What is JPI™?

JPI™: What is it? How is it used? What goes into it? These are all important questions when you look at the Genex Jersey lineup. First off, JPI stands for Jersey Production Index. JPI is a breed-specific selection tool. Updated in 2010, the current JPI formula has the largest emphasis on production traits – a 57% emphasis on those traits. Of that 57%, PTA Protein makes up 42% while the remaining emphasis (15%) is placed on PTA Fat. The remainder of the JPI formula is a combination of four fitness and longevity traits. At 15% is the Functional Trait Index (FTI). This index is designed to separate the impact of production and type traits on lifetime profitability. FTI is composed of a sum of the PTAs for the linear traits times their respective economic values. FTI is not published separately because it needs to be combined with production traits to be interpreted correctly. FTI was introduced in 1992, updated in 1998 and most recently updated in 2006. The FTI calculation has the highest weight on udder traits (54%), followed by body traits (41%) and finally foot angle (5%). Udder depth is the single largest contributor to FTI. Coming in at a 12% weighting, Productive Life makes up the next portion of the JPI formula. Productive Life is defined as “time in the milking herd before removal by voluntary culling, involuntary culling or death.” Rounding out fitness and longevity traits, Daughter Pregnancy Rate (DPR) is defined as the percentage of non-pregnant cows that become pregnant during each 21-day period. The DPR weight in the JPI formula is 10%. The final trait is Somatic Cell Score (SCS). SCS is an indicator trait for mastitis based on the direct measure of somatic cells in milk samples. JPI puts a 6% emphasis on SCS. The graph below is a great visual break-down of the JPI formula.

Reference: “2010 Jersey Performance Index™ (JPI).” American Jersey Cattle Association. www.usjersey.com/Programs/JPIIntro.pdf

------------------------------------------------------------------------------------------------------------

Author Leah James is our U.S. Jersey Marketing Manager.  James grew up on a family dairy farm and graduated from the University of Wisconsin-River Falls with a bachelor’s degree in agriculture education. She has since worked within the artificial insemination industry and for the American Jersey Cattle Association. Today, she and her husband also operate a 125-cow dairy consisting of registered Holsteins, Jerseys and Milking Shorthorns.