Creating a well-balanced and properly mixed feed ration is essential to dairy cow productivity and health. The dairy's feeding manager should have two objectives: 1) to have the nutrient composition of the ration consumed by the cows the same as the one for the nutritionist’s ration on paper, and 2) for the nutrient profile of the freshly delivered feed to be the same as the one in the leftovers the next morning. Along with the ingredients loaded in the mixture, the particle size distribution plays an important role in determining the ration the cow actually consumes and digests. It is important to evaluate the total mixed ration (TMR) to determine whether there is an opportunity to improve at any step in the process of making the feed, including the forage harvest, ingredient loading and mixing, and feed delivery. Useful, on-farm tools like the Penn State Particle Separator (PSPS) have proven to be key in monitoring TMRs on a variety of levels. Recording PSPS results along with lab nutrient analysis results over time will create a history of what is being fed out and consumed by the cattle and allow for monitoring of trends and identifying potential issues.