CDCB’s publications of 305-ME (mature equivalent) was discontinued and replaced by 305-AA (average age) as the standardized yield estimate for U.S. dairy cows. This change incorporates current knowledge about the key variables the impact milk yield and improves the accuracy of the estimate.
For the complete article, https://hoards.com/article-35331-moving-from-me-to-average-age.html
by Katie Schmitt for Hoard’s Dairyman Intel