Publish date: 27.02.25
Genetics are continuously improving, and dairy producers are making faster genetic progress than ever before because of targeted genetic selection. Therefore, to guarantee their accuracy and relevance, genetic evaluations must evolve. Additionally, they need to adapt to incorporate the most recent research, new data, and breeding advancements introduced to the dairy industry.
Because of this, you should be informed of the U.K. annual base change happening in April 2025. After reading this blog, you will understand what a base change is, why it happens, and what its effects are.
What is a Base Change?
We can learn how an animal’s genetic worth stacks up against the average milking at the time by using genetic indexes. For all traits, the PTA (Predicted Transmitting Ability) of this average “base” animal is zero. However, as the national herd advances genetically, this average base improves genetically each year. It is for this reason that we have base changes. In other words, think of a base change as a report card of how much genetic progress has been made when compared to the previous generation.
The genetic base for all breeds in the U.K. resets each April to the average genetic merit of cows born over a four-year window to mimic the breed average. A base change ensures that genetic evaluations remain meaningful and continue to provide an accurate representation of today’s genetic landscape. The trait change estimates will be provided closer to April 2025 by the AHDB.
The benefit of a yearly base change is that you always have an updated relevant base. However, over time, you might not feel, see, or appreciate the genetic progress being made as the result of an annual update.
What Changes Can You Expect to See?
You might be questioning what changes you might see, which is valid. When comparing this genetic evaluation to the previous, the base change may result in lower figures for several traits. However, this does not imply that a particular bull or female has lost its genetic worth overnight. Rather, it merely indicates that the population as a whole has improved and that the baseline has been adjusted to reflect recent genetic progress. Your herd will continue to benefit from the same high-quality sires you have depended on before.
A base change reflects the improvement in genetic progress of the overall population and resets the baseline to align with it.
It will also be important to note that CDCB will also be updating Net Merit $ (NM$) in April 2025. NM$ ranks dairy animals on their combined genetic merit for nearly 40 economically important traits. NM$ will drop around 450 points and will be three digits once again and start with six, seven, or eight. There were no new traits added this time, but there were several updates to traits already included. The new formulation includes the following changes:
- Increase weight on Milk and Fat
- Decrease in Protein
- More emphasis on lower cow weight, impacting Body Weight Composite
- Less total weight on Fertility traits like Daughter Pregnancy Rate
- Increased emphasis on Cow Conception Rate
If you utilise this index, please be aware of this change.
Interpreting the U.K. Base Change
With a base change, it will be important for dairy producers using criteria to update their thresholds. Why? With the changes in some traits, no adjustments could lead to zero bulls or a limited number of bulls meeting your criteria. We suggest that when adjusting your criteria, align your thresholds with the base change. This means if the base change is down 50 kilograms for Milk, then your new Milk criteria should be reviewed to make sure it is still appropriate. Criteria changes should still allow for the inclusion of the same number of bulls as before the base change.
It’s critical for dairy producers to appropriately understand these changes to make more informed breeding decisions. Here’s what you need to remember about the upcoming base change:
- The genetic value of the individual bulls and cows has not changed; only their rankings in relation to a new population have been adjusted.
- A base change highlights the remarkable advancements made in breeding programs over time.
- Your genetic selection decisions should remain focused on your milk market, facility, management system, and operational goals; the underlying genetic potential of animals remains the same.
The main point of this discussion is that neither genetics nor the animals themselves have changed. Following a base change, only our perception of an animal’s genetic superiority has changed.
While the next genetic base will look different, we should celebrate the sheer amount of genetic progress that has been made! Genus ABS is pleased to contribute to advancing the industry through genetic progress. We have been privileged to help our customers make significant genetic progress over the last 80 years, and we look forward to continuing to do so in the future.
To learn more about the U.K. base change, contact your Genus ABS Genetics Advisor.
01270 616681