The Personalised Nerstane Breeding Objective Index

Selection based on an index of all traits in the breeding objective has been proven to be the most efficient selection system. Index selection simply means that the various traits of an animal that are part of the breeding objective are combined with a consistent weighting of importance in order to determine the overall value of the animal to the breeding program. At Nerstane traits that are objectively measured or scored are combined in a calculated index value while the remaining traits are added to the overall breeding objective index during classing.

The Nerstane personalised index for measured and scored traits is designed to put the majority of selection emphasis on micron reduction at the same time as increasing fleece weight (6% gain over ten years) and addressing the wool quality traits as set out in the breeding objectives.

The visual wool quality score has been incorporated into the index to ensure that important wool quality traits that are not measured are fully considered in the selection process.

In making the final selection decision for both ewes and rams, index rank is used as the starting point. The decision to select or cull the animals will depend on its index rank and its ability to meet the stringent structural standards set by Nerstane.