direct heritability, maternal genetic parameters, estimated breeding values and factors affecting pre-weaning growth criteria of Romney sheep. Data were collected over the period from 2006 to 2012 with records of 4989 lambs descended from 76 rams and 2190 ewes of Romney sheep maintained at S. Island of New Zealand via Gene Marker Lab., Faculty of Agric. and Life Sci., Lincoln Univ., New Zealand. Results proved that genetic and non-genetic factors affecting studied criteria had significant effects (P<0.05). Genetic and environmental estimates of live body weights at birth (LBW), weaning (LWW) and Kleiber ratio (KR) were 0.20±0.074, 0.15±0.042 and 0.14±0.052 for direct heritability (h2a±SE); 0.59±0.219, 0.41±0.023 and 0.08±0.002 for maternal heritability (h2m±SE); 0.11684, 2.6378 and 0.27565 for additive variances (σ2a), 0.34596, 7.1179 and 0.14532 for maternal variances (σ2m); and 0.002395, 10.1262 and 0.509339 for permanent environmental variances (σ2e), respectively. EBV’s of LBW, LWW and KR ranged from -0.555: 0.502, -1.554: 3.006 and -0.633: 0.242 direct, -0.863: 0.954, -4.942: 2.554 and -0.469: 0.179 maternal for rams, respectively; and -0.664: 0.830, -2.996: 4.586 and -1.651: 0.677 direct, 1.429: 1.142, -7.541: 4.920 and -1.223: 0.492 maternal for ewes, respectively. Results suggest the importance of considering the non-genetic factors in pre-weaning growth performance of lambs. Moderate heritability and positive coefficients of phenotypic and genetic correlation for studied criteria indicate to the possibility of improving them using traditional selection.

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Reliability of breeding values between random regression and 305-day lactation models

Pesquisa Agropecuária Brasileira ◽

10.1590/s0100-204x2016001100007 ◽

2016 ◽

Vol 51 (11) ◽

pp. 1848-1856

Author(s):

Alessandro Haiduck Padilha ◽

◽

Jaime Araujo Cobuci ◽

Darlene dos Santos Daltro ◽

José Braccini Neto

Keyword(s):

Legendre Polynomials ◽

Regression Models ◽

Protein Yield ◽

Random Regression ◽

Holstein Cattle ◽

Average Increase ◽

Data Set ◽

Breeding Values ◽

Estimated Breeding Values ◽

Genetic Evaluations

Abstract The objective of this work was to verify the gain in reliability of estimated breeding values (EBVs), when random regression models are applied instead of conventional 305-day lactation models, using fat and protein yield records of Brazilian Holstein cattle for future genetic evaluations. Data set contained 262,426 test-day fat and protein yield records, and 30,228 fat and protein lactation records at 305 days from first lactation. Single trait random regression models using Legendre polynomials and single trait lactation models were applied. Heritability for 305-day yield from lactation models was 0.24 (fat) and 0.17 (protein), and from random regression models was 0.20 (fat) and 0.21 (protein). Spearman correlations of EBVs, between lactation models and random regression models, for 305-day yield, ranged from 0.86 to 0.97 and 0.86 to 0.98 (bulls), and from 0.80 to 0.89 and 0.81 to 0.86 (cows), for fat and protein, respectively. Average increase in reliability of EBVs for 305-day yield of bulls ranged from 2 to 16% (fat) and from 4 to 26% (protein), and average reliability of cows ranged from 24 to 38% (fat and protein), which is higher than in the lactation models. Random regression models using Legendre polynomials will improve genetic evaluations of Brazilian Holstein cattle due to the reliability increase of EBVs, in comparison with 305-day lactation models.

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

Archives Animal Breeding ◽

10.5194/aab-53-26-2010 ◽

2010 ◽

Vol 53 (1) ◽

pp. 26-36 ◽

Cited By ~ 1

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.

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Bias in genetic evaluation using random regression test-day model

Agricultural and Food Science ◽

10.2137/145960607782219300 ◽

2008 ◽

Vol 16 (2) ◽

pp. 103 ◽

Cited By ~ 1

Author(s):

M. LIDAUER ◽

E.A. MÄNTYSAARI

Keyword(s):

Animal Model ◽

Evaluation Model ◽

Protein Yield ◽

Random Regression ◽

Data Sets ◽

Heterogeneous Variance ◽

Breeding Values ◽

Regression Test ◽

Estimated Breeding Values ◽

Reduced Data

The effect of an upgraded Finnish evaluation model on bias in estimated breeding values for protein yield was investigated. Evaluations based on repeatability animal model and on random regression test-day model without and with heterogeneous variance adjustment were compared. Comparisons were based on the average difference between pedigree indices and the future estimated breeding values, based on own or on daughter performance records. This was defined as empirical bias. The pedigree indices were computed from reduced data sets where four years of the most recent data were excluded. Results showed an upward bias in the protein yield pedigree indices for Ayrshire young sires of 2.2 kg, 2.5 kg and 1.8 kg from the repeatability animal model, random regression test-day model and random regression test-day model with heterogeneous variance adjustment, respectively. Pedigree indices for daughters of young sires were upward biased, whereas pedigree indices for daughters of proven sires were slightly underestimated when heterogeneous variance was not accounted. Inclusion of test-day yields from the fourth lactation onwards increased the bias. Moving from repeatability animal model to random regression test-day model did not reduce the bias, whereas adjustment of heterogeneous variance reduced bias.;

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Analysis of censored survival data using random regression models

Animal Science ◽

10.1017/s1357729800055491 ◽

2001 ◽

Vol 72 (1) ◽

pp. 1-10 ◽

Cited By ~ 40

Author(s):

R. F. Veerkamp ◽

S. Brotherstone ◽

B. Engel ◽

T. H. E. Meuwissen

Keyword(s):

Milk Yield ◽

Survival Data ◽

Variance Components ◽

Regression Models ◽

Proportional Hazards ◽

Random Regression ◽

Breeding Values ◽

Censored Survival Data ◽

Proportional Hazards Models ◽

Randomly Censored Data

AbstractCensoring of records is a problem in the prediction of breeding values for longevity, because breeding values are required before actual lifespan is known. In this study we investigated the use of random regression models to analyse survival data, because this method combines some of the advantages of a multitrait approach and the more sophisticated proportional hazards models. A model was derived for the binary representation of survival data and links with proportional hazards models and generalized linear models are shown. Variance components and breeding values were predicted using a linear approximation, including time-dependent fixed effects and random regression coefficients. Production records in lactations 1 to 5 were available on 24741 cows in the UK, all having had the opportunity to survive five lactations. The random regression model contained a linear regression on milk yield within herd (no. = 1417) by lactation number (no. = 4), Holstein percentage and year-month of calving effect (no. = 72). The additive animal genetic effects were modelled using orthogonal polynomials of order 1 to 4 with random coefficients and the error terms were fitted for each lactation separately, either correlated or not. Variance components from the full (i.e. uncensored) data set, were used to predict breeding values for survival in each lactation from both uncensored and randomly censored data. In the uncensored data, estimates of heritabilities for culling probability in each lactation ranged from 0·02 to 0·04. Breeding values for lifespan (calculated from the survival breeding values) had a range of 2·4 to 3·6 lactations and a standard deviation of 0·25. Correlations between predicted breeding values for 129 bulls, each with more than 30 daughters, from the various data sets ranged from 0·81 to 0·99 and were insensitive to the model used. It is concluded that random regression analysis models used for test-day records analysis of milk yield, might also be of use in the analysis of censored survival data.

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Short-term selection for yearling weight in a small-experimental Iranian Afshari sheep flock

Canadian Journal of Animal Science ◽

10.4141/cjas08059 ◽

2009 ◽

Vol 89 (3) ◽

pp. 301-307 ◽

Cited By ~ 8

Author(s):

Farhad Ghafouri-Kesbi ◽

Moradpasha Eskandarinasab ◽

Ahmad Hassanabadi

Keyword(s):

Animal Model ◽

Average Daily Gain ◽

Genetic Correlations ◽

Live Weight ◽

Breeding Program ◽

Sheep Flock ◽

Breeding Values ◽

Generation Interval ◽

Selection For ◽

Daily Gain

A selection experiment was initiated in 2000 in an Afshari sheep flock at the department of animal breeding and genetics of the University of Zanjan, Iran. The aim was to evaluate the response of Afshari sheep to selection for yearling live weight. Here, we evaluate the results of this breeding program obtained between 2000 and 2005. Traits studied were birth weight (BW), weaning weight (WW), yearling weight (YW), average daily gain from birth to weaning (WWDG) and average daily gain from weaning to yearling age (YWDG). Mixed model methodology based on a multi-trait animal model was employed to estimate (co)variance components and corresponding genetic parameters. Estimates of breeding values were obtained by the best linear unbiased prediction (BLUP) method. Generation intervals on the four genetic pathways were estimated as the average age of parents at the birth of their progeny kept for reproduction. The heritability estimates were 0.34, 0.27, 0.14, 0.20 and 0.01 for BW, WW, YW, WWDG and YWDG, respectively. Estimates of genetic correlations among traits studied were positive, and ranged from low (0.07, YW/WWDG) to high (0.76, YW/YWDG). Genetic improvements over the experiment based on estimated breeding values were 0.104, 0.824, 1.247, 0.005 and ≈0.00 kg for BW, WW, YW, WWDG and YWDG, respectively. Annual genetic gain for YW was relatively high, 0.311 kg yr-1, which demonstrated the effectiveness of the implemented breeding program. Correlated responses in BW, WW, WWDG and YWDG were 0.021, 0.167, 0.001 and ≈0.00 kg yr-1, respectively. Estimates of heritabilities and observed genetic trends indicated that selective breeding can lead to significant genetic improvement in Afshari sheep. The average generation interval was estimated to be 3.35 yr. The shorter generation interval was observed on the sire side compared with the dam side (3.30 yr vs. 3.78 yr), indicating faster generation turnover for sires than for dams. Key words: Sheep, animal model, genetic trend, generation interval, heritability

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