Page 8 - Colvend Catalogue eBook

EBVs Explained

Milk EBV (kg) is an estimate of an animal’s milking ability. For
sires, this EBV indicates the effect of the daughter’s milking
ability, inherited from the sire, on the 200-day weights of her
calves. For dams, it indicates her milking ability.
Scrotal Size EBV (cm) is calculated from the circumference
of the scrotum taken between 300 and 700 days of age and
adjusted to 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 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.

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