Page 8 - Nethertown Angus Catalogue ebook

(negative) GL EBVs indicate shorter gestation length and therefore easier
calving and increased growth after birth.
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
6 Nethertown Angus