Page 8 - Woodbank-Matariki ebook

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.

6 Woodbank Angus & Matariki Herefords Bull Sale 2021