Contact Info

Blackland Research & Extension Center
720 E. Blackland Road
Temple, TX 76502-9622 
254-774-6150 fax
8am - 5pm Central, Weekdays

NIRS Technology

Scanning Sample

The GAN Lab serves livestock producers, managers, veterinarians, and ranch consultants.  The GAN Lab's research and services utilize near infrared reflectance spectroscopy (NIRS) to analyze animal fecal samples.  This technology allows the lab to return nutritional analyses within two days of receiving samples.  When combined with the Nutritional Balance Analyzer (NUTBAL), producers and managers have a reliable means of implementing a nutritional monitoring program that can enhance their decision making process.

The GAN lab provides livestock managers with rapid assessment of the nutritional value of diets of free-ranging livestock and tools to determine the animals’ nutritional well-being.  The GAN Lab has developed NIRS equations for analyzing animal fecal specimens to determine the quality of forage the animal(s) consumed.  The forage quality results include dietary crude protein (%CP), dietary digestible organic matter (%DOM), as well as fecal nitrogen (%FN) and fecal phosphorus (%FP).

NIRS graph

What is NIRS?

The NIRS process involves exposing a dried, ground fecal sample to light energy. The intensity of reflectance is measured across several hundred wavelengths in the near infrared band. Reflectance is influenced by number and type of chemical bonds in the feces. Primary wavelengths in prediction equations appear to be associated with the fiber, alkane and microbial fractions of the feces.

Research with NIRS

A major limitation to application of an advanced nutritional management model is the inability to predict the level of degradation of crude protein in the rumen and lower gut of free-ranging animals. Several scientists at Texas A&M University began researching NIRS technology in the early 1990's and were successful at predicting dietary cude protein and digestible organic matter (DOM) of cattle (Lyons and Stuth 1993) and later with small ruminant Spanish goats (Leite and Stuth 1995) via fecal profiling. This research was conducted in collaboration with experiment stations at various sites in the mid-South Texas, Central Texas, Central Oklahoma, and Central Missouri.  Laboratory values were regressed against matched fecal spectra using a Perstorp Scientific 6500 machine equipped with ISI software. Known diet samples were matched with feces of intact cows grazing a wide variety of forages. These diet - fecal pairs were used to develop a reference data set to build prediction or calibration equations. Fecal equation diet quality predictions were then validated against herds with known diet qualities. Equations developed to date appear to be highly reliable across a broad spectrum of forage types. Currently, the lab can predict dietary crude protein (CP%) and digestible organic matter (DOM%) as well as fecal nitrogen (FN%) and fecal phosphorus (FP%). Dietary content of dicots can be estimated for regions of contrasting C3 dicot species (forbs and browse) and C4 warm-season grasses.

Field Unit 1

Linking NIRS with Computers

Since the initial NIRS studies concluded, over 30 research projects have been conducted using NIRS technology to analyze diet quality of cattle, deer, elk, bison, and pandas among others.   In 1995, the orginal NUTBAL application was created to provide a means for determining the least cost nutritional management plan using the research from NIRS fecal profiling.  The application has been built upon with further research and is now an online "cloud computing" application designed to provide site specific nutrition recommendations.

The NIRS results provide forage quality data needed by the decision support system, NUTBAL Online.  This tool uses the animal description (the kind, class and breed), body condition, forage conditions, supplemental feed information, environmental conditions, performance targets and NIRS results to produce a nutritional balance report for protein and net energy and a report for least-cost feeding solutions.  If a deficiency exists, NUTBAL can determine the amount of least-cost feedstuff needed to correct the problem.  Such reports can be used by directly by the producer or the GAN Lab staff, trained consultants or extension personnel to provide advisory reports to clients.  Customers of the GAN Lab may also request a NUTBAL Advisory in addition to the NIRS/NUTBAL System Report.  This Advisory is an interpretation of the results and recommendations for nutritional management.


  • Lyons, R.K. and J.W. Stuth. 1992. Fecal NIRS equations for predicting diet quality of free-ranging cattle. J. Range Manage. 45:238-244.

  • Leite, E.R., and J.W. Stuth. 1995. Fecal NIRS equations to assess diet quality of free-ranging goats. Small Ruminant Research. 15:223-230.

  • Stuth J.W., and R.K. Lyons. 1995. NIRS-NUTBAL Nutritional management system for cattle. In: Ellen R. Jordan (ed.) Proceedings of Mid-South Ruminant Nutrition Conference.