NRC Overview – Protein & Amino Acids – Dr. Mark Hanigan, Dr. Jeff Firkins, and Dr. Hélène Lapierre

Posted: Oktober 19, 2021


Dr. Mark Hanigan, Virginia Tech

Dr. Jeff Firkins, The Ohio State

Dr. Hélène Lapierre, Agriculture and Agri-Food Canada

Episode: 27 NRC Overview – Protein & Amino Acids

Podcast Topic

We 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.


Our Dairy NRC series of Real Science webinars was very well received and tonight we are talking about the chapter on protein and amino acids. Dr. Mark Hanigan discussed the sections his team worked on in the new NRC. First thing was updating the feed library. After the feed library was updated they identified other updates like the microbial equations and RUP equations, adjustability data for the RUP and for microbes as well as the composition of the microbes. (6:49)

Dr. Jeff Firkens discussed the difference with the amino acid profile by accounting for protozoa flow which is important for lysine, because protozoa have a lot more lysine than bacteria. So they are attributing microbial protein sources as better sources of lysine. (22:02)

Dr. Hélène Lapierre discussed their updates to metabolic fecal output and urinary endogenous output since the previous data dated back to 1977. The updated data showed a large change. Endogenous urine output was twice as much as it was previously, and fecal output was much lower than it was previously. (36:36)

Dr. Mark Hanigan discussed the new milk protein yield equation and used the analogy of an assembly line. Each nutrient is a separate contributor to the assembly line and without a certain nutrient that assembly line will slow down. Once a little more of that nutrient is provided the assembly line speeds back up. (47:33)

Dr. Hélène Lapierre discussed efficiency and working with cows of the past, and their published data, to provide the specifications for cows of the future that are producing more. So the scaling factor should be based on current herd averages. (58:33)

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 and click on the NRC series for a link and the discount code.

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This podcast is sponsored by Balchem Animal Nutrition and Health.