Page 7 - Hauroko Valley Sale Catalogue eBook.pdf

CARCASE WEIGHT EBV (kg) is based on abattoir carcase records and is an indicator of the genetic
differences in carcase weight at the standard age of 750 days.
EYE MUSCLE AREA EBV (sq cm) is calculated from measurements from live animal ultrasound scans
and from abattoir carcase data, adjusted to a standard 400 kg carcase. This EBV estimates genetic
differences in eye muscle area at the 12/13th rib site of a 400 kg dressed carcase. More positive EBVs
indicate better muscling on animals. Sires with relatively higher EMA EBVs are expected to produce
better-muscled and higher percentage yielding progeny at the same carcase weight than will sires with
lower EMA EBVs.
RIB FAT AND RUMP FAT EBVS (mm) are calculated from measurements of subcutaneous fat depth
at the 12/13-rib site and the P8 rump site (from live animal ultrasound scans and from abattoir carcases)
and are adjusted to a standard 400 kg carcase. These EBVs are indicators of the genetic differences
in fat distribution on a standard 400 kg carcase. Sires with low, or negative, fat EBVs are expected to
produce leaner progeny at any particular carcase weight than will sires with higher EBVs.
RETAIL BEEF YIELD EBV (%) indicates genetic differences between animals for retail yield
percentage in a standard 400 kg carcase. Sires with larger EBVs are expected to produce progeny with
higher yielding carcases.
INTRAMUSCULAR FAT EBV (%) is an estimate of the genetic difference in the percentage of
intramuscular fat at the 12/13th rib site in a 400 kg carcase. Depending on market targets, larger more
positive values are generally more favourable.
DOCILITY EBV (%) is an estimate of the genetic differences between animals in temperament.
Docility EBVs are expressed as differences in the percentage of progeny that will be scored with
acceptable temperament (ie. either “docile” or “restless”).

Selection Indexes

There are currently two different selection indexes calculated for New Zealand Angus animals. These are
Self-Replacing and AngusPure. 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.

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