Page 6 - Moanaroa Angus Catalogue 2021 ebook

Gestation Length EBV (days) is an estimate of the time from conception to the
birth of the calf and is based on AI and hand mating records. Lower (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.
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