Composite traits: a challenging definition
¾ Composite trait:
• A trait that is composed by other traits in its
computation
Composite traits and
International genetic evaluation
¾ Not to be confused when speaking of Conformation with:
• General characteristics
• Overall or Final Score
• Overall type traits
F. Canavesi, J. Pena, G. De Jong,
G. Pedersen Aamand, S. Mattalia
ICAR 2006, Kuopio, Finland
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Problems related with overall type
traits in International evaluation
Country
AUS
BEL
CAN
CHE
CHR
CZE
DEU
DFS
DNK
ESP
FRA
GBR
HUN
ITA
JPN
NLD
Overall conformation
General appearance
Overall conformation score
Final score (individual trait)
Final score (composite trait)
Overall score (composite)
Overall conformation score
Relative breeding value conformation(RZE)
Overall conformation(composite)
Overall conformation(composite)
Overall conformation (composite trait)
Overall score (composite)
Overall conformation (composite)
Overall conformation
Final score (individual trait)
Overall conformation (composite)
Overall conformation(composite)
NOR
NZL
POL
USA
Overall
Overall
Overall
Overall
conformation
conformation (composite)
conformation score
conformation (individual trait)
Overall Udder
Mammary system
Overall udder score
Mammary system
Overall udder (composite)
Composite score for udder
Overall udder score
Overall udder (composite)
Mammary (composite)
Mammary (composite)
Overall udder (composite trait)
Udder score (composite)
Overall udder (composite)
Overall udder
Overall udder (composite)
Overall udder score (individual trait)
Qualification of total udder(individual
trait)
Udder index
All traits of the udder
Overall udder score
Overall udder (composite)
ICAR 2006, Kuopio, Finland
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In principle
Overall Feet &Legs
Side view foot diagonal
Overall F&L score
F&L (individual trait)
Overall F&L (composite)
Composite score for F&L
Overall F&L score
Overall F&L (composite)
F&L (composite)
F&L (composite)
F&L (individual trait)
Locomotion
Overall F&L (composite)
Overall F&L
Functionality of F&L (individual trait)
Overall F&L (individual trait)
Functionality of F&L (individual trait)
¾ MACE international evaluation system was set up to help
breeders convert bull proofs from other countries into the
most probable proof in their country based on:
• Genetic correlations (genetic links among countries)
• Sire variances (scale of national proofs).
¾ It was developed for single linear traits
Leg index
Overall F&L score
F&L (composite)
ICAR 2006, Kuopio, Finland
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Some examples
ICAR 2006, Kuopio, Finland
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Relative weights within Total Conformation
France
Denmark
¾ Milk, fat and protein:
• The same trait is measured in the different countries;
¾ Linear conformation traits:
• Work si ongoing to harmonize trait definitition and
allow for better comparison
• As a result of this work genetic correlationa among
countries have increased over time
Udder
F&L
Capac.
Udder
Rump
F&L
Capac.
Rump
Germany
USA
¾ What happen with overall conformation?
Udder
ICAR 2006, Kuopio, Finland
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F&L
Capac.
Dairy Type
Rump
Udder
ICAR 2006, Kuopio, Finland
F&L
Capac.
Dairy Type
Rump
6
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Some facts
The “international” predictor
¾ Mattalia, 1998
• Her study showed that:
9Overall traits have lower correlation compared to
linear traits
Trait
Rg
9Domestic bulls (with daughters
Teat lenght
0.97
in the country)
Udder depth
0.96
are always favourite
Teat placement
0.94
when correlations are low
Udder support
0.89
9It is advisable to derive
Rear udder
0.88
composites from individual
Fore udder
0.87
linear traits.
¾ A composite derived nationally in order to maximize
genetic correlation with the other countries for overall
score
Overall udder
¾ This is submitted to Interbull instead of the official proofs
that has lower correlation in order to avoid unfavourable
All traits
effects on bulls converted proofs
0.83
ICAR 2006, Kuopio, Finland
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- Ø udder (6)
- Ø F&L (3)
- Rump angle
- Stature
- Rump width
- Strength
- Body depth
- Angularity
0,92
0,82
0,97
0,95
0,91
0,88
0,86
0,85
- Overall confor.
0,81
ICAR 2006, Kuopio, Finland
Interbull recommendation
The current situation
¾ For all overall traits that can be derived by single linear
traits Interbull recommend to apply the procedure
suggested by Miglior in 2004:
• Derive a composite from linear traits assigning the
most appropriate weight for the Country;
• Combine this derived composite with the overall trait
estimated by MACE;
• This give the best correlation with the future values of
the bull in the country once its proofs will be based on
real daughters.
¾ Most countries do apply Interbull recommendation
ICAR 2006, Kuopio, Finland
Ø 0,892
8
¾ Some do not and continue to discriminate some bulls
because of the use of an inappropriate tool
¾ Discussion has been ongoing but those countries do not
seem to be willing to move to a more reliable and fair
system
9
ICAR 2006, Kuopio, Finland
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What do to next
¾ As Interbull continues to compute overall type traits
because they may be the only available tools for some
countries, recommendation at all levels to always use
linear derived traits that guarantee the best correlations
across countries may speed up the process of
harmonization:
• Interbull has defined a clear best practice procedure
• Breed Association may as well endorse this
recommended procedure
• ICAR guidelines ?
ICAR 2006, Kuopio, Finland
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