Page 19 - Storth Oaks Angus Catalogue ebook

group/herd have a parent in com- decisions. What are the key features of the TACE
mon with an animals in another It provides the best estimate of an analysis?
group/herd. For sires, this cross link- animal’s breeding value from the Key features of TACE include:
age is usually achieved through AI information available.
but could also be through common
dams. TACE is a useful aid to selection, not •
because you are a poor judge of Calculating breeding values for all
TACE uses “multiple trait” evaluation cattle but because when it comes to animals and all traits simultaneously,
which further increases the accuracy long term memory recall or making hence its description as a “Multiple
of the EBVs
simultaneous adjustments for known Trait Animal Model”.
Because there is usually a genetic environmental effects over a number
association between different traits of traits, human brain power is no •
(which may be positive or negative match for a computer. Using performance information from
and vary from weak to strong) this Why use TACE to analyse perfor- relatives and progeny, as well as the
information can be used enhance mance records? individual animal.
measurements of recorded traits or
estimate an animal’s breeding value What we see or measure in an animal
for traits that have not been directly is influenced by both environmental •
measured. and genetic factors. Using the known correlation be-
tween traits to increase the accuracy
For example, 200 day weight has a Environmental factors influence the of measured traits and to calculate
positive association with 400 day way an animal may look or perform EBVs for non-measured traits such as
weight – that is, as 200 day weight within a given environment but not birth weight or weight at later ages.
increases so does 400 day weight. the way his progeny will look or per-
form within a different environment.
The multiple trait analysis also helps Environmental influences include •
to reduce the “bias” which can be nutrition (differences between pad- The use of “country of origin” per-
introduced by a previous selection docks or properties, supplementary formance information of imported
decision, say selective joining or dis- feeding, or trace mineral capsules), (introduced) animals.
proportional culling. For example, management such as castration and
culling of lighter calves at weaning drenching, grooming and clipping,
will give higher group average gut-fill, ill-health, and parasites. •
400 day weight. The fact that the Adjusting for the effects of differ-
remaining animals have a higher Observed differences of performance ences of nutrition, age of dam, age
group average as a result of previous between animals resulting from of calf and management group treat-
culling is accounted for in TACE as differences in environment can be ments. These are non-genetic differ-
long as the records of the previously large, but are not inherited by their ences that will affect the observed
culled animals are included in the progeny, and as such can lead our performance of the individual but
evaluation. selection decision astray. are not passed onto its progeny.
EBVs are expressed in the same units Genetic factors are the result of
as they were measured (eg, kg) and genes inherited from the parents •
are estimated relative to the breed and are the blueprint for future Removing these biases and taking
benchmark of zero, which was estab- performance, both of the individual into account the performance of
lished at the time of the first analysis. and its progeny. other animals makes TACE predic-
tions more accurate than predictions
What does TACE do? You buy a bull not for what he
looks like but how his progeny will on visual assessment.
TACE adjusts field measurements perform. It is only when environment As well as giving you EBVs for your
(raw data) submitted by the breeder factors are either standardised or animals, TACE also plots the genetic
to calculate an estimate of the adjusted for that real genetic differ- trend for your herd. This trend shows
animals breeding value (EBV). It uses ences become apparent. you the genetic direction of your
information from the performance herd for individual traits from year to
of the individual animal as well as its TACE uses sophisticated computing year, and also lets you see the effect
relatives, and allows for differences technology to adjust for known of environmental changes such as
in environment and chance that ani- environmental effects over a number pasture improvement on your overall
mals have been exposed to and that of selection traits. herd production.
would otherwise bias our selection