BOLT
EPDs are only achievable by
collecting many phenotypic
records on offspring.
7.
How do we know
predictions via BOLT
are better than the
previous system
(Cornell software)?
or unfavorable direction in
a number of EPDs. Because
indexes are comprised of several
EPDs, even though movement
in individual EPDs may be
considered small, movement in
the same direction across EPDs
may yield sizable movements
in the index value. This is
particularly true for animals
that have consistent
movement in traits that are
drivers of a particular index.
Though in a large population
like ours we would expect
to see several animals
The IGS evaluation team
has conducted a series of
validations to compare the
BOLT system to the Cornell
system. BOLT-derived EPDs
had higher correlations to
birth, weaning and yearling
weights (0.34, 0.29, and 0.26,
respectively) than the Cornell
derived EPDs (0.27, 0.19, and
0.20, respectively). Furthermore,
there was a larger difference in
average progeny performance
(birth, weaning, and yearling)
of the top 1% compared to
the bottom 1% animals in the
BOLT derived EPDs compared
to the Cornell calculated EPDs.
Both validations suggest
the BOLT EPDs align better
with the actual phenotypes
than the Cornell EPDs.
8. Why do some animals
have substantial changes
in their indexes?
Though the correlations
between the previous (Cornell
derived) EPDs/indexes and the
BOLT derived EPDs/indexes are
relatively strong, there will be
some animals that happen to
move in a consistently favorable
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