Guests: Dr. Lou Armentano, University of Wisconsin-Madison and Dr. Mike Vandehaar, Michigan State University. Co-host: Dr. Glen Aines, BalchemWe are just coming off a very successful Real Science Lecture Series set of five webinars where we unveiled the new 2021 dairy NRC, a chapter at a time, and we can’t wait to have these sit-down conversations with each of our presenters and their guest.Dr. Lou Armentano summarizes the biggest changes from the 2001 edition to the 2021 edition within the energy chapter. He explained that their resource data shows that cows have changed, therefore the maintenance requirements for cows have changed. Since cows have biologically changed with genetic selection, they use more energy to maintain themselves. So that part of the chapter needed to be updated to reflect that change. (14:19)Dr. Lou Armentano discusses the reporting of fatty acid content in the feed. He expands upon fatty acid digestion, and how those fatty acids affect milk fat. (29:52)Dr. Mike Vandehaar discusses frame growth, which is the true structural growth of the animal, including muscle, bone, fat, gut tissues and gut fill as well as reserve depletion, which happens in all cows even when they hit maturity. The 2001 model wouldn’t change the equation solution when you entered structural growth as a factor. So they wanted to make sure that oversight was fixed in the new model. (37:33)Dr. Mike Vandehaar discusses feeding high starch diets versus high fiber by-products to cows through their lactation cycles. (45:47)Dr. Mike Vanehaar stresses that you can’t just trust the model you have to watch the cows and when you make a diet change try to figure out what the cows are telling you by observing and measuring things like milk production, milk compensation, intake, and body condition score. (1:04:04)Dr. Lou Armentano says that they have been playing with a functioning model for only about a month and a half so he encourages those who are going to use the new model to speak up if something seems to be a mistake so changes can be made to correct any issues. (1:04:40)As a reminder, we will continue breaking down the new 2021 8th Revised Edition of the Nutrient Requirements of Animals in podcasts releasing over the coming weeks. Be sure to subscribe so you don’t miss any of the new episodes. If you’d like to pre-order a copy and receive a 25% discount, visit Balchem.com/realscience and click on the NRC series for a link and the discount code. If you like what you heard, please remember to hit the 5-star rating on your way out.  Don’t forget to request your Real Science Exchange t-shirt. You just need to like or subscribe to the Real Science Exchange and send us a screenshot along with your address and size to ANH.marketing@balchem.com.Please subscribe and share with your industry friends to bring more people to join us around the Real Science Exchange virtual pub table.This podcast is sponsored by Balchem Animal Nutrition and Health.