Page 8 - Peters Angus 2021 Catalogue ebook

UNDERSTANDING EBVS

average EBVs of animals in each year drop has changed over time as
a result of genetic progress within the breed.
The absolute value of any EBV is not critical, but rather the differences
in EBVs between animals. Particular animals should be viewed as
being “above or below breed average” for a particular trait.
Whilst EBVs provide the best basis for the comparison of the genetic
merit of animals reared in different environments and management
conditions, they can only be used to compare animals analysed within
the same analysis. Consequently, NZ ANGUS BREEDPLAN EBVs cannot
be validly compared with EBVs for any other breed.
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). A recommended practice is
to firstly select breeding stock based on EBVs and to then select from
this group to ensure that the final selections are otherwise acceptable.
EBVs are published for a range of traits covering fertility, calving
ease, milking ability, growth, carcase merit and feed efficiency. When
using EBVs to assist in selection decisions it is important to achieve a
balance between the different groups of traits and to place emphasis
on those traits that are important to the particular herd, markets
and environment. One of the advantages of having a comprehensive
range of EBVs is that it is possible to avoid extremes in particular traits
and select for animals with balanced overall performance.
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

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