The recent overhaul of the National Breeding Objective (NBO) in Australia has resulted in a significant upgrade to the genetic evaluation system used in the dairy industry. Implemented in December 2025, these changes aim to better reflect current and future milk payment systems while enhancing the overall efficiency of breeding practices.
Key Enhancements in Genetic Evaluation
The updated genetic evaluation system is designed to ensure that Australian Breeding Values (ABVs) are now based on a more relevant population. This revision means that comparisons are made against animals born in 2020, rather than the previous cohort from 2011. As a result, milk payments are now more aligned with market trends, providing a better financial foundation for dairy producers.
One of the notable changes includes the introduction of the Health Weighted Index (HWI), which is now more tailored to seasonal producers. This index incorporates factors such as calving ease and gestation length, reflecting feedback from farmers and industry stakeholders who participated in the review process.
Impact on ABV Values and Breeding Indices
While the base update has led to lower ABV values for most traits, it is important to note that animal rankings remain unaffected by this adjustment. The decrease in ABVs was anticipated when the base was updated, but the combined changes implemented in December have influenced the values of ABVs, indices, and animal rankings.
The Balanced Performance Index (BPI), HWI, and Sustainability Index (SI) have all seen slight increases. The BPI, in particular, has risen due to an adjustment in the weighting of milk prices, which increased from $6.18 per kilogram of milk solids to $8.43. Although individual bull rankings have shifted, many high-ranking bulls continue to maintain their status, albeit with some alterations in their positions.
In terms of overall type and mammary system ABVs for Holsteins and Jerseys, there has been a significant increase. This improvement stems from an expansion of the base group for type evaluation, which now includes all animals entering the genetic evaluation system. Consequently, this provides a more accurate assessment of the type merit within the population.
The Fertility ABV for Holsteins has decreased by six points, reflecting substantial genetic advancements in fertility over the past decade. In contrast, Jerseys have experienced a reduction in Milk Litres ABVs, averaging a drop of more than 200 litres.
The NBO is strategically designed to enhance net farm profit, articulated through three primary breeding indices: BPI, HWI, and SI. The objective undergoes a review every five years to ensure it adapts to the evolving needs of dairy operations, emerging knowledge, and advancements in breeding technologies.
DataGene has also refined the representation of type traits with intermediate optimums. These optimised traits now feature an “O” beside their breeding value to signify that they are approaching the ideal standard. No changes have been made to the calculation methods for type breeding values.
A new model for the Survival ABV has been introduced by DataGene, which combines both early and late survival data to provide a more accurate prediction of productive life. The impact of this model has been modest; approximately two-thirds of Holstein bulls experienced changes of less than plus or minus five ABV points for survival. Extreme fluctuations were limited to plus or minus eight ABV points, affecting less than one percent of the population. The impact on Jerseys was slightly more pronounced.
Since survival is an integral component of the three indices (BPI, HWI, SI), the new Survival ABV model has had a minor ripple effect on these breeding indices.
The NBO’s revisions mark a significant step towards a more effective and responsive breeding strategy in the Australian dairy industry, aiming to bolster profitability while aligning with modern market demands.
