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Base change and update TPI formula
Base change and TPI formula update
During the index run in the USA at the beginning of April, the five-year base change will be implemented again. Most breeding values have increased since the last base adjustment in 2015, for which cows born in 2010 are the basis. The introduction of genomics in 2008 and the shortening of the generation interval has resulted in an additional increase in genetic progress. By updating the base now (new base is born cows in 2015), most breeding values of individual traits will decrease considerably.
In the upcoming index run, that will mean a reduction of about 500 pounds for milk production and Fat and Protein will drop on average 24 and 18 pounds. For type, the adjustment will be approximately -0.75 PTAT, -0.85 UDC and -0.50 F&L. And for the health traits -1.8 PL, -0.24 DPR and +0.08 SCS. Breeding values for calving ease will also increase on average by +0.4 (SCE) and +1.9 (DCE). By adjusting the constant in the TPI formula, the TPIs will remain in general on average.
For more information on the April 2020 USA base change, CLICK HERE.
The weighting of several traits in the TPI formula will also be updated in April:
1. The Fat: Protein ratio is now equal (both 19% in the TPI formula).
2. Health traits (such as milk fever, displaced abomasum, ketosis, mastitis, metritis and retained placenta are now also weighed (2%).
3. Leg set side view becomes an optimum trait and weighed in F&L and therefore also in the TPI.
4. Age at 1st calving is now included in the Fertility Index.
5. Productive Life weighting is increased from 4 to 5% (taken from Dairy Form).
As a result, the weighting in the TPI formula is now: Production 46%, Health and fertility 28% and Type 26%.
For more information about the April 2020 USA TPI formula, CLICK HERE.
