The Holstein Association USA has announced a a new Total Performance Index (TPI) formula to help recognize the needs, strengths and opportunities in the Holstein breed. The new formula has slight modifications from its last updated in May 2007. TPI is used to rank Holstein cattle and assist dairy producers worldwide in identifying superior cattle with a combination of high production, sound conformation and desirable health and fertility.
“The Genetic Advancement Committee recommended the update to the TPI formula to reflect the wants and needs of today’s dairymen,” said Dr. Tom Lawlor, Holstein Association USA Director of Research and Development. “The opportunity to improve the lower heritability health and fertility traits is greater now than ever before with the information provided by genomic evaluations.”
The updated TPI formula includes an increased emphasis on Productive Life (PL) and Daughter Pregnancy Rate (DPR); maintains the current emphasis on udders and feet and legs; aims to slow the increase in body size; and slightly reduces the emphasis on production. New weights for the major categories include: 42 percent on production (down from 45 percent), 33 percent on health and fertility (up from 27 percent), and 25 percent on conformation (down from 28 percent).
This change comes along with the updating of the genetic base, which occurs every five years, to ensure the genetic evaluations are being compared to a current and up-to-date population. The new base now reflects cows born in 2005, whereby the average PTA of those cows equals zero. Some adjustments to the major traits include:
Milk – 415
Fat – 15
Protein – 14
PTAT – 0.87
UDC – 0.85
FLC – 0.65
Source: Holstein Association USA