Page 49 - Shian Angus Sale Catalogue eBook.pdf

EBV’s
An animal’s breeding value is its genetic merit, half of which will be passed on to its progeny. While we will never know the exact breeding value,
for performance traits it is possible to make good estimates. These estimates are called Estimated Breeding Values (EBVs).
Although EBVs provide an estimate of an animal’s genetic merit for a range of production traits, they do not provide information for all of the
traits that must be considered during selection of functional animals. In all situations, EBVs should be used in conjunction with visual assessment
for other traits of importance (such as structural soundness, temperament, fertility etc).
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 sire 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 the 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. Fore sires, this EBC 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.