Page 10 - Mt Possession Angus Catalogue ebook

EBVS EXPLAINED

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).
In the calculation of EBVs, the performance of individual
animals within a contemporary group is directly
compared to the average of other animals in that group.
A contemporary group consists of animals of the same
sex and age class within a herd, run under the same
management conditions and treated equally. Indirect
comparisons are made between animals reared in
different contemporary groups, through the use of
pedigree links between the groups.
EBVs are expressed in the units of measurement for each
particular trait. They are shown as + ive or - ive differences
between an individual animal’s genetics difference and
the genetic base to which the animal is compared. For
example, a bull with an EBV of +50 kg for 600-Day Weight
is estimated to have genetic merit 50 kg above the breed
base of 0 kg. Since the breed base is set to an historical
benchmark, the 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, TACE 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.

8 Mt Possession Angus Bull Sale 2021