Page 10 - Grampians Angus 2021 Catalogue ebook

SELECTION INDEXES
There are currently three different selection indexes calculated
for New Zealand Angus animals.These are Self-Replacing,
AngusPure and Heifer/Dairy Terminal. Each selection index
describes a different production/market scenario and relates to
a typical commercial herd in New Zealand that is targeting the
following specifications.
Index values are reported as EBVs, in units of relative earning
capacity ($’s) for a given market. They reflect both the short-
term profit generated by a sire through the sale of his progeny,
and the longer-term profit generated by his daughters in a self-
replacing cow herd. More information is available on selecting
animals using a selection index.
The Index values are derived using BreedObject technology. More
information is available from the BreedObject web site.
Self-Replacing Index ($) - Estimates genetic differences between
animals in net profitability per cow joined for a self-replacing
commercial herd, targeting the production of grass finished
steers. Steers are assumed marketed at 525 kg live weight
(280 kg carcase weight and 10 mm fat depth) at 16 months
of age.
AngusPure Index ($) – Estimates genetic differences between
animals in net profitability per cow joined for a self-replacing
commercial Angus herd, targeting the production of grass
finished steers for the AngusPure programme. Steers are
assumed marketed at 525 kg live weight (280 kg carcase weight
and 10 mm fat depth) at 18 months of age with a significant
premium paid for marbling.
Heifer/Dairy Terminal Index ($) – Estimates the genetic
differences between animals in net profitability per female joined
in an example herd where all progeny are marketed. All progeny
are marketed at approximately 510 kg live weight (280 kg
carcase weight and 7 mm fat depth) at approximately 24 months
of age.
Note that $Index values for individual animals are sensitive to the
assumptions used in the BreedObject analysis to calculate the
selection index. More information is available on the weightings
used in the New Zealand Angus Selection Indexes.
ACCURACY
Accuracy (%) is based on the amount of performance
information available on the animal and its close relatives -
particularly the number of progeny analysed. Accuracy is also
based on the heritability of the trait and the genetic correlations
with other recorded traits. Hence accuracy indicates the
“confidence level” of the EBV. The higher the accuracy value
the lower the likelihood of change in the animal’s EBV as more
information is analysed for that animal or its relatives. Even
though an EBV with a low accuracy may change in the future,
it is still the best estimate of an animal’s genetic merit for that
trait. As more information becomes available, an EBV is just as
likely to increase in value, as it is to decrease.

8 Grampians Annual Sale