Transcript DNA Parentage Testing Ranch Setting

How Do I Decide What Traits
are Important?
Carcass/Ultrasound EPDs
Bob Weaber
GRA-Cornell Univ. Animal Breeding Group
[email protected]
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
1
Overview
 Which
trait should be used in making
selection decisions?
 Ultrasound
or Carcass
 The
value of ultrasound records
 Overview of various breed
carcass/ultrasound genetic evaluations
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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Alternate Production
Circumstance
 Feedlot
owner buying bulls for the
production of forward contract weanling
cattle
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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Example Feedlot Goal
 Maximize
the income from beef
(carcass) less the production costs
 Production
costs include weanling
purchase price and per diem feeding costs
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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Example List of Traits
 Carcass
attributes
(eg carcass marbling)
 Ultrasound attributes
(eg ultrasound marbling)
 Days to finish
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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Example Relative Emphasis

What is the increase in carcass value from a
unit change in marbling score, all other traits
(in the list) held constant ?
 What is the increase in carcass value from a
unit change in ultrasound score, all other
traits (such as carcass marbling) held
constant ?
 What is the increase in costs from an extra
day on feed ?
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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The Answer
 Ultrasound
attributes have no value in
themselves when the income is
determined by the corresponding
carcass attribute and the ultrasound
phenotypic measures have been used
in the multiple trait assessment of
carcass attributes
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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The value of ultrasound
records
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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Genetic Correlations

Carcass traits



Ultrasound



Economically relevant
Observed in fed steer and heifer carcasses
Indicator
Observed on yearling breeding stock
Genetic correlation links them


Want genetic predictors for carcass trait
Have (most) phenotypes on indicator trait
Brown Bagger – Beef Cattle Genetics:
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Genetic correlations
Ultrasound
Trait
Live Wt
Bull FAT
Bull REA
Bull IMF
σp
h2
82.3
0.055
1.17
0.522
0.47
0.53
0.37
0.47
Correlated
Carcass Trait
HCW
FAT
REA
MARB
rg
0.77
0.79
0.80
0.74
SE (h2) < 0.07, SE (Rg) < 0.13
Crews et al. 2003a
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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Why should we use
ultrasound data?

Strong, positive genetic correlations


High heritabilities


Opportunity for rapid genetic change
Phenotypic record collection cost


Suggests a high proportion of the same genes
affect both traits
Carcass ~ $100 vs. Ultrasound ~ $15
New records (2003):


Angus: 4,290 carcass, 88,167 ultrasound
Simmental: 724 carcass, 4,426 ultrasound
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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Relationships
Observed Carcass Data
Carcass EPD
Progeny
Carcass
Attributes
Observed Ultrasound Data
Enns, 2003
Ultrasound EPD
True Carcass Attribute
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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Options
 EPD
calculated using carcass data
 EPD calculated using ultrasound data
 Carcass EPD calculated using carcass
and ultrasound data
 Ultrasound
 Indicator
data is useful
trait
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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Does it work?



Devitt and Wilton (2001) suggested the use of
yearling bull ultrasound measures for genetic
improvement of steer progeny carcass traits.
Selection of high- and low-line IMF phenotype
sires randomly mated resulted in significant
differences in progeny USDA QG. (Sapp et al.
2002)
Inclusion of ultrasound data in multiple trait
evaluation improves accuracy of carcass EPD,
especially for replacements with only an
ultrasound observation. (Crews and Kemp, 2002;
Crews et al., 2003b)
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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Current Carcass/Ultrasound
Genetic Evaluations
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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Current Genetic Evaluations
Breed
Angus
Carc Ultra C-U
Traits Reported
only only MT Traits Not Reported
P
Brangus
Charolais
Gelbvieh
P
P
UREA, UFT, %IMF
P
P
Hereford
Limousin
*Working to incorporate carcass
data, Spring 2004 release
CWT, MARB, REA, FT, %RP
%IMF, UREA, UFT, URFT, U%RP
CWT, MARB, REA, FT
CWT, MARB, REA, FT
P*
UREA, UFT, %IMF
P
CWT, MARB, REA, FT
%IMF, UREA, UFT
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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Current Genetic Evaluations
Breed
Carc Ultra C-U
only only MT
Traits Reported
Traits Not Reported
Maine-Anjou
P*
Red Angus
P
Salers
P*
CWT, MARB, REA, FT, %RP
SCWT, %IMF, UFT, UREA
Shorthorn
P*
CWT, MARB, REA, FT, %RP
SCWT, %IMF, UFT, UREA
Simmental
P*
CWT, %RP, MARB, FT, REA
SCWT, %IMF, UFT, UREA
*Multi-breed model
CWT, %RP, MARB, FT, REA
SCWT, %IMF, UFT, UREA
REA, MARB, FT
%IMF, UREA
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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Which EPDs do I use?

Angus

Older animals
Compare accuracy values from each evaluation




Young animals with own ultrasound observation or
those with low carcass EPD accuracies


If very different use EPDs with highest accuracy
If similar use Carcass EPD given similar percentile rank as
Ultrasound EPD
Else, use Ultrasound EPD
Ultrasound EPDs
Other breeds

Use reported EPDs
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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Selected References






Crews, D. H., Jr. and R. A. Kemp. 2002. Genetic evaluation of carcass
yield using ultrasound measures on young replacement beef cattle. J.
Anim. Sci. 80:1809-1818.
Crews, D. H., Jr., E. J. Pollak, R. L. Weaber, R. L. Quaas, and R. J.
Lipsey. 2003. Genetic parameters for carcass traits and their live
animal indicators in Simmental cattle. J. Anim. Sci. 81:1427-1433. 242
Crews, D. H., Jr., E. J. Pollak, R. L. Quaas. 2003. Evaluation of
Simmental carcass EPD estimated using live and carcass data.
Submitted J. Anim. Sci.
Devitt, C. J. B, and J. W. Wilton. 2001. Genetic correlation estimates
between ultrasound measurements on yearling bulls and carcass
measurements on finished steers. J. Anim. Sci. 79:2790-2797.
Sapp, R. L., J.K. Bertrand, T. D. Pringle, and D. E. Wilson. 2002.
Effects of selection for ultrasound intramuscular fat percentage in
Angus bulls on carcass traits of progeny. J. Anim. Sci. 80:2017-2022.
Wilson, D. E. 1992. Application of ultrasound for genetic improvement.
J. Anim. Sci. 70:973-983.
Brown Bagger – Beef Cattle Genetics:
Fine Tuning Selection Decisions
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