NUTBAL's primary purpose is to provide the livestock industry the means to monitor the nutrient concentration in the animal's diet and determine if the current diet is sufficient to meet performance goals set by the producer. NUTBAL is a decision support system which models crude protein and net energy status of cattle, sheep and goats.  This computerized decision aide lets the user their herd, environmental conditions, and establish weight performance targets. This information is then coupled with NIRS fecal analysis results from the Grazingland Animal Nutrition Lab, (GAN Lab), to produce an animal performance report and a least cost nutrition management plan .

Nutbal Reports include the following information:

  • plan of nutrition
  • weight gain or loss
  • the nutrient most limiting animal performance
  • least cost feeding solution
  • amount of feed and forage consumed

Unlike most feeding systems which are applicable only to housed animals, NUTBAL calculates what animals will consume ad libitum under grazing conditions.  In most cases, voluntary intake of ruminants in free-ranging conditions exceeds that predicted by NRC or ARC intake equations.


As part of the NIRS/NUTBAL system, NUTBAL is an effective nutritional monitoring tool designed for ranchers and other free-grazing managers.  The system generates valuable information that enables the user to make informed and timely decisions regarding animal nutrition and grazing management. 

Private enterprise applications of the NIRS/NUTBAL system are varied and can be custom designed to meet the goals of the individual user.  Most private users employ NUTBAL to assist in one or a combination of the following:

  • Monitoring a reproductive herd's nutrition year round
  • Winter feed management
  • Nutrition monitoring of grazing stockers
  • Developing and managing replacement breeding stock
  • Developing rotational grazing protocols

Corresponding goals of NUTBAL user may include but are not limited to:

  • Improving body condition more economically
  • Managing weight loss during drought or dormant forage periods
  • Maintaining desired body condition during critical periods to enhance productivity
  • Enhance effectiveness of supplement feeding by indentifying when forage is inadequate, when forage quality recovers and how much feed is needed to meet goals
  • Meeting weight gain goals

Various agencies and groups also use the NIRS/NUTBAL system as a research tool in developing guidelines for the public, collecting data, and facilitating environmental conservation, to name a few.  Such programs include EQIP, CSP, and the Forage Quality & Animal Well-being Program.


Access to NUTBAL is available via the interactive website, NUTBAL Online.  The online application allows users to submit their information for NIRS analysis on a livestock fecal sample which is then mailed to the GAN Lab.  Once the GAN Lab completes and records the sample's NIR analysis, the interactive website automatically generates NUTBAL reports for the sample based on data entered by a user. The NUTBAL software is available in a metric unit of measure version as well as the English unit version.

Model Systems

The NUTBAL model uses a combination of published systems including the NRC's 1984, 1987, 1996 basic nutrient requirements formulas, Fox et al. (1988) adjustments to the NRC equations, McCullum's rumen degradable protein thresholds and DOM/CP ratio concepts and Moore and Kunkel's concept of intake change rate and deviation of metabolizable energy due to associative effects in growing animals.  Where NUTBAL deviates from other systems is in the application of a quasi-metabolic fill system to predict dry matter intake of the animal. This approach allows modeling of fecal output processes, which consider more than just the digestion process. Other factors are derived from literature review, expert opinion and unpublished data extrapolated from prior studies.  Impacts of forage availability, appetite drive and associative effects can be characterized in both fecal output as proportion of fat-corrected body weight and metabolizability of ingested forage.

CNRIT Projects

NUTBAL and the NIRS/NUTBAL monitoring system are an important part of several CNRIT projects that include Afghanistan PEACE, East Africa LEWS, FRAMS, Mali Livestock and Pastoralist Initiative, and Mongolia LEWS. While US based projects tend to focus towards conservation or efficiency issues, international projects benefit from the ability to evaluate and project changes in animal well-being which can be closely followed by changes in the people's well-being in a region.