Interbull production and type (MACE) proofs became official in February 2001, replacing the outdated conversion formulae method.
What Does MACE mean?
Multiple-Trait Across Country Evaluations
Why MACE?
The February 2001 genetic evaluations represented a major step forward in the
international comparison of bulls for Type Traits. The MACE procedure, which is already in use
in most other countries will be utilised to combine both foreign and domestic
information. This will mean that all bulls are directly comparable for all type proofs on a UK
basis.
Globalisation of Dairy Cattle Breeding has provided farmers in the UK with genetic material
from all around the world. In response to these developments, there has been an increase in the demand for information
regarding the performance of both animals and the genetics from the exporting
countries. Considerable effort has been made to develop a system, which provides a multiple-trait across country
evaluation, which allows for ranking of all bulls on a countries own base. MACE is particularly useful because bull
evaluations are allowed to rank differently in each country. The conversion formulae, which have been used
previously, assume that all bulls rank the same in all countries.
The MACE procedure utilises relationships among all bulls. For example a half or full brother in one
country will contribute information to his brothers' proof in other
countries. For bulls that have no UK
daughters, the MACE system will combine the UK pedigree index together with the
foreign bull's proof, which is an improvement over the current method used of
direct conversion. Simultaneous analysis of information from multiple countries is therefore possible and not just for
two, which was a limitation with conversions.
Summary of why the changes have been made
1) Conversion formulae are based on a highly selected group. Interbull uses information on
male relatives allowing unselected sires to contribute.
2) Conversion formulae are based on relatively small numbers of bulls. Biased proofs can have
large impacts. I/B uses younger sires. E.g. 1st-crop ¾ sibs in both countries. Excludes older sires that may not be relevant in
current population. TCS systems may have been modified.
3) MACE allows simultaneous analysis of information, which overcomes the problems
experienced in converting dual sampled sires.
4) In MACE, relationships between animals are
correctly accounted for.
5) Interbull produce a Foot & Leg composite based on the foreign country Foot & Leg
composite – this appears to offer a massive improvement over the current Foot
& Leg composite used for foreign sires.
6) The Industry agreed MACE linears are more accurate than converted linears.
The four composites and TM will be produced as follows:
Body/Dairy Composite
These traits are not scored universally so Interbull do not produce composites for
these traits, thus: They must be calculated from MACE linears. This
is the same procedure as is currently used to produce composites from converted
proofs.
Foot & Leg Composite
The Foot & Leg score produced by Interbull will be used. Adopting
this composite enables a new method of TM prediction. N.B.
Italy does not have a F&L composite, so it must be predicted from Foot Angle
and Rear Leg Side.
Mammary Composite
This composite will be calculated from the MACE linears. Mammary
composite is a subjective trait, composed differently in each country.
By calculating the composite from the MACE linears it allows the traits that are
included in the composite to be determined by us, not each individual
country.
Type Merit
Type Merit will be calculated by weighting the four composites.
WHY? TM produced by Interbull from country of origin TM – highly subjective, and there
are large differences between countries. Both of the Foot & Leg linears describe shape not functionality so both are
poorly correlated with Foot & Leg composite and Type Merit. Any Type Merit
prediction made directly from linears would have a low F&L component. It
will be easy to control Type Merit if the weights on the composites are
altered.
TM Weightings
The weights used to determine TM from four composites are the same as the weights
used to determine final score from the four composites for females, these
are:
20% Body Conformation
20% Dairy Character
20% Legs and Feet
40% Mammary
These weightings are applied before the composites are scaled.
Which proof to publish (type only)
Bulls who were solely or part tested abroad and actual UK proof rel < 80% – use
MACE proof.
All bulls with actual UK proof rel >=80% use actual UK proof.
Bulls who only have daughters in UK (I.e. UK progeny tested sires) - use actual UK
proof
An 80% reliability is equivalent to about 45 effective daughters.
The 80% reliability threshhold was chosen because:
If the sire may have information in the UK that wouldn’t be contributing to
Interbull proof until proof Rel >85% at least. Effectively this information
would not be used anywhere.
If level is higher, it may delay any UK information being seen by one or more proof
runs.
Summary of Publishing Rules:
Publish actual UK proofs for bulls with daughters only in UK or where UK proof
reliability > =80%
Publish:
MACE linears
MACE F&L composite
Body / Dairy composite calculated from MACE linears
Mammary composite calculated from MACE linears.
TM calculated by weighting four composites.
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