With April 2020 genetic evaluations comes a newly updated TPI formula. While the changes are not major, it is important for you to stay aware of these updates, especially if TPI is your genetic plan of choice.
WHAT ARE THE KEY TPI UPDATES?
1. The fat to protein ratio is now equal
Previously, pounds of protein was weighted at 21% of the total index, while pounds of fat was weighted at 17%. Due to market conditions, these weights are now equal, at 19% each.
2. The CDCB health traits are now included in TPI
Within the health trait category of TPI, you’ll now see that the six CDCB health traits (resistance to mastitis, ketosis, retained placenta, metritis, displaced abomasum, and milk fever) are included. The Holstein Association has combined the six traits together into one economic index, which carries 2% of the total weight of the TPI formula.
This 2% weight essentially comes by removing 1% weight from Somatic Cell Score and 1% weight from Daughter Calving Ease. This makes sense, since the six health traits account both for resistance to mastitis, and other metabolic diseases that typically occur around calving.
3. Foot & Leg Composite (FLC) now includes emphasis on Rear Legs Side View
The Holstein breed has been trending toward a more posty, or straight, set to the rear legs. To help correct this two-way trait, Rear Legs Side View will now be included as part of the foot & leg composite index.
4. There will be 1% less weight on conformation, and 1% more weight on health
Because creating healthy, trouble-free cows is a goal that all producers share, Holstein USA has decided to move 1% weight away from Dairy Form in the conformation category of TPI, and shift that weight to Productive Life, within the Health category. With that shift, the new category weights of TPI are shown here.
Additional updates that the Holstein Association USA is making to the TPI formula are as follows:
- The fertility index now includes the trait Early First Calving
- The standard deviations for traits are updated