Implementing recommendations from the review of the National Breeding Objective has delivered an enhanced genetic evaluation system.
Points to note:
A general drop in ABVs due to the base update
Higher values for BPI, HWI, SI (plus ranking changes)
Higher values for overall type and mammary (Holstein and Jersey)
Lower values for fertility ABV (Holsteins)
Big drop in milk litres ABV in Jerseys
Optimum breeding values identified for type traits with intermediate optimums
New model for survival ABV Enhanced genetic evaluation system.
Enhanced genetic evaluation system
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Changes have resulted in an enhanced genetic evaluation system.
Milk payments are more reflective of current and future payment systems.
The base update means ABVs are based on comparison with a more relevant population (animals born in 2020 now instead of 2011).
The Health Weighted Index is more suited to seasonal producers, with the inclusion of calving ease and gestation length.
Farmer and industry feedback and preferences were considered when formulating the updated indices.
Lower ABV values for most traits
When the base is updated without any other changes, ABV values would be expected to be lower. Animal rankings are not affected by a base update.
However, updating the base was one of several changes implemented in December 2025 so the values of ABVs and indices and animal rankings are influenced by the combined changes.
Higher values for BPI, HWI, SI
The magnitude of indices has increased slightly in all breeds. In particular, BPI values have increased, mainly due to increase weightings of milk price; from $6.18 per kg of milk solids to $8.43.
Individual bull rankings for BPI, HWI and SI have changed, but in general, high-ranking bulls continue to rank well, albeit with some reshuffling.
Changes in BPI rankings are mostly due to the changes in milk prices, particularly the change in balance of protein to fat, as well as updated feed, input and labour.
Overall type and mammary ABVs(Holsteins and Jerseys)
In Holsteins and Jerseys, the ABV values for overall type and mammary have increased noticeably.
This is because the base group for type evaluation has been expanded to provide a more representative group of animals for comparison.
Now, all animals entering the genetic evaluation system are used, providing a better estimate of the type merit of the population used in the base.
The upshot is bulls and cows are now compared to a more representative group of animals.
The result for Holsteins and Jerseys in particular is their overall type and mammary system ABVs have risen.
Fertility ABV (Holsteins)
In Holsteins, the Fertility ABV has decreased by six points – due to the base update.
This reflects exceptional genetic improvement for fertility over the past 10 years, which means the merit of the base group has improved dramatically (since the previous base update).
Milk litres ABV (Jerseys)
In Jerseys, Milk Litres ABVs have dropped on average by more than 200 litres.
National Breeding Objective
Australia’s NBO is aimed at increasing net farm profit. It is expressed through the three breeding indices – Balanced Performance Index, Health Weighted Index and Sustainability Index.
The NBO is reviewed every five years, to ensure it keeps pace with the evolving needs of dairy businesses, new knowledge and breeding technologies.
Type traits with intermediate optimums
DataGene has enhanced the expression of type traits with intermediate optimums to make it easier for people to identify animals that are close to the optimum.
Animal that are close to the optimum carry an O beside their breeding value.
There is no change to in the way the type breeding values are calculated.
New model for Survival ABV
DataGene is now using a new model for Survival ABV.
It combines both early and late survival to give a better prediction of productive life.
About two thirds of Holstein bulls changed by less than plus or minus five ABV points for survival. Extreme changes were plus or minus eight ABV points (less than one per cent of the population).
The impact was slightly greater in Jerseys.
As survival is included in the three indices (BPI, HWI, SI), the new model Survival ABV had a small flow on effect to the BPI, HWI and SI.
