Page 13 - Brookwood Angus Sale 2021 ebook

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”).

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%.
As a rule, animals should be compared on EBVs regardless of accuracy.
However, where two animals have similar EBVs the one with higher
accuracy could be the safer choice, assuming other factors are equal.
For further information please contact NZ Angus or TACE.

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