Page 12 - Sudeley Angus 2021 ebook

Birth Weight EBV (kg) is based on the measured birth weight of progeny, adjusted for dam age. The
lower the value, the lighter the calf at birth and the lower the likelihood of a difficult birth. This is
particularly important when selecting sires for use over heifers.
200-Day Growth EBV (kg) is calculated from the weight of progeny taken between 80 and 300
days of age. Values are adjusted to 200 days and for age of dam. This EBV is the best single estimate
of an animal’s genetic merit for growth to early ages.
400-Day Weight EBV (kg) is calculated from the weight of progeny taken between 301 and 500
days of age, adjusted to 400 days and for age of dam. This EBV is the best single estimate of an
animal’s genetic merit for yearling weight.
600-Day Weight EBV (kg) is calculated from the weight of progeny taken between 501 and 900
days of age, adjusted to 600 days and for age of dam. This EBV is the best single estimate of an
animal’s genetic merit for growth beyond yearling age.
Mature Cow Weight EBV (kg) is based on the cow weight when the calf is weighed for weaning,
adjusted to 5 years of age. This EBV is an estimate of the genetic difference in cow weight at 5 years
of age and is an indicator of growth at later ages and potential feed maintenance requirements of the
females in the breeding herd. Steer breeders wishing to grow animals out to a larger weight may also
use the Mature Cow Weight EBV.
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.

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