Description
The 7th revised edition of the Nutrient Requirements of Beef Cattle was released in 2000 by the National Research Council (NRC) through the National Academies Press. It represents an update to the Seventh Revised Edition originally published in 1996 and was developed by the NRC Subcommittee on Beef Cattle Nutrition, operating under the Committee on Animal Nutrition, Board on Agriculture and Natural Resources.
Like all NRC reports, it reflects a scientific consensus based on peer-reviewed literature available at the time and underwent a rigorous external review process. The publication provides science-based nutrient requirements for beef cattle across physiological states such as maintenance, growth, pregnancy, and lactation. It integrates energy, protein, mineral, vitamin, and water requirements with biological concepts such as feed intake regulation, body composition, and environmental stress. Importantly, the 2000 update supports the use of mechanistic prediction equations and computer-based models, moving beyond static requirement tables to allow nutritionists, researchers, and industry professionals to formulate diets, evaluate feeding strategies, and predict animal performance under a wide range of production conditions.
Since 1944, the NRC has published eight editions of the Nutrient Requirements of Beef Cattle, reflecting the progressive advancement of scientific knowledge in beef cattle nutrition. Each revision has built upon previous editions by incorporating new experimental evidence, improved conceptual understanding of nutrient utilization, and enhanced approaches to predicting animal requirements and performance.
The Eighth Revised Edition, released in 2016, represents the most recent comprehensive update of this series. It integrates contemporary advances in nutrition, physiology, and systems modeling, while also providing continuity with earlier editions. A historical perspective of these editions is presented here to highlight the evolution of nutritional concepts, methodological approaches, and decision-support tools that have shaped beef cattle nutrition research and practice over the past eight decades.
Simplified Revision History:
- In 1945, the National Research Council (NRC) released the “Recommended Nutrient Allowances for Beef Cattle” (NRC, 1945), in which the requirements for protein were based on the factorial concepts previously delineated by Mitchell (1929).
- The first revision of the beef NRC publication was released in 1950. In addition to the 1945 Beef NRC, the “Recommended Nutrient Allowances for Dairy Cattle” was also released in 1945.
- The beef NRC had the second revision released in 1958 (NRC, 1958).
- The third revision in 1963 (NRC, 1963).
- The fourth revision in 1970 (NRC, 1970). The NRC (1970) included a new section on “Nutrient needs of rumen microorganisms”.
- The fifth revision was released in 1976 (NRC, 1976).
- The sixth revision was released in 1984 (NRC, 1984). The NRC (1984) had major changes in the energy requirements section and included the concepts of ruminal protein degradation and bypass.
- The seventh revision of the beef NRC was released in 1996 (NRC, 1996) and updated in 2000 (NRC, 2000). These versions of the beef NRC included more complex and mechanistic nutritional models.
- The eighth revision of the beef NRC was released in 2016 by the National Academies of Sciences, Engineering, and Medicine.
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DOSBox 0.74-3 |
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The Beef NRC (1996, 2000) computer model, developed under the auspices of the NRC, represented a major step forward in translating the nutrient requirement equations of the Seventh Revised Edition into a practical, executable decision-support tool. The software was originally implemented for MS-DOS–based Intel x86 computers, using spreadsheet-driven logic compatible with platforms such as Lotus 1-2-3 and Quattro Pro, which were standard scientific computing environments at the time. This DOS-based implementation allowed users to operationalize NRC equations for energy, protein, minerals, and intake prediction in a structured and repeatable manner. However, as operating systems evolved beyond DOS—particularly with the advent of 32-bit and 64-bit versions of Microsoft Windows—the original NRC Beef Cattle software became increasingly difficult, and eventually impossible, to execute on modern systems without emulation. To preserve access to this historically important model and ensure its continued educational and archival use, a DOSBox-based workaround was developed. DOSBox emulates a complete x86 DOS environment, enabling legacy applications to run on contemporary Windows systems without modifying the original NRC code. Building on earlier DOSBox integrations (circa 2012), a modernized solution was completed in 2025, featuring a custom Windows batch launcher that automates environment validation, dynamically configures screen resolution, injects startup commands, and launches the NRC model seamlessly. The solution was fully packaged using Advanced Installer, resulting in a clean, professional installer with shortcuts, branding, and user-friendly deployment. Importantly, no changes were made to the original Beef NRC (1996, 2000) computational logic, ensuring that the scientific integrity and historical authenticity of the NRC model remain intact while extending its usability into the present computing era. |
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The current version of the 1996 Beef Cattle Nutrient Requirements Model is Loading...
Note that upgrading to this version may require uninstalling an earlier version.
Previous versions can be downloaded from here.
Changes to the Beef NRC (1996/2000) software are listed in this text file.
Registration
No registration is needed for the current version. Nonetheless, you are welcome to submit your comments to improve this model at the Contact us web page.
Developers
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SUBCOMMITTEE ON THE 1996/2000 BEEF CATILE NUTRITION: |
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Support
The following list summarizes corrections, enhancements, and functional improvements made to the software, presented in chronological order (newest to oldest). Each entry reflects updates implemented to improve stability, usability, and overall performance.
December 2025. A custom Windows BATCH launcher was developed to modernize the execution of the NRC Beef Cattle 2000 model under DOSBox 0.74-3. The script provides an interactive menu that allows users to select from multiple predefined screen resolutions, automatically updates the dosbox.conf file, and launches the model with the appropriate configuration. Additional enhancements include environment validation, error handling, branding, acknowledgments, and dynamic autoexec command injection for seamless startup of run nrc.ovr. Once complete, the entire application was packaged and distributed using Advanced Installer 23.3, enabling a clean, professional installer with proper shortcuts, file placement, and user-friendly deployment. No modifications or corrections were performed in the Beef NRC (1996, 2000) software.
December 2012. No modifications or corrections were performed in the Beef NRC (1996, 2000) software. The Beef NRC (1996, 2000) software was originally developed for Microsoft Disk Operating System (MS-DOS) or Personal Computer Disk Operating System (PC-DOS) of Intel x86 computers. Unfortunately, the software is incompatible with newer operating systems, such as Microsoft Windows XP, Windows Vista, Windows 7, and Windows 8, running on either 32-bit or 64-bit machines. DOSBox is a software tool that emulates a full x86 PC with sound and DOS capabilities. Most MS-DOS or PC-DOS (commonly referred to as "DOS") applications should run in DOSBox, but the emphasis has been on getting DOS games to run smoothly, which means that communication, networking, and printer support are still in early development (Source). DOSBox also has a DOS-like command prompt that is quite rudimentary and lacks many of the features found in MS-DOS (Source), but it is adequate for installing and running the Beef NRC (1996, 2000) model. DOSBox is licensed under GNU General Public License version 2.0 (GPLv2) and it can be downloaded from SourceForge. The revised Beef NRC (2012) software includes DOSBox 0.74 for PC x86 emulation, and it is installed automatically.
- ATTENTION: Usually, DOSBox detects when a mouse is available. When you click on the "DOS" screen the mouse should get locked (confined to the DOSBox window) and work properly. If the mouse does not work in the DOSBox environment, it will need to be locked manually by pressing CTRL-F10. The CTRL-F10 command will also unlock the mouse and return mouse control to the Windows environment.
Links
- National Animal Nutrition Program, National Research Support Project (NRSP-9) web site.
- 8th Revised Edition of the Nutrient Requirements of Beef Cattle web page.
- 7th Revised Edition of the Nutrient Requirements of Dairy Cattle web page.
- 8th Revised Edition of the Nutrient Requirements of Dairy Cattle web page.
- 2007 Nutrient Requirements of Small Ruminants web page.
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