Page 10 - Brackenfield Angus Catalogue ebook

Calving Ease EBVs (%) are based on calving difficulty scores, birth
weights and gestation length information. More positive EBVs are
favourable and indicate easier calving.
CE % Direct = Direct Calving Ease - The EBV for direct calving ease
indicates the influence of the sire on calving ease in purebred females
calving at two years of age.
CE % Daughters = Daughters’ Calving Ease - The EBV for daughters’
calving ease indicates how easily that sire’s daughters will calve at two
years of age.
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
10 BRACKENFIELD