Page 12 - Tarangower Angus Catalogue ebook

ESTIMATED BREEDING VALUES (EBVS) EXPLAINED

EBVS Whilst EBVs provide the best basis for the comparison of the genetic
An animal’s breeding value is its genetic merit, half of which will be merit of animals reared in different environments and management
passed on to its progeny. While we will never know the exact breeding conditions, they can only be used to compare animals analysed within
value, for performance traits it is possible to make good estimates. the same analysis. Consequently, TACE EBVs cannot be validly
These estimates are called Estimated Breeding Values (EBVs). compared with EBVs for any other breed.
In the calculation of EBVs, the performance of individual animals within Although EBVs provide an estimate of an animal’s genetic merit for
a contemporary group is directly compared to the average of other a range of production traits, they do not provide information for all
animals in that group. A contemporary group consists of animals of the traits that must be considered during selection of functional
of the same sex and age class within a herd, run under the same animals. In all situations, EBVs should be used in conjunction with
management conditions and treated equally. Indirect comparisons visual assessment for other traits of importance (such as structural
are made between animals reared in different contemporary groups, soundness, temperament, fertility etc). A recommended practice is to
through the use of pedigree links between the groups. 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 expressed in the units of measurement for each particular
trait. They are shown as + ive or - ive differences between an individual EBVs are published for a range of traits covering fertility, calving
animal’s genetics difference and the genetic base to which the animal ease, milking ability, growth, carcase merit and feed efficiency. When
is compared. For example, a bull with an EBV of +50 kg for 600-Day using EBVs to assist in selection decisions it is important to achieve a
Weight is estimated to have genetic merit 50 kg above the breed base balance between the different groups of traits and to place emphasis
of 0 kg. Since the breed base is set to an historical benchmark, the on those traits that are important to the particular herd, markets and
average EBVs of animals in each year drop has changed over time as environment. One of the advantages of having a comprehensive
a result of genetic progress within the breed. range of EBVs is that it is possible to avoid extremes in particular traits
and select for animals with balanced overall performance.
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.