Introducing Feed Efficiency into the Wagyu Genetic Evaluation
Feed costs represent the single largest variable expense in Wagyu beef production, particularly in long-fed and fullblood finishing systems. Improving feed efficiency is therefore one of the most powerful levers available to increase profitability and sustainability across the Wagyu value chain.
To address this, the Australian Wagyu Association (AWA) has introduced a Net Feed Intake (NFI) WBV, providing breeders with a genetic tool to select animals that require less feed to achieve the same level of production.
The introduction of the NFI WBV reflects major advances in Wagyu-specific data availability, genomic coverage, and genetic evaluation capability that were not previously sufficient to support a reliable feed efficiency trait.
What Is Net Feed Intake?
Net Feed Intake is a measure of feed efficiency, describing how much feed an animal consumes relative to what would be expected for its level of production.
In simple terms:
- Animals with lower (more negative) NFI values consume less feed than expected based on their bodyweight and growth rate
- Animals with higher (more positive) NFI values consume more feed than expected based on their bodyweight and growth rate
Importantly, NFI is independent of growth and body size. This distinguishes it from traits such as feed intake or average daily gain, which are strongly influenced by how big or fast-growing an animal is.
Why a Net Feed Intake WBV Is Needed in Wagyu
Limitations of Traditional Growth-Based Selection
Historically, feed efficiency improvements were pursued indirectly by selecting for faster growth or heavier carcase weight. While effective in some systems, this approach has limitations in Wagyu, where:
- Extended feeding periods magnify inefficiencies
- Selection for growth alone can increase mature size and maintenance costs
- Feed intake varies widely among animals with similar growth performance
NFI allows breeders to identify animals that convert feed more efficiently without compromising growth or carcase outcomes.
Development of the NFI WBV
Phenotypic Data Collection
The NFI WBV is derived from over 2,000 controlled feed intake and performance records, typically generated in feedlot environments where:
- Individual animal feed intake is measured
- Growth rate, body weight, and other performance traits are recorded
- Environmental effects are tightly controlled
These phenotypes are critical, as feed efficiency cannot be reliably inferred from feedlot growth data because individual feed intake is not recorded in commercial pens.
Genetic Evaluation Framework
The NFI WBV is calculated using:
- Wagyu-specific genetic parameters
- A multi-trait model incorporating growth, intake, and carcase traits
- Genomic information to improve accuracy and connectivity across the population
In Wagyu, genomics plays a particularly important role, allowing feed efficiency information from a limited number of measured animals to inform predictions across a much larger population due to the high relatedness of the population.
Relationship to Other Traits
One of the defining advantages of NFI is its independence from production traits.
Under the AWA genetic evaluation:
- NFI shows minimal genetic correlation with growth traits
- NFI is largely independent of carcase weight
- Selection for lower NFI does not inherently reduce marbling, although there is a weak negative correlation
This means breeders can select for improved feed efficiency without unintended negative consequences for traits central to Wagyu value.
Interpreting the NFI WBV
Direction of Selection
- Lower (more negative) NFI WBVs are favourable
- A difference of one unit in NFI WBV represents a meaningful genetic difference in feed consumption over a standard feeding period
Breeders should focus on relative differences between animals rather than absolute values.
Accuracy Considerations
As with all WBVs:
- Accuracy reflects the amount and quality of information contributing to the estimate
- Accuracy will improve as more Wagyu feed intake data is collected
Given the cost and complexity of intake measurement for this trait, only limited information is currently available. This data will continue to increase through the AWA PTP. Based on the 2,000 records currently evaluated, significant trait correlations have already been determined and these are used in the genetic evaluation to produce NFI WBVs. Animals linked to performance data will have higher accuracy WBVs.
Practical Use in Wagyu Breeding Programs
For breeders, the NFI WBV enables:
- Selection of sires that transmit superior feed efficiency
- Improved economic efficiency in commercial progeny
- Differentiation of genetics beyond growth and carcase performance alone
For commercial Wagyu production:
- Lower NFI genetics rare expected to reduce feed costs per kilogram of carcase
- Potential reductions in environmental footprint through lower feed demand
These benefits compound over long feeding periods typical of Wagyu systems.
Why the NFI WBV Is Being Introduced Now
The NFI WBV is being introduced now because:
- Sufficient Wagyu-specific feed intake data has been accumulated
- Genomic connectivity allows reliable population-wide prediction
- AWA now operates an independent genetic evaluation pipeline
Conclusion
The introduction of the Net Feed Intake WBV provides Wagyu breeders with a new tool to improve profitability and sustainability, by identifying animals that require less feed for the same level of performance. As net feed intake data records continue to increase, NFI WBVs and accuracies will reflect the data submitted by members, including through the AWA PTP.