Page 76 - Earnscleugh 2021 Catalogue eBook

SELECTION INDEXES AND ACCURACY

Accuracy
Accuracy (%) is based on the amount of performance information available Please Note:
on the animal and its close relatives - particularly the number of progeny There has been a review of Angus Indexes but with the same labelling.
analysed. Accuracy is also based on the heritability of the trait and the An explanation of the new indexes is provided in the catalogue.
genetic correlations with other recorded traits. Hence accuracy indicates In simple terms,
the “confidence level” of the EBV. The higher the accuracy value the lower The Self Replacing Index (SRI) is made to be used by properties
the likelihood of change in the animal’s EBV as more information is analysed where the herd is exposed to prolonged seasonal feed deficits and
for that animal or its relatives. Even though an EBV with a low accuracy may feeding supplement is unlikely.
change in the future, it is still the best estimate of an animal’s genetic merit The Angus Pure Index is for properties where the herd can be
for that trait. As more information becomes available, an EBV is just as likely managed with extra feed if a seasonal deficit occurs.
to increase in value, as it is to decrease. These changes have meant the averages for indexes have changed
Accuracy values range from 0-99%. significantly so index values cannot be compared with previous years.
As a rule, animals should be compared on EBVs regardless of accuracy.
However, where two animals have similar EBVs the one with higher accuracy
could be the safer choice, assuming other factors are equal.

For further information please contact NZ Angus or TACE.

74 Earnscleugh 36th Annual Sale