Protein is expensive to produce, so it stands to reason that it would receive a negative weight in milk markets where it had no value. Cheese Merit is for producers who ship to cheese plants. Protein premiums are high in such milk markets. Milk volume gets negative weight in the Cheese Merit index, while protein receives the highest emphasis of any of the three merit equations. USDA uses Net Merit to determine where active AI bulls rank compared to the active AI bulls from the previous genetic evaluation.
Interpretation is straightforward.
The previous list is used so that rank percentiles can be calculated along with the proofs and Merit indexes. Rank Percentile is the single most important number published in a bull's genetic evaluation. It is important because Net Merit is used to determine the ranking, and Net Merit includes the most important traits for commercial milk production, properly weighted for economic value in a manufacturing milk market. Secondly, Rank Percentile is important because it considers the genetic merit of alternative bulls that might be used in place of any given active AI sire. Generally, if a bull's genetic merit were below the 70th percentile, a producer would probably be better off using young sires in AI with the best pedigrees.