Transcript Feed efficiency

Feed Efficiency
Genetic Projects
Terms
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Gain/Feed = Feed Efficiency
FE
Feed/Gain = Feed Conversion FC: -FE
Residual Feed Intake
RFI
Net Feed Intake
NFI:-RFI
Effects of Selection for FE or FC
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 Size at given age
 Gain
 Muscle
 Fat: External and
Intramuscular
 Must measure
individual intake
Dave Kirschten, Cornell University
Residual Feed Intake
• Observed DMI – Expected DMI
 Expected DMI given f(weight.75,ADG)
  = Favorable
Dave Kirschten, Cornell University
Response to Selection for RFI
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 Intake
 Gain, Test Weight
 Weaning Weight, Yearling Weight of Progeny
 Lean Percent
 Marbling
 Feed Efficiency
 Must measure
individual intake
Dave Kirschten, Cornell University
Indicator Traits
Useful when the ERT, is:
1 - difficult to measure,
2 - expensive to measure, or
3 - measured late in life.
Option: not measure the trait but provide
evaluations based on associated information
Evaluations
Weight
Measurements
Genetic evaluation
system
EPD’s for
Mature
Size and
Milk
Pedigree
Use mature size and milk EPD’s  Cow
Maintenance Requirement EPD’s - Evans et. al.
Another Option
Use data on related traits (indicators) to
predict the EPD’s for the ERT.
Evaluations
Weight Traits
Carcass Traits
Genetic evaluation
system
Pedigree
Herring and Bertrand
EPD’s for Feed
Efficiency
Another Option
Use data on related traits (indicators) to
predict the phenotype for the ERT.
Evaluations
Data
Biological Model
e.g. Cornell Value Discovery System
Predicted
Data
Phenotypes
Genetic evaluation
system
Pedigree
EPD’s
Predicted Phenotypes
The CVDS can be used for feedlot animals
(carcass and feedlot data) as well as breeding
animals (ultrasound and ranch data).
Predicted Phenotypes
Sire
Slaughter
progeny
Seedstock
progeny
Opportunity for “large” volumes of data!
Multiple Trait Approach
Slaughter progeny
Exactly the carcass / ultrasound model!!
Both
Seedstock progeny
Project: Heritability
Danny’s group has been working with the Jorgenson herd on
predicting the Dry Matter Requirements (PDMR) of bulls on test.
The PDMR has been obtained on 747 performance tested bulls
during those three years and these bulls were themselves progeny of
84 sires.
Heritability:
PDMR = .32
ADG = .36
Project: Heritability
Collaborative project with breed associations to collect data on
individual bulls on performance tests.
Data from Circle A ranch in Missouri.
Objective: Estimate the heritability of PDMR and the genetic
correlations between PDMR and other traits.
Project: Texas A&M, King
Ranch, NBCEC, Texas CF, and
NCBA checkoff dollars
CG of Calves
produced at the
King Ranch
Group to Texas
A&M for individual
feeding, intense
data collection and
evaluation.
Group kept at King
Ranch and pen fed.
Data collected to meet
the requirements of the
CVDS