Page 32 - Colvend Catalogue eBook

in fat distribution on a standard 300 kg carcase. Sires with low,
or negative, fat EBVs are expected to produce leaner progeny
at any particular carcase weight than will sires with higher EBVs.
Retail Beef Yield EBV (%) indicates genetic differences
between animals for retail yield percentage in a standard 300
kg carcase. Sires with larger EBVs are expected to produce
progeny with higher yielding carcases.
Intramuscular Fat EBV (%) is an estimate of the genetic
difference in the percentage of intramuscular fat at the 12/13th
rib site in a 300 kg carcase. Depending on market targets,
larger more positive values are generally more favourable.

SELECTION INDEXES
Self Replacing Index ($) - Estimates the genetic differences
between animals in net profitability per cow joined for an
example commercial self replacing Shorthorn herd targeting
the production of pasture finished steers. Steers are assumed
marketed at 545 kg live weight (300 kg carcase weight and 10
mm P8 fat depth) at 18 months of age. Daughters are retained
for breeding. This index is also suitable in situations where
Shorthorn sires are used over mixed British breed cows.
Dairy Index ($) - Estimates the genetic differences between
animals in net profitability per cow joined for an example
commercial dairy herd using Shorthorn bulls over dairy cows
targeting the production of pasture finished dairy beef progeny.
Steers and heifers are assumed marketed at 520 kg live weight
(280 kg carcase weight and 6 P8 mm fat depth) at 20 months of
age. All progeny are slaughtered with no replacement females
being retained.

INDEX VALUES ($)
Self Replacing +$64 Dairy +$36
ACCURACY
An accuracy is presented with each EBV and gives an
indication of the amount of information that has been used in
the calculation of that EBV. The higher the accuracy the less
the animal’s EBV are likely to change as more information is
analysed for that animal or its relatives. Accuracy below 75%
should be considered to be low. EBVs are provided for the
following traits.

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