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Multiple Breed Evaluation Can MBE enhance crossbreeding?. John Pollak Cornell University Director, NBCEC. Can MBE enhance crossbreeding?. Yes. Outline: Brief overview of motivation for MB models. On the models themselves. Justification for the answer “yes.” Where are we today in MBE.

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Multiple Breed Evaluation Can MBE enhance crossbreeding?

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Multiple Breed EvaluationCan MBE enhance crossbreeding?

John Pollak

Cornell University

Director, NBCEC


Can MBE enhance crossbreeding?

Yes

  • Outline:

  • Brief overview of motivation for MB models.

  • On the models themselves.

  • Justification for the answer “yes.”

  • Where are we today in MBE.


National Genetic Program

Objective: Design a national genetic program for profitable production of beef.

What would be desirable feature of that program?


Seedstock

Genetics

The Beef Industry

Invests in information.

Wealth of opportunity for useful information for genetic improvement down stream.

Commercial

Feeders

Calves

Adaptability

Processors

Finished

cattle

Feed Performance

Consumers

Animal

Protein

Carcass

Health


National Genetic Program

  • Integrated system of data capture across all segments of the industry on sire identified animals from birth to slaughter or maturity.

    Non-traditional sources like commercial ranches and feedlots. Typically crossbred cattle.

    Barriers: Animal ID and Sire ID


National Genetic Program

  • Commercial industry that:

    • Maximizes the expression of heterosis through crossbreeding and developing composite populations.

    • Utilizes the “best” genetics from the seedstock industry regardless of breed.


National Genetic Program

  • Seedstock industry that:

    • Focuses selection decisions on economically relevant traits for the commercial industry.

    • Provides genetic assessments that are comparable across breeds.


Motivation

All require some method of assessing animals of different breeds or breed composition.

That is, all aspects of that national program could benefit from multibreed evaluation technology.


Current MBE Programs

Two programs for weight traits:

ASA/Cornell 1997

Several breed associations participate.

Georgia 2002

Single breed association evaluations with crossbreds

Both use external EPDs.

MB system for carcass traits/ultrasound at Cornell.


Motivation

Built the ASA MB-ICE for several reasons:

  • Better handle the evaluation of the composite, Simbrah.

5/8 Simmental + 3/8 Brahman

We wanted to appropriately account for the influence of different Simmental founders on the Simbrah breed.


Motivation

Built the ASA MB-ICE for several reasons:

  • Better handle the evaluation of Simbrah.

  • To provide evaluations for F1 seedstock.

Growing number of Simmental members were producing F1 bulls for sale as seedstock and we wanted to better describe the genetics of these animals.


Motivation

Built the ASA MB-ICE for several reasons:

  • Better handle the evaluation of Simbrah.

  • To provide evaluations for F1 seedstock.

  • To allow for evaluations of other composite cattle that were being reported to the ASA database.


Motivation

Built the ASA MB-ICE for several reasons:

  • Better handle the evaluation of Simbrah.

  • To provide evaluations for F1 seedstock.

  • To allow for evaluations of other composite cattle that were being reported to the ASA database.

  • If other breeds joined in we would have EPDs that were directly comparable across those breeds to enhance selection decisions of commercial cattlemen.


Motivation

Notice:

All the motivating factors for building the system relate directly to the theme of this presentation and to the theme of this BB series.


MBE Models

Arnold et al. (JAS, 1992) presented the basic animal model for multibreed evaluation.

Observation = Contemporary group effects

+

other effects (e.g. age of dam)

+

Breed effects + Breeding values

+

Non-additive effects

+

Residual

Maternal effect: include breed effects, breeding values and non-additive effects for the dam.

Foundation for both the AS/Cornell and UG multiple breed models.


MBE Models

The estimated breeding value is:

EBV = Combination of breed effects

+

random genetic effect of that animal


Multibreed Models

The nonadditive effect is to account for the effect of heterosis on performance.

e.g. compare the performance of:

Simmental calf to a F1 Simm-Angus calf in the same CG

Account for the contribution to performance from the expected heterosis in the F1 calf


Heterosis

10 Effects in the ASA/Cornell MB-ICE

Continental  ... Cont, Brit, Zebu, Other

British  ... Brit, Zebu, Other

Zebu  ... Zebu, Other

Other … Other

Could include breed specific heterosis values

(e.g. Angus with Hereford)


Heterosis

Probability alleles originate from different breeds

Charolaisx Angus= 1.00

This cross would get the full contribution of the Continental by British heterosis.

Charolaisx(1/2)A (1/2)C= 0.50

Charolaisx(1/4)A (3/4)C= 0.25


Heterosis

Charolais x (1/2)Angus (1/2)Simmental

This cross would get:

50% of the Continental by British heterosis

+

50% of the Continental by Continental heterosis


Summary

  • The motivation for developing the MB evaluations are consistent with the enhancements they would bring to crossbreeding programs.

  • An MB system allows for the opportunity to expand the scope of genetic evaluations.

  • The model for MB allows for crossbred (composite) data.


Why “Yes”

Previous comments:

The quality of the crossbred (or composite) program is a function of the quality of the parents selected as foundation animals.

EPDs, in general, allow for characterizations of foundation animals and for setting bench marks for future selections.


Why “Yes”

In cases where several breeds are joined in a multiple breed evaluation, direct comparison of the genetic merit of animals from those breeds is possible.


Why “Yes”

F1 bulls have achieved a significant level of market share.

Multiple breed EPDs allow for characterizations of the F1 animals in comparison to their purebred counterparts.


Why “Yes”

Previous comments:

One concern with composites is the lack of access to genetic evaluations.

Multiple breed EPDs allow for evaluations of composites and accounts for the differences in breed composition within the composites in both the initial stages of composite development and in some cases, at “stabilization.”


Caveat

Is our EPD an EPD?

Sire 1 DamSire 2

EPD = Expected Progeny Difference

Calf 1

Calf 2


Caveat

Is our EPD an EPD?

EPD = Expected Progeny Difference

The difference is technically in the additive genetic merit of the two calves.

However, all else equal, this is ALSO a prediction of the difference in calf performance.


Caveat

Is our EPD an EPD?

Sire 1 DamSire 2

EPD = Expected Progeny Difference

Calf 1

Calf 2

If all are the same breed then the EPD predicts both the differences in the additive genetic merit of the calves as well as the expected difference in their performance.


Economic Assessment

Predicting performance differences as a result of selection is important in the economic assessment of a selection decision.


Is our EPD an EPD?

Simmental DamAngus

Simm-Angus

Calf 1

Calf 2

In this example, the contribution of heterosis is the same regardless of choice of sire so the prediction of the performance difference is still the differences in the calves EPDs.


Is our EPD an EPD?

Simmental DamAngus

Simmental

Calf 1

Calf 2

In this case, the difference in performance is influenced by the difference in expected heterosis which is not a part of the EPD.


With the use of MBE EPDs we need to make clear in educational programs that the EPD has a specific definition.

Prediction of performance differences in calves is not a by product of the EPDs in certain cases.

Decision support tools for phenotypic prediction.

NBCEC project at CSU


NBCEC MB Prototype

We are currently in the process of researching the use of the MB model for a greatly expanded number of breeds.


NBCEC MB Prototype

  • Developing a national pedigree file

  • Developing a national database of weight records

  • Using the ASA/Cornell model for this investigation

  • Use the Georgia model for application


NBCEC MB Prototype

Current prototype run included:

ASA data (Simmental, Chianina, Maine Anjou)

Red Angus

Limousin

Gelbvieh

Charolais

Brangus

Currently loading South Devon and Saler data


NBCEC MB Prototype

Process:

“Load and run”

Each time we load a breed into the national pedigree and data files we run an evaluation.

Report “anomalies” to breed associations for review and, if necessary, correction for the next run.


NBCEC MB Prototype

Rank correlations between the within breed runs and the NBCEC prototype run are >0.9 for high accuracy bulls.

Nice check of all three systems!


NBCEC MB Prototype

Issues:

Identification across registries

Contemporary groups definitions

Adjustments to records

Data filters and edits

Breed Specific Parameters

Commercial information

Independent composite programs (e.g. Bell Ranch)


NBCEC MB

Evolution of MB programs in the NBCEC:

Cornell will run the MB weight trait prototype and take ultimate responsibilities for the national database.

Georgia is preparing a multiple breed carcass/ultrasound evaluation and random regression model for weights.

CSU is developing the web based selection decision support programs to utilize the MB EPDs.


NBCEC MB

Obviously, to provide complete profiles of potential parents we will needed to evolve all trait evaluation programs to MB.

For the cow-calf decision support program need:

Calving ease

Stayability

Cow Maintenance requirements

For the “finishing” decision support program need:

Days-on-feed

RFI?

Other Traits?


Thank you!


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