Page 37 - Tapiri Angus 2021 Catalogue ebook

UNDERSTANDING ESTIMATED BREEDING VALUES (EBVS), SELECTION INDEXES AND ACCURACY
EBVs
Calving Ease EBVs (%) are based on calving difficulty scores, birth weights 200-Day Growth EBV (kg) is calculated from the weight of progeny taken
and gestation length information. More positive EBVs are favourable and between 80 and 300 days of age. Values are adjusted to 200 days and for
indicate easier calving. age of dam. This EBV is the best single estimate of an animal’s genetic merit
CE % Direct = Direct Calving Ease - The EBV for direct calving ease for growth to early ages.
indicates the influence of the sire on calving ease in purebred females 400-Day Weight EBV (kg) is calculated from the weight of progeny taken
calving at two years of age. between 301 and 500 days of age, adjusted to 400 days and for age of
CE % Daughters = Daughters’ Calving Ease - The EBV for daughters’ dam. This EBV is the best single estimate of an animal’s genetic merit for
calving ease indicates how easily that sire’s daughters will calve at two yearling weight.
years of age. 600-Day Weight EBV (kg) is calculated from the weight of progeny taken
Gestation Length EBV (days) is an estimate of the time from conception between 501 and 900 days of age, adjusted to 600 days and for age of dam. This
to the birth of the calf and is based on AI and hand mating records. Lower EBV is the best single estimate of an animal’s genetic merit for growth beyond
(negative) GL EBVs indicate shortergestation length and therefore easier yearling age.
calving and increased growth after birth. 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
Birth Weight EBV (kg) is based on the measured birth weight of progeny, of the genetic difference in cow weight at 5 years of age and is an indicator
adjusted for dam age. The lower the value, the lighter the calf at birth and of growth at later ages and potential feed maintenance requirements of the
the lower the likelihood of a difficult birth. This is particularly important females in the breeding herd. Steer breeders wishing to grow animals out
when selecting sires for use over heifers.
to a larger weight may also use the Mature Cow Weight EBV.
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