Page 4 - Lochburn Shorthorn Catalogue eBook.pdf

EBV’S EXPLAINED

Estimated Breeding Values (EBVs)

An estimated Breeding Value EBV is an estimate of the genetic value of that particular animal
for each trait measured.
ACCURACY
An accuracy is presented with each EBV and gives an indication of the amount of information
that has been used in the calculation of that EBV. The higher the accuracy the less the animal’s
EBV are likely to change as more information is analysed for that animal or its relatives.
Accuracy below 75% should be considered to be low.
EBVs are provided for the following traits

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

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