The Ranch Diagnostics Lab is a service laboratory offering decision support for better nutritional management of livestock and stewardship of natural resources. The lab offers Fecal Near-Infrared Spectroscopy (FNIRS) analysis of livestock and wildlife samples to estimate diet crude protein, diet digestible organic matter, which is approximately equal to total digestible nutrients (TDN), as well as fecal nitrogen and phosphorus. These values can be combined with animal information such breed, age, class, weight, body condition score (BCS), and weather conditions, into the Nutbal software to predict animal performance (i.e. weight change) and thus inform management decision making.

Improving technology for healthier livestock and land resource management

History of the Ranch Diagnostics Lab

In 1987, the Ranching System Group at Texas A&M University first began its work on the technologies now used by the Ranch Diagnostics Lab. Originally a research-based operation to study animal nutrition and grazing behavior, our focus centered on developing a system to monitor range conditions by utilizing fecal profiling via near-infrared reflectance spectroscopy, NIRS, analysis. The system was developed to estimate the quality of the diet consumed by grazing animals using fecal samples rather than relying solely on manually collected forage samples. This greatly reduces the cost of field sampling and improves the accuracy of diet quality predictions. Fecal samples are collected and scanned using NIRS instruments to capture their near-infrared spectra. Our calibration equations, developed through many years of research, are then applied to the fecal sample’s spectra to generate dietary crude protein (%CP), digestible organic matter (%DOM), fecal phosphorus (%FP), and fecal nitrogen (%FN) results. These results, in essence, put a “feed tag” on the pasture the animal is grazing. For more information regarding equation development, visit our NIRS Technology page.

While the intent was to develop a non-invasive tool for range research, its potential benefits to the private sector soon became evident during ranch trials conducted in the early 1990s. The first cattle equations were developed, tested and published in 1992 by Drs. Jerry Stuth and Robert Lyons. The success of the first equations led to the opening of the Grazingland Animal Nutrition Lab, GAN Lab, to offer services to livestock managers nationwide. After completing the cattle equations, our research turned to developing diet quality equations for goats, white-tailed deer, sheep, elk and equines.

Expanding nutritional decision-support tools

To further utilize the NIRS results, we developed a nutritional balance profile, NUTBAL, software program first released in disk operating system, DOS, in 1995. In 1999, the Windows version of NUTBAL Pro was released, integrating fecal NIRS results with animal, pasture, environmental, and management information to generate nutritional balance and animal performance reports. NUTBAL later evolved into NUTBAL Online, a web-based platform that incorporates many updates and improvements since the first release. NUTBAL’s primary purpose is to provide the livestock industry with the ability to monitor nutrient content in the animal’s diet and determine if the current diet is sufficient to meet performance goals set by the producer. This decision support software generates reports describing animal performance and cost-effective feed solutions. These two technologies came together to form the NIRS/NUTBAL system, which has been used in the U.S. and abroad for decades.

Since 1999, we have expanded the use of NIRS technology for fecal profiling by establishing new labs in East Africa, South America, Mongolia, and Afghanistan through World Bank and USAID grants. Research applications also expanded beyond fecal profiling to include areas such as soil carbon analysis.

As the use of these technologies expanded, the GAN Lab continued the development and application of fecal NIRS and nutritional decision-support tools while providing analytical services to livestock producers, wildlife managers, agencies, Extension professionals, and researchers across the United States and beyond.

Following Dr. Stuth, the lab was led by Dr. Jay Angerer, Dr. Raghavan Srinivasan, and later Dr. Doug Tolleson. Dr. Tolleson played an important role in continuing the work of the GAN Lab, building on the foundation established by earlier researchers while advancing its research and service mission and helping carry its longstanding legacy into its next chapter.

From GAN Lab to Ranch Diagnostics Lab

In 2026, the GAN Lab transitioned to the Ranch Diagnostics Lab under the Center for Grazinglands and Ranch Management, CGRM. The new name reflects both the lab’s history and its expanding role in supporting ranchers, researchers, and natural resource professionals.

As part of CGRM, under the leadership of Dr. Jeff Goodwin, the Ranch Diagnostics Lab continues the fecal NIRS and nutritional diagnostic services developed through decades of research while expanding its capabilities and collaborations to support livestock and wildlife management, water quality assessment, soil health management, and broader whole-ranch decision-making.

From its beginning as a research effort in 1987, through decades as the GAN Lab, to its evolution into the Ranch Diagnostics Lab, the mission has remained consistent: to translate applied science into practical information that supports informed decision-making for grazing animals and the landscapes that sustain them.