Page 11 - Umbrella Angus 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 ($’s) for a given market. They
reflect both the short-term profit generated by a sire through the sale of his progeny, and the longer-
term profit generated by his daughters in a self-replacing cow herd. More information is available on
selecting animals using a selection index. The Index values are derived using BreedObject technology
Self-Replacing Index ($) - 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.
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.
Accuracy values range from 0-99%. The following guide is given for interpreting accuracy:
For further information please contact NZ Angus or BREEDPLAN.

2021 TRANSTASMAN ANGUS CATTLE EVALUATION EBVS

200 Day 400 Day 600 Day
CED DTRS Gest BW Mat W MILK
Weight Weight Weight
+1.8 +2.1 -4.4 +4.2 +46 +84 +110 +95 +16

INDEXES
SS DC CWT EMA Rib Rump RBY IMF
SR AP HDT
+1.9 -4.2 +61 +5.4 +0.1 -0.2 +0.4 +1.8 +$100 +$103 +$102

11