Page 7 - Ranui Angus Sale Catalogue eBook

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 ($’s) for a given market. They reflect both the short-term
profit generated by a sire through the sale of his progeny, and the
longer-term profit generated by his daughters in a self-replacing
cow herd. More information is available on selecting animals using
a selection index.
The Index values are derived using BreedObject technology. More
information is available from the BreedObject web site.
Self-Replacing Index ($) - 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.

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