Brad Barham All West/Select Sires Sales Support Manager
The new April proofs being released will look a little different, so here’s a “head’s up” on what you can expect! The AJCA has made changes to the JPI formula effective April 2017. This new formula is called JPI 2017 and is aimed at maintaining the fundamentals of Jersey sustainability in the market today. In the 2012 study published by Caper and Cady, they concluded that Jerseys need to do three things to be sustainable:
- Increase production
- Maintain body size
- Maintain OR improve their components
AJCA’s new formula aims to increase production, improve the component density in milk, and moderate body weight all while improving herd life, fertility, udder health, and functional conformation. You will see newly added traits PTA milk (also called CFP milk), body weight composite (similar to Holstein’s composite), and PTA Livability. In the chart below you will see a 13% decrease in protein emphasis in this formula, but don’t let that fool you too much as CFP or PTA Milk is added back in at 8%. So the high protein sires will still hold rank quite well, for the most part. You will also notice a 4% decrease in Productive Life, however that 4% was moved to Livability. This was established by following the ratio of PL to Livability in the Merit traits. For a further explanation, please see the link at the bottom of this page.
Visually, the JPI numbers will re-scale causing an appearance of a “base-change.” However, all the numbers that make up JPI will not move like in a normal base-change year. Because of the dropped weighting in protein pounds alone, we will see some bulls re-scale by up to 35-40% on JPI while others will re-scale by 15-25%. Rankings on the upper end will seem quite similar to what you see on December proof data. Bulls with higher CM$ and pounds of fat do see a slight advantage in this re-scaling scenario, as the differential between pounds of protein and pounds of fat has now decreased. This new formula is actually highly correlated to the current CM$ ranks.
For an excellent explanation of the new JPI please watch this YOUTUBE video produced by Cari Wolfe of the American Jersey Cattle Association.
For more info on Body Weight Composite (BWC) please click HERE