This metric is the change in the yield ratio over the past two weeks - i.e. did she increase or decrease in production relative to the herd over the past two weeks. As you would expect, positive numbers mean an improvement, and negative mean she is dropping.
1. Go to Herd Management -> Scratchpad.
2. Click Add or Remove Columns on the right side of the screen and then click on the small gold arrow next to Production.
Choose Yield 2wks
3. Click Apply.
Once you have made a new Yield Change Report you can save it under Herd Management or in Favourites where it will automatically update daily and be easy to refer back to at any time.