Comparison of rolling front and discrete generation breeding strategies for trees

1998 ◽  
Vol 28 (7) ◽  
pp. 987-993 ◽  
Author(s):  
Nuno MG Borralho ◽  
Gregory W Dutkowski
Keyword(s):  
Stochastic Simulation ◽  
Mixed Model ◽  
Accurate Prediction ◽  
Breeding Value ◽  
Breeding Strategies ◽  
Breeding Values ◽  
Generation Interval ◽  
Value Estimation ◽  
Discrete Generation

Discrete generation and rolling front breeding strategies are compared in terms of gain and inbreeding over a period of 40 years using stochastic simulation. In the rolling front strategy, crosses are made between the best available trees in each year, and new progeny trials are established using the crosses done in the previous year, rather than waiting for all crosses in that generation to be completed. For a given amount of resources, the rolling front strategy resulted in 25-35% greater gains per year, mainly due to a shorter generation interval. Inbreeding was also higher in the rolling front, although gains per unit of inbreeding were consistently greater than with the discrete generation strategy. Despite the smaller size of trials and greater imbalance between trials in rolling front, the results suggest that breeding value estimation using mixed-model BLUP is robust enough to ensure accurate prediction of breeding values and maintain the advantage of the rolling front strategy.

Breeding Value Estimation for Pigs in Closed Nucleus Herds

1988 ◽  
Vol 1988 ◽  
pp. 12-12 ◽  
Author(s):  
Naomi R. Wray
Keyword(s):  
Fixed Effects ◽  
Mixed Model ◽  
Phenotypic Selection ◽  
Breeding Value ◽  
Simultaneous Estimation ◽  
Genetic Trend ◽  
Traditional Methods ◽  
Breeding Values ◽  
Value Estimation ◽  
The Uk

Best Linear Unbiased Prediction (BLUP) is now the method of choice for the estimation of breeding values in dairy and beef populations. The advantages of this mixed model methodology over traditional methods are well documented and include the simultaneous estimation of fixed effects and prediction of random effects and the utilization of records from all relatives to predict an individuals breeding value. In addition, account is taken of genetic trend and of reduction in genetic variance due to selection. In Canada, BLUP is now used for breeding value estimation of pigs but the structure of the Canadian pig industry is one of many herds practising selection with the herds linked by a widespread use of artificial insemination. The advantages of BLUP have not been investigated for the situation of the UK pig industry where most selection is performed within closed nucleus herds.The objectives of this study were to use computer simulation to determine rates of response, accuracy of prediction and accummulation of inbreeding for pigs in closed nucleus herds when selection decisions were based on estimated breeding values (EBVs) derived from BLUP compared to more traditional methods of phenotypic selection and index selection.

scholarly journals A Combined Analysis in Complementary Progeny Tests: Effects on breeding value accuracies

2016 ◽  
Vol 65 (1) ◽  
pp. 38-48 ◽  
Author(s):  
Eduardo P. Cappa ◽  
Michael U. Stoehr
Keyword(s):  
Mixed Model ◽  
Breeding Value ◽  
Forward Selection ◽  
Combined Analysis ◽  
Breeding Values ◽  
Mixed Model Approach ◽  
Additional Information ◽  
Genetic Entry ◽  
Sib Families ◽  
Progeny Tests

Abstract Complementary progeny tests allow for simultaneously ranking parents for their general combining ability (GCA) and within-family forward selection. To do this, progeny tests are established with different types of genetic entries (i.e., half-sib and full-sib seedlings, respectively), and different experimental designs. This study proposes a combined analysis of the GCA and full-sib (FS) tests using the mixed model approach to predict simultaneously the breeding values of grandparents, parents, full-sib families and offspring on the same scale. Moreover, a first order autoregressive spatial mixed model for the GCA tests was also implemented in the combined analysis. Our empirical study in coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) shows that additional information provided from relatives and the overlap genetic entry among GCA and FS tests via the proposed combined analysis, improves the accuracies of breeding values compared to the non-combined analysis. The improvements in the accuracies of breeding values for backward and forward selections were generally modest. Spatial and combined analyses gave slightly better results than the non-spatial combined model.

Mathematical methods in the breeding evaluation of small  horned ruminants

2019 ◽  
Vol 14 (3) ◽  
pp. 101-110
Author(s):  
K. A. Katkov ◽  
L. N. Skorykh ◽  
V. S. Pashtetsky ◽  
P. S. Ostapchuk ◽  
T. A. Kuevda
Keyword(s):  
Statistical Methods ◽  
Mixed Model ◽  
Statistical Tests ◽  
Live Weight ◽  
Breeding Value ◽  
System Of Equations ◽  
Data Set ◽  
Breeding Values ◽  
Genetic Groups ◽  
Biometric Model

Aim. Traditionally, prediction of breeding values of male small horned ruminants   (rams) by referring to levels of economically useful traits of their progeny is carried  out by methods of statistical analysis. However, at the same time, there is a forecasting method based on the use of a mixed biometric model. The solution of the system  of equations constituting a mixed biometric model is associated with certain difficulties caused by the peculiarity of the system matrix. It is proposed to use integrated  mathematical packages in the forecast, by which the system of equations can be  solved in several ways, followed by analysis of the results. The prediction of progeny  values is carried out by statistical methods using three statistical tests, as well as with  the use of a mixed biometric model. It is of interest to compare estimates obtained  by using statistical methods with estimates using a mixed biometric model. Material and Methods. The initial data set was the live weight of Qigai rams, the  progeny of a group of sixteen rams belonging to eight genetic groups.   Results. It was found that the forecast of breeding values of each animal using a  mixed biometric model substantially clarifies the rank of each animal in the group  being evaluated.   Conclusion. The refinement of the estimation of breeding value is related to the  effects of the genetic groups to which the animals belong in the mixed model, as well  as the degree of relationship between them. Also the mixed model also allows one to  isolate environmental effects from the overall assessment. Solving the system of  equations in several ways will improve the reliability of the forecast.

scholarly journals Untersuchungen an den Ergebnissen der Zuchtwertschätzung von Holstein Bullen und Kühen in Deutschland

2003 ◽  
Vol 46 (2) ◽  
pp. 113-126 ◽  
Author(s):  
H. H. Swalve ◽  
K. Höver
Keyword(s):  
Milk Fat ◽  
Protein Yield ◽  
Breeding Value ◽  
Breeding Values ◽  
Value Estimation ◽  
Annual Trends ◽  
Estimated Breeding Values ◽  
Using Data ◽  
High Degree ◽  
Genetic Trends

Abstract. Title of the paper: Examinations using the results of breeding value estimation for Holstein sires and cows in Germany Besides for selection purposes, estimated breeding values can be used to analyze genetic trends and structures in populations. Using data of 2,440,261 cows from four regions in Germany, genetic trends for all cows under test (registered and grade) were calculated for the period of birth years 1992 to 1999. For milk, fat, and protein yield annual trends on average were 111 kg, 3.2 kg, and 3.3 kg, respectively. An analysis of the use of proven sires revealed that a relatively large proportion of bulls get second crop daughters. Most of them, however, are used in a very limited way. The differential use of sires by breeders besides production is highly influenced by type proofs although in this respect clear differences exist between regions. An analysis comparing first proofs of young bulls with their later proofs based on additional second crop daughters for all German Holstein breeding organisations showed a high degree of agreement between the two proofs. However, this analysis was based on only 127 sires that were used more widely (plus > 500 second crop daughters).

Mixed model procedures for the Australian beef industry. 1. Multiple-trait model for estimation of breeding values for 200-day and final weights of cattle

1985 ◽  
Vol 36 (3) ◽  
pp. 527 ◽  
Author(s):  
H-U Graser ◽  
K Hammond
Keyword(s):  
Maternal Effects ◽  
Fixed Effects ◽  
Mixed Model ◽  
Growth Traits ◽  
Breeding Value ◽  
Relationship Matrix ◽  
Beef Industry ◽  
Multiple Trait ◽  
Breeding Values ◽  
Numerator Relationship Matrix

A multiple-trait mixed model is defined for regular use in the Australian beef industry for the estimation of breeding values for continuous traits of sires used non-randomly across a number of herds and/or years. Maternal grandsires, the numerator relationship matrix, appropriate fixed effects, and the capacity to partition direct and maternal effects are incorporated in this parent model. The model was fitted to the National Beef Recording Scheme's data bank for three growth traits of the Australian Simental breed, viz 200-, 365- and 550-day weights. Estimates are obtained for the effects of sex, dam age, grade of dam, age of calf and breed of base dam. The range in estimated breeding value is reported for each trait, with 200-day weight being partitioned into 'calves' and 'daughters' calves', for the Simmental sires commonly used in Australia. Estimates of the fixed effects were large, and dam age, grade of dam and breed of base dam had an important influence on growth to 365 days of age. The faster growth of higher percentage Simmental calves to 200 days continued to 550 days. Estimates of genetic variance for the traits were lower than reported for overseas populations of Simmental cattle, and the genetic covariance between direct and maternal effects for 200-day weight was slightly positive.

scholarly journals Untersuchungen zur Mortalität von Legehennen gehalten in Einzel- und Gruppenkäfigen

2005 ◽  
Vol 48 (4) ◽  
pp. 404-411
Author(s):  
N. Mielenz ◽  
M. Schmutz ◽  
L. Schüler
Keyword(s):  
Animal Model ◽  
Genetic Parameters ◽  
Laying Hens ◽  
Laying Hen ◽  
Breeding Value ◽  
Breeding Programme ◽  
Threshold Models ◽  
Breeding Values ◽  
Value Estimation ◽  
Commercial Breeding

Abstract. Title of the paper: Mortality of laying hens housed in single and group cages This study provides genetic parameters for mortality of laying hens estimated with linear and threshold models. Records of one line from a commercial breeding programme of White Leghorns from three generations were available. Data included observations of 8636 hens from single and from 6908 hens of group cages. Mortality was defined as death in the first six months of lay with dead=1 and alive=0. The average mortality was 3.3% in single and 6.3% in group cages. The binary traits were analysed separately by linear animal (LAM), by threshold animal (TAM) and by threshold sire models. Further the two mortalities were analysed together by a linear-linear animal (LLAM) and threshold-threshold animal model (TTAM). The LLAM estimates of heritability were 1.5% for single and 3.2% for group cages. The heritability estimates of TTAM ranged from 9.6% to 9.9%. The rank correlations between breeding values of LAM and TAM were for all sires, the 10% best and the 5% best sires in the range 0.96 to 1.00. The analysis of rank correlations of the linear and threshold models showed: The LLAM provides a good (but only suboptimal) alternative for breeding value estimation of mortality in the investigated laying hen population.

scholarly journals Genetische Analyse von Klauenmaßen aus der Eigenleistungsprüfung von Jungbullen

2003 ◽  
Vol 46 (2) ◽  
pp. 155-165
Author(s):  
D. Hinrichs ◽  
T. O. Kuhlmann ◽  
E. Stamer ◽  
E. Kalm
Keyword(s):  
Fixed Effects ◽  
Performance Test ◽  
Rank Correlation ◽  
Breeding Value ◽  
Dorsal Wall ◽  
Breeding Values ◽  
Black And White ◽  
Genetische Analyse ◽  
Value Estimation ◽  
Holstein Bulls

Abstract. Title of the paper: Genetic analysis of claw measurements from the performance test of young bulls The present study deals with the analysis of the claw measurements length of dorsal wall, length of heel, high of heel, diagonal, angle of dorsal wall and hardness of claw horn from the performance test of young bulls. Data collection take place at one fore leg and one hind leg from 798 young German Holstein bulls (black and white, red and white) and 89 young Angler bulls. The analysis of the systematic fixed effects was followed by the estimation of genetic parameters. A breeding value estimation was done with some of the claw traits and rank correlation for the breeding values of the claw traits and some official exterieur breeding values and the length of productive life were calculated. Heritabilities ranked from 0.00 (hardness of claw horn, upper point of measurement of hind leg) to 0.45 (diagonal of the foreleg). Genetic correlation between fore leg and hind leg vary between 0.14 and 0.99. Rank correlation of the claw trait breeding values ranked from –0.65 to 0.64. Rank correlation between official breeding values and claw trait breeding values vary from –0.27 to 0.37.

scholarly journals Stochastic simulation of the influence of insemination on the estimation of breeding value and its reliability

2008 ◽  
Vol 52 (No. 8) ◽  
pp. 236-248
Author(s):  
Z. Veselá ◽  
J. Přibyl ◽  
L. Vostrý ◽  
L. Štolc
Keyword(s):  
Stochastic Simulation ◽  
Breeding Value ◽  
Average Value ◽  
Basic Set ◽  
Value Estimation ◽  
Indirect Consequence ◽  
Single Use ◽  
Successive Generations ◽  
The Impact ◽  
The Relationship

Insemination is used less commonly in the population of beef cattle than in dairy cattle. As a consequence, herds are genetically isolated and their comparison is difficult. The objective of the paper was to evaluate the impact of the use of reference sires in insemination on the estimation of breeding value and its reliability by means of stochastic simulation based on a single addition of calves to the basic set. Simulation was divided into three variants according to the connectedness calves through sires (variant 1 – unrelated calves, variant 2 calves related between HYS but unrelated within HYS, variant 3 – calves related within and between HYS). The degree of connectedness was determined by computation of genetic drift variance (GDV). The average value of GDV in the basic set was 0.71. In our study the highest values of GDV were reached in simulated variant 3, in which the relationship increased not only between HYS but also within HYS. The lowest values of GDV were in variant 2, when the relationship increased only between HYS (simulated calves after reference sires did not have any half-sibs in HYS). The single use of reference sires in one generation to make herds connected slightly increased the average coefficient of reliability from 0.121 to 0.145 (by 2.4%) in the whole set. But this increase from 0.24 to 0.33 (by 8.9%) was observed only in animals that were directly connected through reference sires. The increase in reliability was mainly due to an increase in the number of contemporaries. A decrease in the effective number of sires’ offspring was an indirect consequence of the increase in the connectedness of the set and higher use of reference sires in insemination. This is the reason why the increase in the connectedness of the set influenced the reliability of breeding value of the whole set less than we would expect. The use of reference sires influenced the fluctuation of breeding values. The use of a higher number of reference sires in insemination with only one offspring in each of the connected herds appeared as the most suitable approach from the aspect of the connectedness of the set and reliability of breeding value estimation. A marked influence of herd connectedness on the estimation of breeding value and its reliability, and on the result of breeding, is to be expected after reference sires have been used in several successive generations.

scholarly journals Evaluation of Hungarian Sporthorse mare performance tests

2010 ◽  
pp. 83-87
Author(s):  
János Posta ◽  
István Komlósi ◽  
Sándor Mihók
Keyword(s):  
Variance Components ◽  
Fixed Effects ◽  
Movement Analysis ◽  
Breeding Value ◽  
Performance Tests ◽  
Breeding Values ◽  
Movement Index ◽  
Value Estimation ◽  
The Mean ◽  
Trait Group

Results of the Hungarian Sporthorse mare performance tests were evaluated. Data from the period of 1993-2009 were used, coveringscores of 618 3-year-old and 310 4-year-old mares, 109 of them were tested at both ages. Seventeen traits were scored on the tests, whichcovered ten conformational, three free jumping performance and four movement analyses traits, respectively. Breeding value estimation wasbased on BLUP animal model. Test year, age and owner were included in the model as fixed effects. Variance components were estimatedwith VCE-6 software package. Heritabilities ranged from 0.32 (frame) to 0.50 (saddle region) for conformation traits, from 0.39 (jumpingstyle) to 0.49 (jumping ability and jumping skill) for free jumping traits and from 0.20 (walk) to 0.48 (canter) for movement analysis traits.Breeding value indexes were constructed for each trait group. Conformation index was computed based on the weighted scores of thebreeding values of conformational traits. The conformational score scales were used as weightings. Free jumping and movement indexescontain the proper breeding values with equal weights. A total index was also constructed using conformation index, two times the freejumping index and two times the movement index. Each breeding values and breeding value indexes were presented with the mean 100 andstandard deviation of 20 for the easier understanding.

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