Dr. John Walker, Professor and Resident Director of Research

Texas A&M AgriLife Research and Extension CenterJohn Walker
7887 U.S. Highway 87 North
San Angelo, TX  76901

Phone: 325-657-7327
Fax: 325-658-4364
email: jwalker@ag.tamu.edu

Academic Affiliation: Ecosystem Science and Management,
Texas A&M University

Phyllis Benge
Senior Administrative Coordinator II

RESEARCH FOCUS:

I am 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 six 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 calibrations that use fecal spectra to predict the botanical composition of diets.

 

CURRENT PROJECTS:

  • Development of fecal near-infrared reflectance spectroscopy calibrations to predict botanical composition of diets
  • Improving the use of goats to control juniper in the Edward’s Plateau of Texas
  • Targeted grazing by sheep and goats to manage vegetation
  • Use of game cameras to estimate population parameters of white-tailed deer

 


RESUME

EDUCATION:

Ph.D. (1988)  ·  Range Science, Texas A&M University
MS (1981)  ·  Range Science, Colorado State University
B.S. (1976)  ·  Wildlife Science, Texas A&M University; graduated Cum Laude


PROFESSIONAL EXPERIENCE:

1997 – present
Professor and Resident Director of Research  ·  Texas A&M AgriLife Research and Extension Center – San Angelo, TX
Responsibilities include providing leadership to a multi-disciplinary team of six scientists that develop new technologies for increasing the efficiency and sustainability of range livestock and wildlife production. Oversee facility maintenance and improvements including approximately 20,000 acres of rangeland located on six properties in four counties. Develop and administer local policies for regional research and extension facility. Provide leadership both nationally and locally for the development of targeted livestock grazing for landscape enhancement and the use of animal genetics to modify livestock dietary preference. Develop near-infrared spectroscopy solutions in support of research in foraging ecology and animal nutrition. Adjunct Professor Animal Science – Angelo State University.

1988 – 1997
Rangeland Scientist (GM-13)  ·  USDA-ARS Sheep Experiment Station – Dubois, ID
Designed and conducted research to improve sustainable utilization of rangelands.  Studies included: combination grazing of sheep and cattle; use of grazing livestock to control noxious weeds; genotypic and phenotypic factors affecting foraging behavior; development of first fecal near-infrared spectroscopy calibrations for predicting botanical composition of ruminant diets, weed ecology; low input sustainable sheep production systems; importance of rangelands in global carbon budgets; and development of new techniques to monitor rangeland health.  Developed facilities necessary to accomplish research objectives in this new research area at the Sheep Station.  Supervised post-doc, secretary, 2 technicians and several summer interns. Served as acting research leader at U.S. Sheep Experiment Station for 1 year where I provided leadership for this 78,000 acre facility and 40 employees. Adjunct faculty appointment at University of Idaho, Utah State and Washington State Universities.

1985 – 1988
Graduate Research Assistant  ·  Department of Range Science, Texas A&M University – College Station, TX
Conducted research on the effect of different grazing systems on cattle behavior, nutrition, and forage production.  Managed Range Science Department registered Brangus research herd and 1,000 acre Rangeland Research Area.

1980 – 1985
Research Associate  ·  Texas Agricultural Experiment Station – Seymour, TX
Supervised and coordinated ranching and research at the Texas Experimental Ranch a joint venture between the Texas Agricultural Experiment Station, area ranchers, and businessmen formed to study methods for increasing the effic­iency of beef production in the Texas Rolling Plains.

1978 – 1980
Research Associate  ·  Department of Range Science, Colorado State University – Fort Collins, CO
Coordinated research activities, managed budget, collected, and analyzed data, and prepared reports for a National Science Foundation interdisciplinary research project on beef production from forage or grain feeding systems.


RESEARCH ACCOMPLISHMENTS:

The primary focus of my research has been the understanding and management of diet selection by grazing livestock as a way to affect the consequences of domestic herbivory on rangeland ecosystems. In pursuit of this I have investigated the effect of grazing systems on many aspects of range livestock production systems, the use of livestock to manage noxious weeds, and the use of selective breeding to modify diet preference. I have also investigated a variety of other topics including rangeland monitoring, many aspects of range livestock production system, brush removal to increase rangeland water yield, and fecal NIRS to predict diet composition.


COMPETITIVE GRANTS:

2012  (20,000) NSIIC Wool Research and Outreach Montana State University Texas A&M University
2011  (70,000) TDA Instrumentation for Objectively Measuring Animal Fibers
2011  (20,000) TDA Natural Fibers Research Grants Comparison of Texas Rambouillet Sheep and Australian Merino F1 Crosses
2008  ($35,000) USDA-APHIS-VS Scrapie Surveillance
2007  ($83,000) General Atomics – Strategic Fuel Supply: Develop Rapid Analytical Techniques to Determine Nutrient/Oil Content of Algae
2006  ($200,000) NRCS-GLCI – Bio-Control of Invasive Plants Using Sheep and Goats C0_PI with American Sheep Industry Association
2005  ($46,243) National Sheep Industry Improvement Center – Prescribed Grazing for Vegetation Management: A Handbook for Sheep and Goat Producers and Land Managers
2005  ($74,000) Joe Skeen Institute for Rangeland Restoration
2004  ($165,000) The United States Israel Binational Agricultural Research and Development Fund – Goats for Maximal Efficiency of Brush Control
2001  ($128,000) Texas Food and Fiber Commission – Improving the Use Of Goats to Manage Juniper Co-PI
1997  ($300,000) Upper Colorado River Authority North Concho River Waershed Brush Control Planning, Assessment & Feasibility Study
1995   ($96,636) National Research Initiative Influence of Riparian Herbage on Water Quality of Rangeland Streams Co-PI
1991  ($78,130) CSREES Use of domestic Livestock for the Biological Control of Leafy Spurge
1991  ($40,000) USDA-ARS Competitive Post Doctoral Research Associate
1990  ($15,000) EPA, Agriculture in concert with the Environment, Control of Leafy Spurge by Grazing Goats
1989  ($2,000) USDA-ARS Minority High-school internship


PUBLICATIONS:

60 – Journal
1 – Book editor
5 – Book Chapters
55 – Other
37 – Abstracts


AWARDS:

Publication Award Technical Writing Texas Section SRM 2008
Outstanding Achievement Award Society for Range Management 2007
Certificate of Appreciation for serving as acting research leader 1996
Certificate of Merit USDA Agricultural Research Service 1994
Nominated for Upper Snake River Federal Employee of the Year 1992
Certificate of Appreciation USDA Agriculture Research Service 1992
Tom Slick Fellow Texas A&M University 1987‑1988


PROFESSIONAL ORGANIZATIONS:

American Sheep Industry Association
Society for Range Management
Council for Agricultural Science and Technology
World Future Society
Gamma Sigma Delta Honor Society for Agriculture


PROFESSIONAL ACTIVITIES:

Second Vice President Texas Section Society for Range Management 2012
Member SRM Nomination committee 2011 –
Program Chair TX Section SRM Annual Meeting 2011
Chair & Organizer SRM Targeted Grazing Committee 2009 – 2011
Chair Texas Sheep and Goat Raisers’ Association – Animal Health and Product Development Committee
Council of Resident Directors Chair, 2006
Texas A&M University Institutional Animal Care and Use Committee, 2001 – 2007
Texas Section Society for Range Management Endowment Fund Chair, 2005 – Present
Prescribed Grazing Committee – Amer. Sheep Ind. Assoc., 2006 – present
Producer Education and Research Council Member – Amer. Sheep Ind. Assoc., 2004 – 05
Board of Directors Texas Section Society for Range Management, 2002 – 2004
Public Affairs Committee Society for Range Management Chair, 2003 – 2004
Associate Editor Journal of Range Management, 1996-2000
President Idaho Section Society for Range Management, 1992
Land Use Committee Western Section Society of Animal Science, 1990 -1992
President TAMU Student Chapter of Wildlife Society, 1975 – 1976


CIVIC ACTIVITIES:

Friends of San Angelo State Park Advisory Board 2010 – Present
San Angelo Convention and Visitors Board 2002 – 2008, Chair 2006 – 2007
Chair San Angelo Annual Sheep Run Committee 2003 – 2005
Member Board of Directors Clark County Day Care Center 1995
Dubois, ID Rodeo Committee 1989 – 1993
Member Clark County, ID Land Use and Planning Board 1995
Clark County School Board of Trustees 1989 – 1992, Chair 1992
Vice President Seymour, TX Jaycees 1983
Seymour Rodeo Association Board Member 1983 – 1985



PUBLICATIONS


Journal

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.

Frost, R., J. Walker, C. Madsen, R. Holes, J. Lehfeldt, J. Cunningham, K. Voth, B. Welling, T. Z. Davis, D. Bradford, J. Malot and J. Sullivin. 2012. Targeted Grazing: Applying the Research to the Land. Rangelands. 34:2-10.

Hanovice-Ziony, M., N. Gollop, S.Y. Landau, E.D. Ungar, H. Muklada, T.A. Glasser, A. Perevolotsky, and J.W. Walker. 2010. No major role for salivary tannin-binding in the defense of browsing goats against dietary tannins. J. Chemical Ecology. 36:736–743.

Wilcox, B.P., J.W. Walker, and J.L. Heilman. 2010. Commentary on “Effect of brush control on evapotranspiration in the North Concho River watershed using the eddy covariance technique” by Saleh et al. (2009). J. Soil Water Conserv. 65: 83A-84A.

Campbell, E.J., R.A. Frost, T.K. Mosley, J.C. Mosley, C. J. Lupton, C.A. Taylor Jr., J.W. Walker, D.F. Waldron, and J. Musser. 2010. Pharmacokinetic differences in exposure to camphor after intraruminal dosing in selectively bred lines of goats. J. Anim. Sci. 88: 2620-2626.

Utsumi, S.A., A.F. Cibils, R.E. Estell, T.T. Baker, and J.W. Walker. 2010. One-seed juniper sapling use by goats in relation to stocking density and mixed grazing with sheep. Rangeland Ecol. Manage. 63:373-386.

Bailey, D.W, M.G. Thomas, J.W. Walker, B.K. Witmore and D. Tolleson. 2010. Effect of previous experience on grazing patterns and diet selection of Brangus cows in the Chihuahuan Desert. Rangeland Ecol. Manage. 63:223-232.

Glasser, T.A., E.D. Ungar, S.Y. Landau, A. Perevolotsky, M.H. Muklada, J.W. Walker. 2009. Breed and maternal effects on the intake of tannin-rich browse by juvenile domestic goats (Capra hircus). Appl. Anim. Behav. Sci. 119:71-77.

Lupton, C. J., E. S. Campbell, B. S. Engdahl, T.  D. Lovett, F. A. Pfeiffer, C. A. Taylor, Jr., D. F. Waldron, and J. W. Walker. 2009. Selecting Angora goats to consume more juniper. Tropical and Subtropical Agroecosystems J. 11:59-64.

Waldron, D. F., C. A. Taylor, Jr., J. W. Walker, E. S. Campbell, C. J. Lupton, T. D. Willingham, and S. Y. Landau. 2009. Heritability of juniper consumption in goats. J. Anim. Sci. 87: 491-495.

Musser, J.M., C.A. Taylor, J. Guo, I.R. Tizard and J.W. Walker. 2008. Development of a contagious ecthyma vaccine for goats. Amer. J. Vet. Res. 69:1367- 1370.

Glasser, T., S. Landau, E.D. Ungar, A. Perevolotsky, L. Dvash, H. Muklada, D. Kababya and J.W. Walker. 2008. A fecal near-infrared reflectance spectroscopy-aided methodology to determine goat dietary composition in a Mediterranean shrubland. J. Anim. Sci. 86:1345-1356.

Wilcox, B.P., Y. Huang and J.W. Walker. 2008. Long-term trends in streamflow from semiarid rangelands: uncovering drivers of change. Global Change Biology. 14: 1676-1689.

Campbell, E.S., C.A. Taylor, J.W. Walker, C.J. Lupton, D.F. Waldron and S.Y. Landau. 2007. Effects of supplementation on juniper intake by goats. Rangeland Ecol. Manage. 60:588-595.

Fraker-Marble, M. J., K. L. Launchbaugh and J.W. Walker. 2007. Differences in food ingestion and digestion among sheep classified as high or low sagebrush consumers. Rangeland Ecol. Manage. 60: 191-194

Kronberg, S.L and J.W. Walker. 2007. Learning through foraging consequences: a mechanism of feeding niche separation in sympatric ruminants. Rangeland Ecology and Manage. 60: 195-198

Walker, J.W., E. S. Campbell, C. J. Lupton, C. A. Taylor Jr., D. F. Waldron, and S. Y. Landau. 2007. Effects of breed, sex, and age on the variation and ability of fecal near-infrared reflectance spectra to predict the composition of goat diets. J. Anim. Sci. 85: 518-526.

Landau S., T. Glasser, H. Muklada, L. Dvash, A. Perevolotsky, E.D. Ungar, and J.W. Walker. 2005. Fecal NIRS prediction of dietary protein percentage and in vitro dry matter digestibility in diets ingested by goats in Mediterranean scrubland. Small Rumin. Res. 59:251-263.

Ellis, C.R., R.E. Jones, C.B. Scott, C.A. Taylor, J.W. Walker, and D.F. Waldron. 2005. Sire influence on juniper consumption by goats. Rangeland Ecol. Manage. 58:324 – 328.

Johnson, D.A., N.Z. Saliendra, J.W. Walker, and J.R. Hendrickson. 2003. Bowen ratio versus canopy chamber CO2 fluxes on sagebrush rangeland. J. Range Manage. 56:517-523.

Frost, R.A., C.B. Scott, J.W. Walker, and F.S. Hartmann. 2003. Effects of origin, experiences early in life, and genetics on bitterweed consumption by sheep. Appl. Anim. Beh. Sci. 84:251-264.

Walker, J.W., S.D. McCoy, K.L. Launchbaugh, Fraker, M.J. and J. Powell. 2002. Calibrating fecal NIRS equations for predicting botanical composition of diets.  J. Range Manage. 55:374-382.

Stellflug, J.N., Hatfield, P.G., Wulster-Radcliffe, M.C., and J.W. Walker. 2001. Reproductive performance of ewe lambs from ewes from different selection practices with or without induced estrus. Anim. Reprod. Sci. 66:185-193.

Snowder G.D., J.W. Walker, K. L. Launchbaugh and L. D. Van Vleck. 2001. Genetic and phenotypic parameters for dietary selection of Mountain Big Sagebrush (Artemisia tridentata Nutt. ssp. vaseyana (Rydb) Beetle) in Rambouillet sheep. J. Anim. Sci. 79:486-492.

Bork, E.W. N.E. West, K.P. Price and J.W. Walker. 1999. Rangeland cover component quantification using broad (TM) and narrow-band (1.4 nm) spectrometry. J. Range Manage. 52:249-257.

Hatfield, P.G., J. Stellflug, J.W. Walker and R.W. Kott. 1999. The effects of nutritional management on ewe and lamb bodyweight and ewe body composition.  Sheep & Goat Res. J. 15:41-49.

Kronberg, S.L. and J.W. Walker. 1999. Sheep preference for leafy spurge from Idaho and North Dakota. J. Range Manage.  52:39-44.

Walker, J.W., D.H. Clark, and S.D. McCoy.  1998.  Fecal NIRS for predicting percent leafy spurge in diets.  J. Range. Manage.  51: 450-455.

Bork, E.W., N.E. West and J.W. Walker. 1998. Cover components on long-term seasonal sheep grazing treatments in three-tip sagebrush steppe. J. Range Manage. 51:293-300.

Kay, C.E. and J.W. Walker. 1997. A comparison of sheep- and wildlife-grazed willow communities in the greater Yellowstone ecosystem. Sheep and Goat Res. J. 13:6-14.

Heitschmidt, R.K. and J.W. Walker. 1996. Grazing management: Technology for sustaining rangeland ecosystems?. Rangelands. 18:194-215.

Kronberg, S.L., W.C. Lynch, C.D. Cheney and J.W. Walker. 1995 Potential aversive compounds in leafy spurge for ruminants and rats. J. Chem. Ecol. 21:1387-1399.

Walker, J.W. 1995. Viewpoint: Grazing management and research now and in the next millennium.  J. Range Manage. 48:350-357.

Walker, J.W., S.L. Kronberg, S.L. Al-Rowaily, and N.E. West. 1994. Comparison of sheep and goat preferences for leafy spurge.  J. Range Manage. 47:429-434.

Walker, J.W. 1994.  Multispecies grazing: The ecological advantage.  Sheep Res. J.  Special Issue. 52-64.

Walker, J.W. 1993.  Nutritional models for grazing animals. Icel. Agric. Sci. 7:45-57.

Walker, J.W., H.A. Glimp, S.L. Kronberg, and T.R. Kellom. 1993.  When Less may mean more: Studies on range vs. shed lambing in a cold desert shrub ecosystem.  Professional Animal Scientist 9:153-158.

Kronberg, S.L., and J.W. Walker.  1993. Ruminal metabolism of leafy spurge in sheep and goats: a potential explanation for differential foraging on spurge by sheep, goats and cattle.  J. Chem. Ecol. 19:2007-2017.

Kronberg, S.L., J.W. Walker and J.A. Fitzgerald.  1993.  Feeding behavior of grazing ruminants experiencing stress.  Physiol. Behav. 54:1191-1194.

Hatfield, P.G, L. Ortega-Reyes, F.D. Provenza, J.W. Walker, H.A. Glimp.  1992.  Post-exposure performance of lambs exposed to whole barley early in life.  SID Sheep Research J. 8:91-94.

Walker, J.W., K.G. Hemenway, P.G. Hatfield, and H.A. Glimp.  1992. Training lambs to be weed eaters: studies with leafy spurge.  J. Range. Manage. 45:245-249.

McKown, D.C., J.W. Walker, J.W. Stuth and R.K. Heitschmidt. 1991. Nutrient intake of cattle on rotational and continuous grazing treatments. J. Range Mange. 44:596-601.

Hatfield, P.G., J.W. Walker, and H.A. Glimp.  1991. Comparing the captec bolus to chromic oxide dosed twice daily using sheep in confinement.  J. Range. Manage. 44:408-409.

Hatfield, P.G, J.W. Walker, H.A. Glimp, and D.C. Adams. 1990. Effect of level of intake and supplemental barley on marker estimates of fecal output using an intraruminal continuous-release chromic oxide bolus. J. Anim. Sci. 69:1788-1794.

Bailey, D.W., J.W. Walker, and L.R. Rittenhouse. 1990. Sequential analysis of cattle location: Day to day movement patterns.  Appl. Anim. Beh. Sci. 25:137-148.

Heitschmidt, R.K., J.R. Conner, S.K. Canon, W.E. Pinchak, J.W. Walker, and S.L. Dowhower. 1990. Cow/calf production and economic returns from yearlong continuous, deferred rotation and rotational grazing treatments. J. Prod. Agric. 3: 92-99.

Walker, J.W., R.K. Heitschmidt, E.A. de Moraes, M.M. Kothmann, and S.L. Dowhower.  1989. Quality and botanical composition of cattle diets under rotational and continuous grazing treatments.  J. Range Manage. 42(3):239-242.

Walker, J.W., R.K. Heitschmidt, and S.L. Dowhower.  1989. Some effects of a rotational grazing treatment on cattle preference for plant communities.  J. Range. Manage. 42 (2):143-148.

Walker, J.W. and R.K. Heitschmidt. 1988. Some effects of a rotational grazing treatment on cattle grazing behavior.  J. Range Manage. 42:337-342.

Walker, J.W., J.W. Stuth, and R.K. Heitschmidt. 1989. A simulation approach for evaluating field data from grazing trials.  Agricultural Systems. 30:301-316.

Heitschmidt, R.K., S.L. Dowhower, and J.W. Walker.  1987. 14‑ vs. 42‑paddock rotational grazing: aboveground biomass dynamics, forage production and harvest efficiency in a rotational grazing treatment. J. Range Manage.  40:216‑223.

Heitschmidt, R.K., S.L. Dowhower, and J.W. Walker.  1987. 14‑ vs. 42‑paddock rotational grazing: forage quality.  J. Range Manage.  40:315‑317.

Heitschmidt, R.K., S.L. Dowhower, and J.W. Walker.  1987. Some effects of a rotational grazing treatment on quantity and quality of available forage and amount of ground litter.  J. Range Manage.  40:318‑321.

Walker, J.W. and R.K. Heitschmidt.  1986. Effect of various grazing systems on type and density of cattle trails.  J. Range. Manage.  39:428-431.

Walker, J.W., J.W. Stuth, R.K. Heitschmidt, and S.L. Dowhower.  1985. A new esophageal plug.  J. Range Manage. 38:185‑187.

Walker, J.W., R.K. Heitschmidt, and S.L. Dowhower.  1985. Evaluation of pedometers for measuring distance traveled by cattle on two grazing systems.  J. Range Manage. 38:90‑93.

Heitschmidt, R.K. and J.W. Walker.  1983.  Short duration grazing and the Savory Grazing Method in perspective.  Rangelands 5:47‑150.

Walker, J.W., R.M. Hansen, and L.R. Rittenhouse.  1981. Diet selection of Hereford, Angus x Hereford and Charolais x Hereford cows and calves.  J. Range Manage. 34, 3:243‑245.


Books and Book Chapters

Walker, J. 2015. Forages Chapter, Section on Rangelands. In Sheep Production Handbook. 8th Edition. American Sheep Industry Association, Inc. Centennial, CO.

Walker, John and Doug Tolleson. 2010. Shining light on manure improves livestock and land management. Texas AgriLife Resarch Tech. Bull. SANG-2010-0250. Texas AgriLife Research, San Angelo, TX.

Walker, J.W. 2010. Primer on near infrared spectroscopy. Ch 1. In J. Walker, and D. Tolleson, (eds). Shining light on manure improves livestock and land management. Texas AgriLife Resarch Tech. Bull. SANG-2010-0250. Texas AgriLife Research, San Angelo, TX.

Walker, J.W., E.J. Campbell, R.W. Kott, S.Y. Landau, C.J. Lupton, C.B. Scott, L. Surber, C.A. Taylor, Jr., and W.R. Whitworth 2010. Fecal NIRS for predicting botanical composition of herbivore diets. Ch 5. In J. Walker, and D. Tolleson, (eds). Shining light on manure improves livestock and land management. Texas AgriLife Resarch Tech. Bull. SANG-2010-0250. Texas AgriLife Research, San Angelo, TX.

Landau, S., T. Glasser, E.D. Ungar, A. Perevolotsky, L. Dvash, H. Muklada, D. Kababya, and J.W. Walker. 2010. Fecal NIRS with Bite Counts: A methodology to determine the botanical and chemical composition of diets consumed by goats in a Mediterranean shrubland. Ch 6. In J. Walker, and D. Tolleson, (eds). Shining light on manure improves livestock and land management. Texas AgriLife Resarch Tech. Bull. SANG-2010-0250. Texas AgriLife Research, San Angelo, TX.

Belesky, D.P., D.W. Koch and J.W. Walker. 2007. Forbs and Browse Species. Ch. 17 in K.J. Moore R.F. Barnes, C.J. Nelson, M. Collins, (eds)  Forages: The Science of Grassland Agriculture Volume II, Sixth Edition. Blackwell Publishing, Ames Iowa.

K. Launchbaugh, J. Walker and R. Daines. 2006. Targeted Grazing – a natural approach to vegetation management and landscape enhancement. American Sheep Industry Association. Centennial, CO.

Launchbaugh, Karen and John Walker. 2006. Targeted grazing – a new paradigm for livestock management CH 1 in K. Launchbaugh, J. Walker and R. Daines eds. Targeted Grazing – a natural approach to vegetation management and landscape enhancement. American Sheep Industry Association. Centennial, CO.

Walker, J.W., Linda Coffey, and Tim Faller. 2007 Improving grazing lands with multi-species grazing. CH 6 in K. Launchbaugh, J. Walker and R. Daines eds. Targeted Grazing – a natural approach to vegetation management and landscape enhancement. American Sheep Industry Association. Centennial, CO.

Campbell, E.S., B.S. Engdahl, C.J. Lupton, C.B. Scott, C.A. Taylor, Jr., D.F. Waldron, J.W. Walker and W.R. Whitworth. 2007. The use of fecal NIRS to identify levels of consumption of the toxic shrub juniper in a selective breeding program with goats. Ch 65. In: Panter KE, Wierenga TL, and Pfister JA (eds).  Poisonous Plants:  Global Research and Solutions.  CABI Publishing, Wallingford, Oxon, UK.  665 p.


Invited Talks and Papers

Walker J., Ebert M., Pope R. and Pfeiffer. 2016. Comparison of average fiber diameter methods: Fibrelux v OFDA2000. ASI Annual Convention. 27-30 January 2016. Scottsdale, AZ.

Walker, J. W., W. Whitworth, E. Campbell, C. Taylor, D. Waldron, and C. J. Lupton. 2015. Near infrared fecal spectra for determination of percentage juniper in goat diets. 17th International Conference on Near Infrared Spectroscopy. October 18-23, 2015. Foz do Iguassu, Brazil.

Walker, J. W., C. Lupton, D. Watanabe, and A. Rigueiro. 2015. Near infrared reflectance spectroscopy for improving wool interlotting. 17th International Conference on Near Infrared Spectroscopy. October 18-23, 2015. Foz do Iguassu, Brazil.

Walker, J. W., M. Eberts, R. Pope, and F. Pfeiffer. 2014. Using near-infrared spectrometry to select for improved wool quality. Texas Sheep and Goat Raisers Association Annual Meeting. 25 – 26 July 2014. Kerrville, Texas.

Walker, J. W. 2015. Ecological applications of Near Infrared Reflectance Spectroscopy. 2015 Northwest Regional Meeting American Chemical Society. Pocatello, ID. June 21 – 24, 2015.

Walker, J. W. 2014. Near-infrared spectroscopy applications in agriculture and natural resources. 2014 TAMU-Princeton Summer School on Quantum Science and Engineering. 21 – 25 July 2014. Casper WY.

Walker, J. W. 2014. The advantages of pasture, range and forage insurance. Cattleman’s Cow-calf Clinic. 3 April 2014. Athens, Texas.

Walker, J. W. 2014. Near-infrared spectroscopy measurement of wool. ASI/NLFA Annual Convention: Weaving a Path to the Future. 22 – 25 January 2014. Charleston, SC.

Walker, J. W. 2014. Challenges and opportunities for the U.S. Sheep industry. ASI/NLFA Annual Convention: Weaving a Path to the Future. 22 – 25 January 2014. Charleston, SC.

Walker, J. W. 2014. Dealing with complexity on the Wasatch Front: Shit happens. Institute for Quantum Science and Engineering Workshop. 14 – 15 January 2014. College Station, TX.

Walker, J. W. 2014. Dealing with complexity on the Wasatch Front. 44th Winter Colloquium on the Physics of Quantum Electronics. 5 – 9 January 2014. Snowbird UT.

Mayagoitia, P. E., J. W. Walker, M. Pittarello, and D. W. Bailey. 2015. Detection of honey mesquite leaves in cattle diets using fecal near infrared spectroscopy. In Abstr. 68th Ann. Meeting. Soc.Range Manage. January 31 – February 7, 2015. Sacramento, CA, USA.

Walker, J.W. 2013. Animal nutrition from infrared reflectance measurments on feces. 2013 TAMU-Princeton Summer School on Quantum Science and Engineering. 8 – 12 July 2013. Casper WY.

Walker, J.W. 2013. Sheep, Black Swans and the future of Agriculture. In C. Schauer and J.B. Taylor [EDS.] Proceeding 2013 WERA-39-WSASAS Sheep Symposium: 19 June 2013; Bozeman, MT, USA. Bozeman, MT USA: Integrating Advanced Concepts into Traditional Practices. P. 41 – 46.

Walker, J.W. 2013. Animal nutrition from infrared reflectance measurements of feces. The 2013 TAMU-Princeton Summer School on Quantum Science and Engineering. Casper College. Casper, WY.

Walker, J.W. 2013. Sheep, Black Swans and the future of Agriculture. WERA 39 Sheep Symposium. Bozeman, MT. June 19, 2013.

Walker, J.W. 2012. Finding your way through the labyrinth of pasture range & forage insurance. Texas A&M AgriLife Research and Extension Center 39th Annual Sheep and Goat Field Day. September 6. San Angelo, TX.

Walker, J.W., C.J. Lupton, F. Pfeiffer. 2011. In search of a sourable branding fluid. American Sheep Industry Assoc. January 25 – 27. Prescott, AZ.

Walker, J.W. 2010. Livestock protection animals: what’s important, what’s not, what they cost, and are they worth it? Texas A&M AgriLife Research and Extension Center 37th Annual Sheep and Goat Field Day. September 2. San Angelo, TX.

Launchbaugh, K., J. Walker, D. Bradford, and R. Holes, 2007, Targeted grazing – a new paradigm for livestock management, Third National Conference on Grazinglands. Dec. 10-13, 2006. St. Louis, MO.

Walker, John, K. Launchbaugh, and R. Daines. 2007. Targeted grazing: A natural approach to vegetation management and landscape enhancement. American Sheep Industry Assoc. January 25 – 27. San Antonio, TX.

Walker, John. 2006. Prescription Grazing.Texas Sheep & Goat Raiser’s 91st Annual Convention. July 20 – 22. Kerville, TX.

Walker, John and Mark Moseley. 2006. Prescribed and Targeted Grazing. Texas Section Society for Range Management, Oct. 11 – 13, 2006, Del Rio, TX.

Walker, J.W., J.L. Johnson and C.A. Taylor, Jr. 2005. Challenges and opportunities for sustainable rangeland pastoral systems in the Edwards Plateau of Texas. pgs 71-79 in J.A. Milne (ed) Pastoral systems in marginal environments. Proc. Satellite workshop XXth International Grassland Congress, July 2005, Glasgow, Scotland.

Walker, J.W. 2003. Driving forces on tomorrow’s rangelands. Texas Section SRM Annual Meeting Wichita Falls, TX. Oct 16-18, 2003.

Walker, J.W. 2003. New Paradigms for Small Ruminant Management. Invited Speaker Series, Dept. Animal and Veterinary Sciences, University of Nevada Reno. October 22, 2003.

Walker, J.W. 2002. The role of livestock grazing in the new millennium. Symposium on  Livestock Grazing For Vegetation Management. Sparks NV. Sept 4 – 5, 2002.

Walker, J.W. 2000. The North Concho River Brush Control Project: Simulation output, economic analysis and implementation. Pages 20 – 24. In J. Cearly and D. Rollins (eds). Brush, water, and wildlife: a compendium of our knowledge.  Texas Agricultural Experiment Station and Texas Agricultural Extension Service, Kerrville.

Walker, J.W. and K.C. Hodkinson. 1999. Grazing management: new technologies for old problems. Proc. VI International Rangeland Congress, People and Rangelands Building the Future. Vol. 1: 424-430.

Launchbaugh, K.L., J.W. Walker and C.A. Taylor. 1999. Foraging behavior: Experience or inheritance? P. 28-35 In K.L Launchbaugh, J.C. (eds.) Grazing Behavior of Livestock and Wildlife. Idaho Forest, Wildlife & Range Experiment Station Bulletin #70. Univ. Idaho, Moscow, ID.

Walker, J.W., W.A. Dugas, F.C. Baird, S.T. Bednarz, R.S. Muttiah and R.A. Hicks. 1998. Site selection for publicly funded brush control to enhance water yield. Proc. 25th Water for Texas Conference. “Water Planning Strategies for Senate Bill 1.” Texas Water Resources Institute. TAMUS. Austin TX. P 199-207.

Walker, J.W. 1996. A new look at resource management: Changing paradigms.  U.S. Prairie Pothole Joint Venture Management Board Meeting.  March 23, Tulsa, Okla.

Walker, J.W. 1996. Rangeland management: Now and in the next millennium.  Lokey Distinguished Speaker Series and Ag Awareness Week. Texas Tech University.

Walker, J.W. and R.K. Heitschmidt. 1996. Sustainable Grazing Management.  Forage and Livestock Conference. Effective Forage and Livestock Management.  January 30-31 North Battleford and Belford, Saskatchewan Canada.

Walker, J.W. 1996. Multi-species grazing management. The 25th Annual Pacific Northwest Range Management Short Course. January 16-18, Boise Idaho

Walker, J.W. 1996.  7 Habits of highly effective resource managers.  The 25th Annual Pacific Northwest Range Management Short Course. January 16-18, Boise Idaho.

Walker, J.W. 1995. Pros and Cons of Multi-species Management. Utah Wool Growers 89th Annual Convention.  November 29 Salt Lake City.

Walker, J.W. 1995. Sheep Ecology – Making Money Using Sheep As a Management Tool.  Utah Wool Growers 89th Annual Convention.  November 29 Salt Lake City.

Walker, J.W. 1995. Long term vegetation change in the Centennial Mountains.  American Sheep Industry Annual Meeting.  Washington D.C.

Walker, J.W. 1995. Multispecies grazing. Rangeland Health Workshop. Thermopolis Wyoming.

Walker, J.W. 1995.  Testimony on 1995 Farm Bill.  Formulation of the 1995 Farm Bill. Committee on Agriculture House of Representatives. One Hundred Fourth Congress. Boise, ID. May 27, 1995. Serial No. 104-8 Part 1. pg. 852-858.

Walker, J.W. 1995. Multispecies Grazing.  Colorado Wool Growers Annual Meeting. Vale Colorado. July 28.

Walker, J.W. 1995. Sheep: Tool for healthy rangelands. Colorado Wool Growers Annual Meeting. Vale Colorado. July 28.

Walker, J.W.  1993.  Range Livestock Research in the 21st Century: Where did we come from where should we go.  46th Ann. Meeting Soc. Range Manage.  Albuquerque, NM.

Walker, J.W., 1993.  Integrated leafy spurge management.  Rocky Mountain Leafy Spurge Symposium.  Montrose, CO.

Walker, J.W. 1992. Training sheep to graze leafy spurge. 45th Meeting W. Soc. Weed Sci. Salt Lake City, UT.

Walker, J.W. 1991. Livestock as weed eaters: Principles and practical applications.  Winter Meeting Idaho Section Soc. Range Management.  Sun Valley, ID Dec 5-7.

Walker, J.W. 1991. Multi-species grazing systems.  Proc. Sheep Forage Production Systems Symposium.  Steamboat Springs, Colo. pp. 95-102.

Walker, J.W. 1990. Multispecies Grazing. Alberta Sheep Symp. December.

Walker, J.W. 1990. Nutritional models for grazing animals. Symp. Nutritional Aspects of Sheep Grazing and Feeding Under Northern Conditions. Reykjavik, Iceland.

Walker, J.W. and E.W. Richardson.  1986.  Replication in grazing studies ‑ Why bother?  pp. 51‑58 in Statistical Analyses and Modeling of Grazing Systems Symp. Proc.  February 11, 1986, Kissimmee, Florida.  Soc. for Range Manage.  Denver, CO.

Heitschmidt, R.K. and J.W. Walker.  1984.  Requirements for a grazing system that best meets ranch needs.  Proc. Inter. Ranchers Roundup.  Tex. Agric. Ext. Serv., College Station.  p. 236‑245.


Other

Redden, R. R., J. M. Tomecek, and J. W. Walker. 2015. Livestock Guardian Dogs. Texas A&M AgriLife Ext. Pub. EWF-028.

Walker, J. 2013. Creating a “Super Juniper Eating Goat”. Ranch & Rural Living 94(11): 20 -23.

Walker, J.W. 2013. Sheep, Black Swans and the future of Agriculture. In C. Schauer and J.B. Taylor [EDS.] Proceeding 2013 WERA-39-WSASAS Sheep Symposium: 19 June 2013; Bozeman, MT, USA. Bozeman, MT USA: Integrating Advanced Concepts into Traditional Practices. P. 41 – 46.

Walker, John. 2013. Pasture rangeland and forage insurance for good range management. Ranch & Rural Living 94(11): 7-11.

Lupton, C. J., F. A. Pfeiffer, W. S. Ramsey, M. Salisbury, D. F. Waldron, J. W. Walker, and T. W. Willingham. 2010. Comparison of Texas Rambouillet sheep with Australian Merino F1 crosses. Sheep Research and Outreach Symposium, American Sheep Industry Association Annual Convention, Nashville, TN, January 21:52-54.

Kott, R., Surber, L., Roeder, B., Brewer, T. and Walker, J. 2009. Developing grazing prescriptions for spotted knapweed. Proc. U.S. Sheep Research Programs. American Sheep Industry Association convention, San Diego, CA Jan 21-24, 2009. pg 45-46.

Walker, John, Sue Engdahl, Rodney Kott, Andres Cibilis, Christopher Lupton, Erika Campbell, Charles Taylor, and Daniel Waldron. 2006. Fecal near-infrared reflectance spectroscopy for predicting botanical composition of the diets of sheep and goats. Joe Skeen Institute for Rangeland Restoration Annual Meeting. September 13 – 15, Cloudcroft, NM.

Johnson, D.A., T.A. Gilmanov, N.Z. Saliendra and J.W. Walker. 1999. Carbon dioxide fluxes on control and burned sites on sagebrush-steppe rangeland in the western USA. Proc. VI International Rangeland Congress People and Rangelands Building the Future. Vol. 2: 746-747.

Walker, J.W. 1999. Range war in West Texas. Cashmirror 10:13-14.

Walker, J.W. 1999. Researcher says deer, goat conflict is not inevitable. Livestock Weekly 51(15):20.

Kronberg, S.L., Walker, J.W. and R.E. Short. 1998. Predicting ponderosa pine needle intake with NIRS and fecal samples. Proc. West. Sec. Amer. Soc. Anim. Sci. 49:

Walker, J.W., S.L. Kronberg. S.L. Al-Rowaily, and N.E. West.  1995. Managing noxious weeds with livestock: Studies on leafy spurge.  Proc. Fifth Int. Rangeland Congress.  1:586-587.

Al-Rowaily, S.L, N.E. West, and J.W. Walker. 1995. Effect of simulated defoliation and plant competition of flowering and seed yield of leafy spurge. Proc. Fifth Int. Rangeland Congress.  1:6-7.

Walker, J.W., S.L. Kronberg, S.L. Al-Rowaily, and N.E. West. 1994. Managing noxious weeds with livestock: Studies on leafy spurge. pp. 125-135. In: U.S. Dept Agric Sheep Research Progress Report No. 3.  Agric. Research Service.

Walker, J.W., H.A. Glimp, S.L. Kronberg, and T.R. Kellom.  1994.  Shed lambing favorable to multiple birhts and range lambing favorable to single births.  Animal Nutrition Research Highlights. Quarterly Publication of the American Soybean Association.  (abstracted range lambing article).

Hatfield, P.H. and J.W. Walker. 1993.  The Pred-X eartag: does it work?  Montana Woolgrower. February-March p. 28.

Kronberg, S.L., J.W. Walker and J.A. Fitzgerald.  1993.  Diet selection of grazing ruminants experiencing stress.  Proc. VII World Conference on Anim. Prod. Edmonton, Alberta.

Mosley, J.C., T.A. Lance, J.W. Walker, D.E. Lucas, and C.M. Falter. 1993. How does grazing affect water quality?  Focus Renew. Nat. Resour. Moscow, Idaho, Forest, Wildlife and Range Experiment Station.  18:5.

Walker, J.W. and S.L. Kronberg.  1992.  Managing leafy spurge with livestock.  Proc. Leafy Spurge Symposium.  Lincoln, NE. GPAC Publ. 144:4-23.

Snowder, G.D. and J.W. Walker. 1991. Range management and co-grazing with goats. Proc. IV Ann. Natl. Conf. Cashmere Producers of America.  Univ. Missouri, Columbia. Dec. 6-8, 1991 pp46-50.

Walker, J., K. Hemenway, P. Hatfield, and H. Glimp. 1990. The effect of early exposure to leafy spurge on subsequent selection.  Res. Prog. Rep., USDA, ARS, U.S. Sheep Experiment Station. pp 2-9. USDA.

Walker, J. and H. Glimp. 1990. A comparison of ewe and lamb performance on traditional mountain summer ranges and alternative spring-fall desert range. Res. Prog. Rep., USDA, ARS, U.S. Sheep Experiment Station. pp 10-13. USDA.

Walker, J., P. Hatfield, and H. Glimp. 1990. Combination grazing of sheep and cattle for more efficient utilization of range forage. Res. Prog. Rep., USDA, ARS, U.S. Sheep Experiment Station. pp 14-16. USDA.

Hatfield, P.G., Walker, J.W., and H.A. Glimp. 1990. Determining forage intake using marker estimates of fecal output. Res. Prog. Rep., USDA, ARS, U.S. Sheep Experiment Station. pp 45-47. USDA.

Hatfield, P.G., Walker, J.W., and H.A. Glimp. 1990. Forage intake and lamb performance of Targhee ewes selected to increase pounds of lamb weaned per ewe. Res. Prog. Rep., USDA, ARS, U.S. Sheep Experiment Station. pp 45-47. USDA.

Hatfield, P.G., J.W. Walker, and H.A. Glimp D.C. Adams. 1990. Effects of intake levels and supplemental barley on estimates of dry mater fecal output using a constant release chromic oxide bolus. Proc. West. Sec. Amer. Soc. Anim. Sci. 41:426-429.

Hatfield, P.G., J.W. Walker, J.A. Fitzgerald, K.J. Hemenway, and H.A. Glimp. 1993. Effects of method of estimation fecal output of grazing sheep on fecal output, weight change, and plasma cortisol concentration.  Proc. West. Sec. Amer. Soc. Anim. Sci. 40:224-227.

Hansen, D.K., F.M. Rouquette, Jr., M.J. Florence, J. Walker, and R. Heitschmidt. 1987. Grazing behavior of yearling horses. I. Time spent grazing different forages.  Tex. Agric. Exp. Sta. Consol. PR.  College Station.

Heitschmidt, R.K., S.L. Dowhower, and J.W. Walker.  1986.  Effect of livestock density (number of paddocks) in a rotational grazing system on forage production and herbage standing crop.  Tex. Agric. Exp. Sta. Consol. PR 4416‑4457.  College Station.  p. 9‑10.

Heitschmidt, R.K., S.L. Dowhower, and J.W. Walker.  1986.  Effect of rota­tional grazing on forage and litter standing crops.  Tex. Agric. Exp. Sta. Consol. PR‑4416‑4457.  College Station.  p. 10‑11.

Heitschmidt, R.K., S.L. Dowhower, and J.W. Walker.  1986.  Effect of rota­tional grazing on protein content of available forage.  Tex. Agric. Exp. Sta. Consol. PR 4416‑4457.  College Station.  p. 20‑26.

Walker, J.W. and R.K. Heitschmidt.  1986.  Grazing behavior of cattle in moderate continuous and rotational grazed systems.  Tex. Agric. Exp. Sta. Consol. PR 4416‑4457.  College Station.  p. 21‑22.

Walker, J.W. and R.K. Heitschmidt.  1986.  Effect of various grazing systems on type and density of cattle trails.  Tex. Agric. Exp. Sta. Consol. PR 4416‑4457.  College Station.  p. 22‑23.

de Moraes, E.A., M.M. Kothmann, R.K. Heitschmidt, and J.W. Walker.  1986.  Botanical and chemical composition of cattle diets from yearlong continuous and rotational grazing systems.  Tex. Agric. Exp. Sta. Consol.  PR 4416‑4457. College Station.  p. 26.

Kothman, M.M., E.A. de Moraes, R.K. Heitschmidt, and  J.W. Walker.  1986.  Botanical and chemical composition of cattle diets from yearlong continuous and rotation grazing systems.  Tex. Agric Exp Sta. Consol. PR 4416-4457.  p. 26.

Heitschmidt, R.K., J.W. Walker, W.E. Pinchak, and S.L. Dowhower. 1986.  Effect of rotational grazing on cow‑calf performance.  Tex. Agric. Exp. Sta. Consol. PR 4416‑4457.  College Station.  p. 32‑33.

McKown, C.D., J.W. Stuth, R.K. Heitschmidt, and J.W. Walker.  1986.  Nutrient intake of steers in continuous and rotational grazing systems.  Tex. Agric. Exp. Sta. Consol. PR 4416‑4457.  College Station. p. 39‑40.

Conner, J.R., R.K. Heitschmidt, and J.W. Walker.  1986.  Economic analysis of four grazing strategies.  Tex. Agric. Exp. Sta. Consol. PR 4416‑4457.  College Station. p. 53.

Walker, J.W.  1984.  Grazing management theories and their application to short duration grazing.  Proc. Amer. Forage Grassland Conference.  pp. 176‑180.

Johnson, A.B. and J.W. Walker.  1983.  Variation of nutrient flow at the abomasum.  Tex. Agric. Exp. Sta. PR‑4092.

Johnson, A.B., R.K. Heitschmidt, J.W. Walker, and O. Shipman.  1983.  Potassium supplementation of cows in the Rolling Plains.  Tex. Agric. Exp. Sta. PR‑4073.

Johnson, A.B., L.W. Varner, and J.W. Walker.  1983.  Method of phosphorus supplementation and blood serum response.  Tex. Agric. Exp. Sta. PR‑4072.

Johnson, A.B., R.K. Heitschmidt, J.W. Walker, and J.R. Frasure.  1983.  Growth of implanted calves suckling first calf heifers.  Tex. Agric. Exp. Sta. PR‑ 4069.

Cook, C.W., J.W. Walker, M.H. Ebberts, L.R. Rittenhouse, E.T. Bartlett, D.A. Cramer, P.T. Fagerlin, and M.C. McKean.  1982.  Alternate grass and grain feeding systems for beef production.  Colo. State Univ. Exp. Sta. Bull. No. 5795.

Johnson, A.B., R.K. Heitschmidt, J.W. Walker, and J.R. Frasure.  1982.  Growth of calves suckling first calf heifers.  Proc. West. Sec. Amer. Soc. Anim. Sci. 34:174‑176.

Walker, J.W., R.K. Heitschmidt, A.B. Johnson and S.L. Dowhower.  1982.  Short duration grazing at the Texas Experimental Ranch: Animal behavior.  pp. 178‑181 in D.D. Briske and M.M. Kothmann (eds.), Proc. Natl. Symp. Grazing Manage. Technology.  Texas A&M Univ., College Station.

Johnson, A.B., R.K. Heitschmidt, J.W. Walker, and S.L. Dowhower.  1982.  Short duration grazing at the Texas Experimental Ranch: Forage and diet quality.  pp. 176‑177 in D.D. Briske and M.M. Kothmann (eds.), Proc. Natl. Symp. Grazing Manage. Technology.  Texas A&M University, College Station.

Dowhower, S.L., R.K. Heitschmidt, J.W. Walker, and A.B. Johnson.  1982.  Short duration grazing at the Texas Experimental Ranch: Aboveground biomass dynamics and net primary production.  pp. 172‑175 in D.D. Briske and M.M. Kothmann (eds.), Proc. Natl. Symp. Grazing Manage. Technology.  Texas A&M University, College Station.

Heitschmidt, R.K., A.B. Johnson, J.W. Walker, and S.L. Dowhower.  1982.  Short duration grazing at the Texas Experimental Ranch:  Livestock production.  pp. 168‑171 in D.D. Briske and M.M. Kothmann (eds.), Proc. Natl. Symp. Grazing Manage. Technology.  Texas A&M University, College Station.

Cook, C.W., J.W. Walker, M.H. Ebberts, L.R. Rittenhouse, E.T. Barlett, D.A. Cramer, P.T. Fagerlin, and M.C. McKean.  1981.  Alternative grass and grain feeding systems for beef production Nutritional regimen.  Bull. Colo. State Univ. Exp. Stn. Fort Collins, CO., The Station. July 1981. (579S) 102 p.

Walker, J.W.  1981.  Influence of nutritional regimen and biological type on production carcass and palatability characteristics of steers.  MS Thesis.  Colo. State University, Fort Collins, CO.


Abstracts

Walker, J.W. 2013. All animals used in targeted grazing have been elected: now it is time to target selection to enhance their efficacy as targeted gazers. In Abstr. 66th Ann. Meeting. Soc.Range Manage. February 2-8, Oklahoma City, OK.

Tidwell, Kendall, Cody Scott, Charles Taylor, John Walker, Dan Waldron, Corey Owens, Micheal Salisbury. 2011. Will Super Juniper-Eating Sires Produce Super JuniperEating Offspring?, In Abstr. 64th Ann. Meeting Soc. Range Manage. February 12-17, Billings, MT.

Lupton, C. J., F. A. Pfeiffer, W. S. Ramsey, M. Salisbury, D. F. Waldron, J. W. Walker, and    T. D. Willingham. 2010. Comparison of Rambouillet sheep with Australian Merino F1 crosses.  J. Anim. Sci. 88, E-Suppl. 2:170.

Lupton, C. J., F. A. Pfeiffer, W. S. Ramsey, M. Salisbury, D. F. Waldron, J. W. Walker, and T. D. Willingham. 2009. Preliminary results of a comparison between Texas Rambouillet sheep and Australian Merino F1 crosses. J. Anim. Sci. 87, E-Suppl.2:307.

Lupton, C.J., E. S. Campbell, B. S. Engdahl, T. D. Lovett, F. A. Pfeiffer, C. A. Taylor, Jr., D. F. Waldron, and J. W. Walker. 2008. Selecting Angora goats to consume more juniper. Proc. 9th Int. Conf on Goats, Queretaro, Mexico,  August 31 – September 5. Abstract 67:95-96.

Walker J. W., E. S. Campbell, D. F. Waldron, C. J. Lupton, C. A. Taylor, Jr., B.S. Engdahl, and S. Y. Landau. 2008. periodicities in consumption of chemically defended plants.  Joint Mtg. Soc. Range Manage. & Amer. Forage & Grass Council. Louisville, KY. January 26 – 31.

Prince, S., D. Tolleson, C. J. Lupton, J. W. Walker, K. Rater, E. Earlywine, and E. Wiedower. 2008. Evaluation of mohair fleece fineness prior to shearing via field-portable near-infrared reflectance spectroscopy instruments.  Amer. Soc. Anim. Sci. South. Sec. Abstracts:31.

Bailey, D.W. M.G. Thomas, J.W. Walker and C.C. Bailey. 2007. Effect of previous experience on grazing patterns of Brangus cattle in the Chihuahuan desert. In Abstr. 60th Ann. Meeting Soc. Range Manage. February 12-17, Reno, NV.

Frost, R., Campbell, E.S., Brewer, T.K., Mosley, J.C., Taylor, C.A., Walker, J., Waldron, D.F., Lupton, C.L. (2008). Pharmacokinetic differences in high and low juniper consuming goats. 61st Annual Meeting American Society Range Management, 25-31 January 2008, Lexington (KY, USA).

Walker, J.W. and S. Landau. 2007. Predicting botanical composition of diets with fecal NIRS. In Abstr. 60th Ann. Meeting Soc. Range Manage. February 12-17, Reno, NV.

Walker, J.W., C.A. Taylor, Jr and E. Campbell.  2006.  Brush and woody weed management with sheep and goats.  In Abstr. 59th Ann. Meeting Soc. Range Manage. February 12-17, Vancouver, British Columbia.

Hendrickson, J.R., D.A. Johnson, N. Saliendra, J.W. Walker, and H. Blackburn. 2003. Big Sagebrush leaf area dynamics on a burned, grazed and control site in the Sagebrush Steppe. In Abstr. 56th Ann. Meeting Soc. Range Manage. February 2-6, Casper, WY. (Poster).

Whitworth, W, C. Scott, J. Walker, C. Taylor, S. Engdahl, and C. Lupton. 2003. Sources of variation for fecal nirs equations for predicting percent juniper in goat diets.  In Abstr. 56th Ann. Meeting Soc. Range Manage. February 2-6, Casper, WY.

Walker, J.W. 2002. A new paradigm for small ruminant production. J. Anim. Sci. 81 Suppl. 1:175.

Walker, J.W., G.D. Snowder, K.L. Launchbaugh, S.D. McCoy and M.J. Fraker. 2001. Use of NIRS of fecal samples to estimate heritability of sagebrush preference. pg. 417 In Abstr. 54th Ann. Meeting Soc. Range Manage.

Glidewell, B.C., J.C. Mosley, and J.W. Walker. 2001. Sheep and cattle response when grazed together on sagebrush-grass rangeland. p. 115. In  Abstr. Meeting Western Section ASAS June 20-22, Montana State Univ. Bozeman.

Johnson, D.A., T.A. Gilmanov, N.Z. Saliendra, and J.W. Walker. 1998. p. 29. Carbon dioxide fluxes on sagebrush-steppe rangelands in northern Idaho.  Soc. for Range Manage Abstr.

Glidewell, B.C., J.C. Mosley, and J.W. Walker. 1996. Forage partitioning between sheep and cattle grazing sagebrush-grasslands in southeastern Idaho.In Abstr. 49th Ann. Meeting Soc. Range Manage.

Al-Rowaily, S.L., J.W. Walker and N.E. West. 1995. Influence of defoliation and competition on growth of leafy spurge (Euphorbia esula l.) And associated vegetation over a three year period. pg. 1 In Abstr. 48th Ann. Meeting Soc. Range Manage.

Al-Rowaily, S.L., N.E. West, and J.W. Walker. 1994. Response of leafy spurge to defoliation and composition. Abstracts from Leafy Spurge Symposium, Bozeman Montana, July 26-29. p.1

Kronberg, S.L., W.C. Lync Walker, J.W., 1994. Potential aversion-inducing compounds in leafy spurge. Abstracts from Leafy Spurge Symposium, Bozeman Montana, July 26-29.  p.16

Walker, J.W., S.L. Kronberg, S.L. Al-Rowaily, and N.E. West. 1994. Factors affecting leafy spurge preference by livestock.  Abstracts from Leafy Spurge Symp., Bozeman Montana, July 26-29 p.41

Kronberg, S.L., J.W. Walker. and C.D. Cheney.  1994. Learning as a proximate causual mechanism of feeding niche seperation in sympatric herbivores.   In Abstr. 47th Ann. Meeting Soc. Range Manage.

Pinchak, W., D. Tolleson, R. Heitschmidt and J. Walker.  1994. Effect of management systems on culling rate of young beef cows in the southern mixed grass prairie.   In Abstr. 47th Ann. Meeting Soc. Range Manage.

Walker, J.W. and S.L. Kronberg. 1992. Preference for leafy spurge by sheep compared to goats.  In Abstr. 45th Ann. Meeting Soc. Range Manage.

Kronberg, S.L., J.W. Walker and R.J. Lorenz. 1992. Differential grazing of leafy spurge by sheep in Idaho and North Dakota. In Abstr. 45th Ann. Meeting Soc. Range Manage.

Blackburn, H.D., H. Glimp, J.W. Walker, and G.D. Snowder. 1991. Comparing flock productivity on mountain and sagebrush ranges. Abstr. Ann. Meeting Amer. Soc. Anim. Sci.

Hatfield, P.G., J.W. Walker, K.J. Hemenway, and H.A. Glimp. 1989.  Effects of method of estimating fecal output of grazing sheep on fecal output, weight change, and plasma cortisol concentration.  J. Anim. Sci. 67 (Suppl.2):194-195.

Walker, J.W.  1988.  A simulation model for predicting cattle performance and  energetics on continuous and rotational grazing systems.  In Abstr. 41st Ann. Meeting Soc. Range Manage.

Walker, J.W., R.K. Heitschmidt, and J.W. Stuth.  1987.  The effect of grazing  systems on livestock distribution.  In Abstr. 40th Ann. Meeting Soc. Range  Manage.

Walker, J.W., R.K. Heitschmidt, J.W. Stuth, and S.L. Dowhower.  1986.  Effects of rotational grazing on cattle behavior. In Abstr. 39th Ann. Meeting Soc. Range Manage.

Heitschmidt, R.K., J.W. Walker, W.E. Pinchak, S.K. Canon, and S.L. Dowhower.  1986.  Effects of rotational grazing on cow/calf performance.  In Abstr. 39th Ann. Meeting Soc. Range Manage.

Dowhower, S.L., R.K. Heitschmidt, and J.W. Walker.  1986.  Effects of rota­tional grazing on aboveground biomass dynamics and ANPP.  In Abstr. 39th Ann. Meeting Soc. Range Manage.

Stuth, J.W., C.D. Mckown, R.K. Heitschmidt, and J.W. Walker.  1986.  Effects of rotational grazing on nutrient intake In Abstr. 39th Ann. Meeting Soc. Range Manage.

Conner, J.R., R.K. Heitschmidt, and J.W. Walker.  1986.  Effects of rotational grazing on economic profit In Abstr. 39th Ann. Meeting Soc. Range Manage.

Kothmann, M.M., E.A. de Moraes, R.K. Heitschmidt, and J.W. Walker.  1986.  Diet selection and quality under rotational grazing in Texas.  In Abstr. 39th Ann. Meeting Soc. Range Manage.

Heitschmidt, R.K., J.W. Walker, S.L. Dowhower, and W.E. Pinchak.  1985.  Cow‑ calf performance and grazing management at the Texas Experimental Ranch.  In Abstr. 38th Ann. Meeting Soc. Range Manage.

Heitschmidt, R.K. and J.W. Walker.  1982.  Short duration grazing and the Savory grazing method in perspective.  Joint Ann. Meeting of Texas Sections, Soc. Range Manage. and Soc. Wildlife Manage., Austin, TX. (Abstract).

Johnson, A.B., R.K. Heitschmidt, J.W. Walker, and J.R. Frasure. 1982. Variation of nutrient flow at the abomasum over a 24 hour period on free-grazing steers. J. Anim. Sci. 55(Suppl. 1):434(Abstr).

Walker, J.W., R.K. Heitschmidt, A.B. Johnson, and S.L. Dowhower.  1982.  Short duration grazing at the Texas Experimental Ranch: Animal behavior.  In Abstr. 36th Ann. Meeting Soc. Range Manage.

Dowhower, S.L., R.K. Heitschmidt, J.W. Walker, and A.B. Johnson.  1982.  Short duration grazing at the Texas Experimental Ranch: Aboveground biomass dynamics and net primary production.  In Abstr. 36th Ann. Meeting Soc. Range Manage.

Walker, J.W., L.R. Rittenhouse, and C.W. Cook.  1981.  Production of accept­able forage fed beef.  In Abstr. 34th Ann. Meeting Soc. Range Manage.

Walker, J.W.  1979.  The usefulness of optimal foraging theories in under­standing the dietary processes of cattle.  In Abstr. 32nd Ann. Meeting Soc. Range Manage.

Walker, J.W., L.R. Rittenhouse, and P.T. Fagerlin.  1979.  Cattle responses to complementary and native range grazing systems.  In Abstr. 32nd Ann. Meeting Soc. Range Manage.

Walker, J.W., P.L. Sims, and P.T. Fagerlin.  1978.  The effect of body size on beef production from a complementary grazing system.  In Abstr. 31st Ann. Meeting Soc. Range Manage.

 

Current Funded Research:

2006 ($200,000) NRCS-GLCI – Bio-Control of Invasive Plants Using Sheep and Goats C0_PI with American Sheep Industry Association

2005 ($46,243) National Sheep Industry Improvement Center- Prescribed Grazing for Vegetation Management: A Handbook for Sheep and Goat Producers and Land Managers

2005 ($74,000) Joe Skeen Institute for Rangeland Restoration

2004 ($165,000) The United States Israel Binational Agricultural Research and Development Fund – Goats for Maximal Efficiency of Brush Control

2006 ($38,000) Texas Food and Fiber Commission – Improving the Use Of Goats to Manage Juniper Co-PI

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