- Professor and Range Specialist
- Texas A&M AgriLife Research & Extension Center at San Angelo
- (325) 657-7327
- Undergraduate Education
- B.S. Wildlife Science, Texas A&M University
- Graduate Education
- M.S. Range Science, Colorado State University
- Ph.D. Range Science, Texas A&M University
John Walker is a Professor and Resident Director of Research at the Texas A&M Agrilife Research & Extension Center in San Angelo, Texas. My responsibilities include providing leadership to a multi-disciplinary team of scientists that develop new technologies for increasing the efficiency and sustainability of range livestock and wildlife production. My research interest relates to developing new technologies for modifying diet selection of grazing ruminants. It has long been known that livestock grazing affects the botanical composition of vegetation communities. By avoiding some plant species and preferring others, livestock provide a competitive advantage to plants that are avoided, which allows them to increase and often dominate a site. Grazing systems were developed to help overcome this adverse effect of selective grazing on rangeland composition. I am interested in directly modifying the grazing habits of livestock through selective breeding, nutritional interventions and learning. In conjunction with this research, I have developed near-infrared spectroscopy (NIR) calibrations that use fecal spectra to predict the botanical composition of diets. I have also developed NIR calibrations to predict fleece yield and average fiber diameter from side samples. I do research and out reach on using Livestock Guardian Dogs as a predator friendly method of reducing depredation on sheep and goats. I am currently a Co-Pl on a USDA Sustainable Agricultural Systems project entitled “Enhancing Livestock Production from Rangelands in the Great Plains” that is using goats and prescribed fire to manage woody plant encroachment.
Research Interests and Specializations
Foraging ecology, grazing management
Walker, J.W., R. Pope, F. Pfeiffer. 2019. On tarm testing of FibreLux micron meter and OFDA2000 compared to Sirolan Laserscan.
Walker, J.W., W.C. Stewart, R. Pope, S.L. Spear, M. Ebert, T.W. Murphy. 2018. Evaluation of mean fiber diameter measurements by FibreLux micron meter and OFDA2000 in Texas and Intermountain west wool. Small Rumin. Res. 152:31-37.
Stewart, W. C., T. R. Whitney, E. J. Scholljegerdes, R. P. Adams, H. D. Naumann, N. M. Cherry, J. P. Muir, B. D. Lambert, J. W. Walker, K. D. Welch, D. R. Gardner, and R. E. Estell. 2015. Effects of Juniperus species and stage of maturity on nutritional, in vitro digestibility, and plant secondary compound characteristics. J. Anim. Sci. 93:4034−4047.
Walker, J.W., D.F. Waldron, E.S. Campbell, C.A. Taylor, Jr., C.J. Lupton, and S. Landau. 2013. Intermediate periodicities in juniper consumption and sampling strategies to estimate the diet of free-grazing goats. Rangeland Ecol. Manage. 66:209 – 215.
T.A. Glasser, T.A., S.Y. Landaua, E.D. Ungara, A. Perevolotskya, L. Dvasha, H. Mukladaa, D. Kababyab, J.W. Walker. 2012. Foraging selectivity of three goat breeds in a Mediterranean shrubland. Small Rumin. Res. 102: 7-12.