Page 12 - Puke-Nui Angus Catalogue eBook.pdf

INDEX DESCRIPTIONS Self Replacing Index (SRI)
As a rule, animals should be compared on EBVs regardless of accuracy.
However, where two animals have similar EBVs the one with higher The following three graphs reflects the relative change if the New Zealand
accuracy could be the safer choice, assuming other factors are equal. Angus Published Sires (at the Mid-August 2020 TransTasman Angus Cattle Genetic Selection of bulls using only the SRI tool will on average over
For further information please contact NZ Angus or TACE. Evaluation) were ranked on this selection index and the top 10% were used time develop a cow herd with the following:
within a breeding program. Given that the Published Sires are the sires of • Improved weaning rate through increased fertility
the next generation(s) of New Zealand Angus cattle and have more highly and easier calving
accurate EBVs (due to having progeny) than the average animal in the • A slowly decreasing cow size, milk and slowly increasing
ACC RANGE INTERPRETATION
database, these graphs represent the approximate selection response one body condition
EBV should be considered as a preliminary estimate. It could would expect to see in the breed from using this index.
less than 50% change substantially as more performance information • Progeny will be prime at a younger age for slaughter
becomes available. These characteristics are ideal for an environment where the herd is
New Zealand Angus Self-Replacing Index - Predicted Response
Medium accuracy, usually based on the animal’s own records exposed to prolonged seasonal feed deficits and feeding supplement
and pedigree. Still subject to substantial changes with more
50-74% is unlikely.
information, particularly when the performance of progeny are
analysed.
Medium - high accuracy and includes some progeny Expected Change in Individual Traits
75-90% information. Becoming a more reliable indicator of the animal’s
value as a parent.
High accuracy estimate of the animal’s true breeding value. It
more than is unlikely that the EBV will change much with the addition of
90% CEd CEm GL BW 200W 400W 600W MCW Milk SS DC Cwt EMA Rib Rump RBY IMF
more progeny data.
Above the 0 line (X axis) selects for more positive numbers and below the line selects
for more negative numbers. For some traits (e.g. growth), a positive response is
desirable and for others (e.g. days to calving), a negative response is desirable.
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