Brattleboro, Vt. - Following a recent vote by the Holstein Association USA, Inc. board of directors, a new Total Performance Index (TPI) will be implemented with the April 2011 national genetic evaluations. Discussions regarding the TPI formula were re-opened following a resolution brought forth at the 2010 Holstein Association USA Annual Meeting in Bloomington, Minn. The resolution, submitted by the Wisconsin Holstein Association and affirmed by the delegates, asked the board of directors to "re-evaluate the TPI formula and raise the type contribution to a level that more accurately reflects what breeders desire for a balance of type and production." The TPI formula was last amended in January 2010.
In summary, the April 2011 TPI formula removes 5 percent weighting from Productive Life (PL), and adds a 1 percent emphasis to PTA Protein (PTAP), 2 percent to Udder Composite (UDC), 1 percent to Feet and Leg Composite (FLC) and 1 percent to Daughter Pregnancy Rate (DPR). The complete formula appears as the first image to the right.
Major Weightings of the April 2011 TPI Formula
When looking at the weight of major categories in the formula, the emphasis has shifted slightly:
Production 43% (+1% from January 2010 TPI formula)
Health & Fertility 29% (-4%)
Conformation 28% (+3%)
Analysis of the Formula Changes on Top 100 TPI Bull Averages
The table below compares the averages of the top 100 TPI bulls (having at least 85 percent reliability to qualify for the Top 100 list), comparing the new April 2011 TPI formula, the previous TPI formula (January 2010), and also the Net Merit (NM$) formula. As the table illustrates, the April 2011 formula results in higher averages for all type traits, addressing the issues raised by the delegate resolution. It also shows slight increases in the averages of all production traits. The new TPI formula places significantly more emphasis on type traits than the Net Merit $ formula, results in a higher average for PTA Milk, comparable averages for pounds of fat and protein, and slightly lower averages for the health traits.
More Rescaling Also Coming in April from USDA
The other change that will happen in April 2011 is that non-genomic cows will be put on a "level playing field" with animals that do have genomic evaluations, by having their genetic values rescaled by USDA. This process was done to animals with genomic evaluations in April 2010. Holstein Association USA will provide more information for the membership as it becomes available from USDA in the coming weeks.
For the most up-to-date information about how changes will impact Holstein breeders, visit www.holsteinusa.com.
Source: Holstein Association USA, Inc.