Page 11 - Brackenfield Angus Catalogue ebook

a shorter interval from bull-in date to calving and therefore higher
fertility.
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.
ANGUS 11