Page 6 - Martin Farming Angus 2021 Catalogue eBook

A recommended practice is to firstly select breeding stock Mature Cow Weight EBV (kg) is based on the cow weight
based on EBVs and to then select from this group to when the calf is weighed for weaning, adjusted to 5 years
ensure that the final selections are otherwise acceptable. of age. This EBV is an estimate of the genetic difference
EBVs are published for a range of traits covering fertility, in cow weight at 5 years of age and is an indicator of
calving ease, milking ability, growth, carcase merit and growth at later ages and potential feed maintenance
feed efficiency. When using EBVs to assist in selection requirements of the females in the breeding herd. Steer
decisions it is important to achieve a balance between the breeders wishing to grow animals out to a larger weight
different groups of traits and to place emphasis on those may also use the Mature Cow Weight EBV.
traits that are important to the particular herd, markets Milk EBV (kg) is an estimate of an animal’s milking ability.
and environment. One of the advantages of having a For sires, this EBV indicates the effect of the daughter’s
comprehensive range of EBVs is that it is possible to milking ability, inherited from the sire, on the 200-day
avoid extremes in particular traits and select for animals weights of her calves. For dams, it indicates her milking
with balanced overall performance. ability.
Calving Ease EBVs (%) are based on calving difficulty Scrotal Size EBV (cm) is calculated from the
scores, birth weights and gestation length information. circumference of the scrotum taken between 300 and
More positive EBVs are favourable and indicate easier 700 days of age and adjusted to 400 days of age. This
calving. EBV is an estimate of an animal’s genetic merit for scrotal
CE % Direct = Direct Calving Ease - The EBV for direct size. There is also a small negative correlation with age
calving ease indicates the influence of the sire on calving of puberty in female progeny and therefore selection for
ease in purebred females calving at two years of age. increased scrotal size will result in reduced age at calving
of female progeny.
CE % Daughters = Daughters’ Calving Ease - The
EBV for daughters’ calving ease indicates how easily that Days to Calving EBV (days) indicates the fertility of
sire’s daughters will calve at two years of age. the daughters of the sire. It is the time interval between
the day when the female is first exposed to a bull in a
Gestation Length EBV (days) is an estimate of the time paddock mating to the day when she subsequently
from conception to the birth of the calf and is based on calves. A negative EBV for days to calving indicates a
AI and hand mating records. Lower (negative) GL EBVs shorter interval from bull-in date to calving and therefore
indicate shorter gestation length and therefore easier higher fertility.
calving and increased growth after birth. Carcase Weight EBV (kg) is based on abattoir carcase
Birth Weight EBV (kg) is based on the measured birth records and is an indicator of the genetic differences in
weight of progeny, adjusted for dam age. The lower carcase weight at the standard age of 750 days.
the value, the lighter the calf at birth and the lower the
likelihood of a difficult birth. This is particularly important Eye Muscle Area EBV (sq cm) is calculated from
when selecting sires for use over heifers. measurements from live animal ultrasound scans and
from abattoir carcase data, adjusted to a standard 400
200-Day Growth EBV (kg) is calculated from the weight kg carcase. This EBV estimates genetic differences
of progeny taken between 80 and 300 days of age. in eye muscle area at the 12/13th rib site of a 400 kg
Values are adjusted to 200 days and for age of dam. This dressed carcase. More positive EBVs indicate better
EBV is the best single estimate of an animal’s genetic muscling on animals. Sires with relatively higher EMA
merit for growth to early ages. EBVs are expected to produce better-muscled and higher
percentage yielding progeny at the same carcase weight
400-Day Weight EBV (kg) is calculated from the weight than will sires with lower EMA EBVs.
of progeny taken between 301 and 500 days of age,
adjusted to 400 days and for age of dam. This EBV is Rib Fat and Rump Fat EBVs (mm) are calculated from
the best single estimate of an animal’s genetic merit for measurements of subcutaneous fat depth at the 12/13-rib
yearling weight. site and the P8 rump site (from live animal ultrasound
scans and from abattoir carcases) and are adjusted to a
600-Day Weight EBV (kg) is calculated from the weight standard 400 kg carcase. These EBVs are indicators of
of progeny taken between 501 and 900 days of age, the genetic differences in fat distribution on a standard
adjusted to 600 days and for age of dam. This EBV is 400 kg carcase. Sires with low, or negative, fat EBVs are
the best single estimate of an animal’s genetic merit for expected to produce leaner progeny at any particular
growth beyond yearling age.
carcase weight than will sires with higher EBVs.

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