Relative efficiency of individual selection and reference sire progeny test schemes for beef production

1980 ◽  
Vol 31 (3) ◽  
pp. 601 ◽  
Author(s):  
CA Morris ◽  
LP Jones ◽  
IR Hopkins
Keyword(s):  
Genetic Gain ◽  
Progeny Test ◽  
Progeny Testing ◽  
Selection Intensity ◽  
Individual Selection ◽  
Test Results ◽  
Genetic Progress ◽  
Test Selection ◽  
Artificial Breeding ◽  
Natural Service

Individual selection on the basis of adjusted yearling weight records (policy 1) was compared with selection of proven sires based on progeny test results ('progeny test selection'). The major assumptions in the comparisons were that herd sizes were 100 recorded cows, and that each herd used four joining groups. It was assumed that 25 herds cooperated in using two reference sires in artificial breeding to link progeny test data from young bulls in natural service, thereby increasing selection intensity without the loss in accuracy normally suffered in a single multi-sired herd. In the progeny test comparisons, preselection of young bulls for progeny testing (policy 2) was also compared with random selection among young bulls for progeny testing (policy 3). This paper contains a limited number of comparisons only, in order to indicate the possible extent of selection pressure with different policies. Comparisons in terms of annual genetic progress ranked the policies in the order 2 (greatest), 1, 3, with policy 2 being better than 3 by 90-110%. The advantage of policy 2 over policy 1 was 26-38%. In all cases, using bulls first as yearlings was preferable to 2 1/4 years in terms of annual genetic gain. With individual selection, keeping bulls for 1 year compared with 2 or 3 years had little effect on annual gain, as the rise in selection intensity balanced the rise in generation interval. Inbreeding change per year was more affected, lower rates resulting from bulls being used for 1 year only. Inbreeding rates were small with progeny test selection as described here, as long as proven sons came from young bulls as well as proven sires. The effect of selection intensity under progeny test selection with preselection becomes diluted to 25% in its contribution to annual genetic change. Thus some degree of assortative mating may be useful, or wider use of proven sires relative to young sires. With preselection the break-even number of cooperating progeny test herds was low (three herds), compared with equal rates of genetic gain from individual selection.

scholarly journals Selection intensity for milk yield in 1970—1977 in the Finnish Ayrshire

1978 ◽  
Vol 50 (6) ◽  
pp. 445-454
Author(s):  
U. B. Lindström
Keyword(s):  
Milk Yield ◽  
Genetic Gain ◽  
Genetic Change ◽  
Selection Intensity ◽  
Genetic Progress ◽  
Generation Interval ◽  
Ayrshire Breed ◽  
The Mean ◽  
Selection Differentials

Selection differentials for sires and dams of bulls taken into AI use in 1970—1977, as well as for sires used in AI, were combined with an estimate of the quality of dams of female replacements to calculate the (predicted) genetic change in milk yield in the Ayrshire breed. In the period the average annual genetic gain was 0.97 % of the mean yield, in the last three years it was c. 1.1 %. The average generation interval was 6.8 years; 8.7 years for the bull sires, 7.4 years for the bull dams and 6.4 years for the cow sires. The bull sires accounted for 42 %, the bull dams for 37 % and the cow sires for only 12% of the total genetic gain. A more rational use of progeny tested and young bulls, combined with a reduction of the generation interval of 15 %, could easily have increased the genetic progress by 20 %.

Expectation and variance of genetic gain in open and closed nucleus and progeny testing schemes

1991 ◽  
Vol 53 (2) ◽  
pp. 133-141 ◽  
Author(s):  
T. H. E. Meuwissen
Keyword(s):  
Genetic Gain ◽  
Variance Reduction ◽  
Deterministic Model ◽  
Finite Size ◽  
Response Rates ◽  
Progeny Test ◽  
Progeny Testing ◽  
Individual Record ◽  
Open Nucleus ◽  
Selection Of

AbstractOpen and closed nucleus and conventional and modern progeny testing schemes were compared for expectation and variance of genetic gain. Generation intervals were optimized, with minimum values of 2 and 6 years (progeny test results available) for males in nucleus and progeny testing schemes, respectively. Females had a minimum generation interval of 2 years, except in the conventional progeny testing schemes, which had a minimum of 4 years (one individual record available). Apart from the generation intervals and the progeny test, open nucleus and progeny testing schemes were identical, since ‘nucleus females’ are also born in progeny testing schemes, being full-sibs of the young bulls and dispersed over commercial herds. The number of nucleus sires (bull sires) selected was varied between four and 32. Selection was for milk production.A deterministic model was used, that accounted for variance reduction due to selection and the effects of finite size and family structure on the selection differentials. Prediction of the variance of the selection response accounted for selection of full- and paternal half-sibs.Closed nucleus schemes gave a factor 0·03, 0·13 and 0·19 larger response rates than open nucleus and modern and conventional progeny testing schemes, respectively. Reduction of genetic variance of open nucleus schemes was larger than that of closed nucleus schemes, which caused the slightly higher response rates of closed nucleus schemes. Standard deviations of selection responses of closed nucleus schemes were a factor 0·46, 0·79 and 0·86 larger, respectively.Preference for the schemes was assessed using a quadratic utility function expressing risk and inbreeding aversion. The increase in genetic gain due to shortening of generation intervals more than compensated for its increased variance. Whether the increased genetic gain due to closing the nucleus compensated for its increased variance depended on the amount of risk aversion. Selection of four sires and eight to 16 sires had the highest utility in progeny testing and nucleus schemes, respectively.

The progeny testing of dairy bulls—a comparison of tests on father and son

1960 ◽  
Vol 54 (1) ◽  
pp. 100-104 ◽  
Author(s):  
Alan Robertson
Keyword(s):  
Fat Content ◽  
Progeny Test ◽  
Progeny Testing ◽  
Test Results ◽  
Average Production ◽  
Ayrshire Breed ◽  
Dairy Bulls ◽  
Significant Regression ◽  
Comparison Of Tests ◽  
Father And Son

1. A comparison has been made of the progenytest figures for father and son in the Friesian breed.2. There was a significant regression of contemporary comparison of son on contemporary comparison of father (0·22) and on r.b.v. of father (16·4 lb. per unit of r.b.v.), though both figures were about one-quarter lower than expected. The observed figures were consistent with a heritability of heifer yield of 0·19. The regression of contemporary comparison of son on the average production of the herds in which his half-sibs were milked was small and not significantly different from zero.3. For fat content, the regression of son's daughter average on father's daughter average was 0·32, in agreement with expectation.4. A less-detailed analysis for the Ayrshire breed on the above points gave essentially similar results.5. The possible extent of selection on the basis of progeny-test results was looked into. For yield, the selection was small, leading to a probable improvement of 1–2 gal. a year. For fat content, the probable increase was 0·01% a year.6. A method is described for evaluating the progeny test of a son in relation to his father's own progeny-test results, which can serve as a method of combining the progeny-test figures from different bulls.

scholarly journals Genetic Gain and Diversity under Different Selection Methods in a Breeding Seed Orchard of Quercus serrata

2007 ◽  
Vol 56 (1-6) ◽  
pp. 277-281 ◽  
Author(s):  
K. S. Kang ◽  
B. H. Cheon ◽  
S. U. Han ◽  
C. S. Kim ◽  
W. Y. Choi
Keyword(s):  
Genetic Gain ◽  
Gene Diversity ◽  
Seed Orchard ◽  
Selection Method ◽  
Quercus Serrata ◽  
Selection Intensity ◽  
Individual Selection ◽  
Selection Methods ◽  
Family Selection ◽  
Status Number

Abstract Genetic gain and diversity were estimated in a 13- year old Quercus serrata breeding seed orchard under three selection (rouging) methods. The selections were based on individual selection, family selection, and family plus within family selection. Genetic gain was for stem volume and gene diversity was estimated by status number concept. Both estimated genetic gain and gene diversity were compared to those before selection and among selection scenarios. Estimated genetic gain for tree volume ranged from 4.0% to 9.1% for three selection methods under 50% selection intensity. Individual selection was better than family selection for retaining higher genetic gain and status number. Family plus within family selection was the best selection method, while individual selection was more efficient at the strong selection intensity. An optimal point, which maximized gain and diversity, was occurred at 50% selection intensity that would be applied for genetic thinning in the breeding seed orchard of Quercus serrata. The effect of genetic relatedness among families and possible pollen contamination on both genetic gain and gene diversity, although were not studied but their impact, are discussed. The selection method and intensity level applied should be chosen after careful consideration of the impacts on both genetic gain and diversity for seeds produced from the seed orchard.

scholarly journals Genomic Analysis, Progress and Future Perspectives in Dairy Cattle Selection: A Review

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 599
Author(s):  
Miguel A. Gutierrez-Reinoso ◽  
Pedro M. Aponte ◽  
Manuel Garcia-Herreros
Keyword(s):  
Dairy Cattle ◽  
Production Efficiency ◽  
Association Studies ◽  
Phenotypic Traits ◽  
Progeny Testing ◽  
Genome Wide Association Studies ◽  
Genetic Progress ◽  
Breeding Programs ◽  
Increased Risk ◽  
Selection Of

Genomics comprises a set of current and valuable technologies implemented as selection tools in dairy cattle commercial breeding programs. The intensive progeny testing for production and reproductive traits based on genomic breeding values (GEBVs) has been crucial to increasing dairy cattle productivity. The knowledge of key genes and haplotypes, including their regulation mechanisms, as markers for productivity traits, may improve the strategies on the present and future for dairy cattle selection. Genome-wide association studies (GWAS) such as quantitative trait loci (QTL), single nucleotide polymorphisms (SNPs), or single-step genomic best linear unbiased prediction (ssGBLUP) methods have already been included in global dairy programs for the estimation of marker-assisted selection-derived effects. The increase in genetic progress based on genomic predicting accuracy has also contributed to the understanding of genetic effects in dairy cattle offspring. However, the crossing within inbred-lines critically increased homozygosis with accumulated negative effects of inbreeding like a decline in reproductive performance. Thus, inaccurate-biased estimations based on empirical-conventional models of dairy production systems face an increased risk of providing suboptimal results derived from errors in the selection of candidates of high genetic merit-based just on low-heritability phenotypic traits. This extends the generation intervals and increases costs due to the significant reduction of genetic gains. The remarkable progress of genomic prediction increases the accurate selection of superior candidates. The scope of the present review is to summarize and discuss the advances and challenges of genomic tools for dairy cattle selection for optimizing breeding programs and controlling negative inbreeding depression effects on productivity and consequently, achieving economic-effective advances in food production efficiency. Particular attention is given to the potential genomic selection-derived results to facilitate precision management on modern dairy farms, including an overview of novel genome editing methodologies as perspectives toward the future.

scholarly journals Genetic progress and potential of common bean families obtained by recurrent selection

2015 ◽  
Vol 15 (4) ◽  
pp. 218-226 ◽  
Author(s):  
Anatércia Ferreira Alves ◽  
José Ângelo Nogueira de Menezes Júnior ◽  
Vanessa Maria Pereira Silva Menezes ◽  
José Eustáquio de Souza Carneiro ◽  
Pedro Crescêncio Souza Carneiro ◽  
...  
Keyword(s):  
Common Bean ◽  
Genetic Gain ◽  
Recurrent Selection ◽  
Population Cycle ◽  
Base Population ◽  
Genetic Progress ◽  
Simultaneous Evaluation ◽  
Agronomically Important Traits

Abstract The objective of this study was to estimate the genetic gain of two recurrent selection cycles in common bean breeding and identify families with the potential to generate superior lines. The base population, cycle zero (C0), was obtained by combining 20 carioca bean parents, populations with favorable phenotypes for several agronomically important traits. The parents were recombined in a circulant diallel scheme, in which each parent participated in two crosses, generating 20 populations. From these populations, families were derived and evaluated for three seasons in the generations F2:3, F2:4 and F2:5. The same procedures of recombination and evaluation in C0 were performed in cycle one (CI). The genetic gain for yield, estimated from the simultaneous evaluation of the 40 best families of each cycle, was 8.6%. Families with potential to generate superior lines to cultivar Pérola were identified, especially among the CI families.

scholarly journals Genomic Selection for Any Dairy Breeding Program via Optimized Investment in Phenotyping and Genotyping

2021 ◽  
Vol 12 ◽  
Author(s):  
Jana Obšteter ◽  
Janez Jenko ◽  
Gregor Gorjanc
Keyword(s):  
Genomic Selection ◽  
Genetic Gain ◽  
Breeding Program ◽  
Progeny Testing ◽  
Initial Training ◽  
Training Population ◽  
Breeding Programs ◽  
Use Of Resources ◽  
Dairy Cattle Breeding ◽  
Close Relatives

This paper evaluates the potential of maximizing genetic gain in dairy cattle breeding by optimizing investment into phenotyping and genotyping. Conventional breeding focuses on phenotyping selection candidates or their close relatives to maximize selection accuracy for breeders and quality assurance for producers. Genomic selection decoupled phenotyping and selection and through this increased genetic gain per year compared to the conventional selection. Although genomic selection is established in well-resourced breeding programs, small populations and developing countries still struggle with the implementation. The main issues include the lack of training animals and lack of financial resources. To address this, we simulated a case-study of a small dairy population with a number of scenarios with equal available resources yet varied use of resources for phenotyping and genotyping. The conventional progeny testing scenario collected 11 phenotypic records per lactation. In genomic selection scenarios, we reduced phenotyping to between 10 and 1 phenotypic records per lactation and invested the saved resources into genotyping. We tested these scenarios at different relative prices of phenotyping to genotyping and with or without an initial training population for genomic selection. Reallocating a part of phenotyping resources for repeated milk records to genotyping increased genetic gain compared to the conventional selection scenario regardless of the amount and relative cost of phenotyping, and the availability of an initial training population. Genetic gain increased by increasing genotyping, despite reduced phenotyping. High-genotyping scenarios even saved resources. Genomic selection scenarios expectedly increased accuracy for young non-phenotyped candidate males and females, but also proven females. This study shows that breeding programs should optimize investment into phenotyping and genotyping to maximize return on investment. Our results suggest that any dairy breeding program using conventional progeny testing with repeated milk records can implement genomic selection without increasing the level of investment.

scholarly journals Planungsrechnungen zur Optimierung von Zuchtplänen der Rasse Merinofleischschaf

1999 ◽  
Vol 42 (3) ◽  
pp. 267-280
Author(s):  
U. Müller ◽  
K. Strittmatter ◽  
G. Nitter
Keyword(s):  
Field Test ◽  
Genetic Gain ◽  
The Other ◽  
Test Scheme ◽  
Progeny Testing ◽  
Basic Scheme ◽  
Lean Meat ◽  
Meat Content ◽  
Selection Strategies ◽  
Step Selection

Abstract. Title of the paper: Alternative selection strategies for the Mutton Merino breed to optimize breedine Systems This paper deals with the investigation of alternative selection strategies for the Mutton Merino breed to improve lamb meat production and fertility. A main topic is the application of ultrasonic scanning to evaluate the meat content on live animals. The aim of model calculations was the optimisation and comparison of five different selection strategies within three different schemes of gene dissimation. First a basic scheme was defined and optimised (selection on field records, one-step selection, no scanning). It was regarded as the reference scheme to which all other breeding Systems were related. The following schemes considered both, selection with and without scanning. A second scheme, also based on field records, includes two-step selection of rams (called improved field test scheme). In a third and fourth scheme a level of uniform environment was assumed for ram progeny testing. These are a central testing Station on the one hand with slaughtering and carcass evaluation on progeny, and one or more contract farms on the other (without slaughtering). For a fifth selection scheme an open nucleus was assumed with ram progeny testing in associated test herds. In a dcterministic approach using the ZPLAN Computer program, the monetary genetic gain for the breeding objeetive (traits lambs weaned, litter weight at weaning, postweaning daily gain and lean meat content) and the profit were calculated for each scheme after optimisation of various biological-technical coefficients. The highest profit was achieved with a nucleus scheme (DM 9,16). Due to low recording costs the basic scheme was second (DM 7,19) and, because of high costs, the Station scheme was last (DM 4,22). The other two schemes were intermediate (DM 6,98 for the scheme with contract farms and DM 6,58 for the improved field test scheme). On an average over all schemes, scanning resulted in a 0,24 DM (i.e. almost 30 per cent) increase of the monetary genetic gain and a threefold higher genetic gain for lean meat percentage. In all schemes scanning lead also to a higher profit because the higher retum of selection based on scanning exceeded the higher costs.

Genetic changes in ruminants: Historic trends and future prospects

2000 ◽  
Vol 27 ◽  
pp. 29-38
Author(s):  
Brian McGuirk
Keyword(s):  
Beef Cattle ◽  
Disease Incidence ◽  
Dairy Industry ◽  
Progeny Testing ◽  
Production Traits ◽  
Genetic Progress ◽  
Genetic Changes ◽  
Frozen Semen ◽  
Type Traits ◽  
Cattle And Sheep

AbstractThe major ruminant species, dairy and beef cattle and sheep, represent a rather heterogeneous group as regards genetic improvement, which to a large extent reflects their respective breeding structures. In the UK, the beef cattle and sheep industries still span many different breeds, have small herds/flocks, and have been relatively unaffected by agribusiness investment, and are assumed to have a traditional pyramid breeding structure, in which progress is determined by a small number of breeders. Recording of production information, which to date has focussed on terminal sire characteristics, is relatively recent, and until the use of across herd evaluations, genetic progress was probably limited. However in recent years there have been gains in both growth and muscling. There is little evidence or concern for undesired consequences in commercial flocks, partly because of the extensive use of crossbreeding in these industries, which exploits both breed complementarity and heterosis.By contrast, the dairy industry is now dominated by purebred Holsteins. Increasingly breeding activities are both global in scope and dominated by a small number of large breeding companies. Because most traits of interest are only expressed in the female, improvement programmes have continued to focus on progeny testing, with test daughters in many herds. Most recording schemes and promotional activities emphasise production and type traits. The dairy industry is also notable for the publication of bull progeny test results, so that top bulls can then be used as sires of the next generation of by all companies. These bull evaluations now extend to international rankings.Data from the US indicates continuing genetic progress for production traits in the Holstein, particularly since the 1960s, by when progeny testing had been established, frozen semen widely used, and adequate statistical procedures in place for evaluating bulls. Genetic progress is also evident for type traits. There is now growing concern and evidence of undesirable genetic changes in fertility, disease incidence and overall stress, despite improved nutrition and general management. Altering this situation will require both the recording of such traits and the use of that information by breeding companies, especially in sire selection.

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