Page 7 - Hinewaka Shorthorns Catalogue ebook

400 days of age. This EBV is an estimate of an animal’s genetic
merit for scrotal size. There is also a small negative correlation
with age of puberty in female progeny and therefore selection for
increased scrotal size will result in reduced age at calving of female
progeny.
Days to Calving EBV (days) indicates the fertility of the daughters
of the sire. It is the time interval between the day when the female
is first exposed to a bull in a paddock mating to the day when she
subsequently calves. A negative EBV for days to calving indicates
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 650 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 300 kg carcase. This EBV estimates genetic
differences in eye muscle area at the 12/13th rib site of a 300 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 measure-
ments 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 300 kg carcase. These
EBVs are indicators of the genetic differences in fat distribution on a
standard 300 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 300 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
300 kg carcase. Depending on market targets, larger more positive
values are generally more favourable.
COMPARING EBVs:
The EBVs for Beef Shorthorns can not be compared with EBVs
for animals of another breed. They should be compared with the
current average EBVs for Australasian Beef Shorthorn shown
below.
2021 SHORTHORN BREEDPLAN AVERAGES
FOR 2019 BORN CALVES

DIR DTRS GL Birth 200 Wt 400 Wt 600 Wt McW Milk
+1.6 +1.3 -1.7 +2.9 +27 +38 +51 +44 +6
SS DtC CWT EMA Rib Rump RBY% IMF%

+1.5 -1.6 +34 +4.3 -0.2 -0.1 +0.9 +0.6
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