Page 11 - Sudeley Angus 2021 ebook

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ESTIMATED BREEDING VALUES (EBVS)
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, TRANSTASMAN ANGUS CATTLE
EVALUATION 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
Secure a deal with 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
STUD STOCK Anthony Cox 0272 083 071 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
LIVESTOCK MANAGER Donald Cooke 0274 730 854
sire on calving ease in purebred females calving at two years of age.
LIVESTOCK REPRESENTATIVES 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.
Bob Davidson 0274 730 806 Hayden McCarthy 0274 730 802
Will Hurst 0274 730 858 Glen Armstrong 0274 730 482 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
Robbie Reid 0274 730 868 Aaron Leckie 0274 730 808
length and therefore easier calving and increased growth after birth.

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