Final Report for EW04-004

Developing a Handbook for Utilizing Livestock as a Tool in Noxious Weed Control in Nine Western States

Project Type: Professional Development Program
Funds awarded in 2004: $90,133.00
Projected End Date: 12/31/2008
Matching Non-Federal Funds: $39,953.00
Region: Western
State: Nevada
Principal Investigator:
Jason Davison
University of Nevada Cooperative Extension
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Project Information


A handbook concerning livestock grazing as a noxious weed control method was developed and distributed to 1656 individuals located in 14 states. The handbook was presented at 11 meetings, selected for inclusion into the Bureau of Land Management’s National Integrated Pest Management curriculum and taught to 240 employees, made available online, and incorporated as a chapter in a published book concerning targeted grazing. An evaluation involving users of the handbook (N=313) revealed that 95% of the respondents rated the handbook somewhat to very useful and 92% indicated the handbook increased their knowledge of livestock grazing for noxious weed control.

Project Objectives:

The objectives for this project were to: 1) compile a list of noxious weed species for California, Colorado, Idaho, Montana, Nevada, Oregon, Washington, Wyoming and Utah, 2) collect, review, and summarize current knowledge about livestock grazing as a control method for each noxious weed species, 3) present this information in a handbook and distribute to Cooperative Extension (CE) personnel, Natural Resource Conservation Service (NRCS) employees, and others, and 4) evaluate the usefulness of the handbook.
The project objectives were to be accomplished by: 1) conducting an in-depth literature review, interviews with researchers, and a survey of grazing management practitioners to generate a knowledge base regarding livestock grazing as a control agent for specific noxious weeds, 2) presenting the information in a handbook (binder and CD formats) which describes the effectiveness of grazing as a control method for each noxious weed species, 3) producing and distributing to every CE and NRCS office in the targeted states, plus additional copies to other entities, 4) developing an interactive website featuring the handbook and other related information, 5) presenting the project at weed management conferences in the targeted states and at three national meetings, 6) publishing a synthesis, science-based paper in a peer reviewed journal, and 7) evaluating project impact through telephone surveys of handbook recipients, monitoring the number of hits on the project website, and tracking information requests.


Invasion by exotic plant species is considered one of the most significant ecological
threats of the modern era — rivaling ozone depletion, global warming, and loss of
biodiversity. In western North America, noxious weeds such as spotted knapweed
(Centaurea maculosa), leafy spurge (Ephorbia esula), yellow starthistle (C.
solstitialis), and rush skeletonweed (Chondrilla juncea) pose a significant threat to the
environment. Their invasion into western wild lands often results in reduced biodiversity,
increased soil erosion, degradation of wildlife habitat, and reduced carrying capacity for

Wildland weeds are difficult to control. Herbicides, insects, pathogens, cultural
practices, and fire have not effectively contained the spread of many of these weeds. A
major challenge is the cost and feasibility of treating vast landscapes. Classical
biological control, using insects and microbes can be effective, but it is limited by
ecological concerns and takes considerable time to develop. An underused and readily
available method for weed control is domestic livestock grazing.

Prescribed livestock grazing is the intentional use of livestock to achieve vegetation
management goals. Many studies and established programs show that grazing weeds
at a specific time, duration, and intensity can effectively reduce their abundance. The
effectiveness of prescription grazing by sheep and goats has been clearly demonstrated
in several western states for the management of leafy spurge, spotted knapweed, and
yellow starthistle. Prescribed grazing can also be integrated with herbicides, fire, or
traditional biocontrol methods to improve the efficacy and longevity of weed control

Prescribed grazing can damage weeds in several ways. Grazing in the early spring will
remove new growth, requiring the plant to utilize root and crown reserves while
significantly reducing photosynthesis and subsequent food production. If continued for
long enough, the plant is weakened and may die. Grazing later in the spring can prevent
flowering and seed formation, reducing the opportunity for seed production. Grazing the
target weed during the growing season can stress the weed while allowing desirable
plants to grow with reduced competition. Fall grazing can disrupt the flow of plant
nutrients to the roots and crowns of the plant and, as a result, reduce carbohydrate
reserves necessary for subsequent spring growth.

In some instances, noxious weeds can be excellent forage. For example, sheep and
goats readily graze leafy spurge, do well on it, and select it over grass. In other
situations, grazing animals might only graze noxious weeds as a last resort after all
other forages have been consumed. In these instances, care must be taken to avoid
long term damage to desirable vegetation. Maintaining a healthy population of desirable
plants, such as perennial grass, is a key to controlling noxious weeds on a site.

While numerous studies and well-established programs clearly demonstrate the
effective application of prescription grazing, it is an underutilized weed management
tool. Obstacles to its adoption include land managers’ ignorance about potential
application, lack of information related to animal production systems designed for
vegetation management, limited familiarity with developing grazing prescriptions, and
challenges in drafting contracts for vegetation management. Information on how to
accomplish prescription grazing for vegetation management is currently available in a
few scientific articles, book chapters, and symposia, but information provided by
professional grazing practitioners has not been assembled.

The purpose of this project was to summarize information concerning the use of livestock grazing to control important noxious weeds in nine western states, package the information in a readily useable format, and to dessiminate to targeted audiences.


Click linked name(s) to expand
  • Ed Smith
  • Linda Wilson

Education & Outreach Initiatives



A preliminary list of species was compiled by reviewing noxious weed lists from California, Colorado, Idaho, Montana, Nevada, Oregon, Utah, Washington, and Wyoming. Weeds were considered for inclusion in this project if they appeared on at least two of the selected states’ noxious weed lists. This resulted in 66 species being addressed in this project.

A draft survey instrument of 27 questions was developed and reviewed by six individuals involved in utilizing livestock for weed control activities in six different states. Their comments and suggestions were incorporated into the final survey instrument. Two versions of the survey were developed — one for researchers and the other for grazing practitioners and weed managers.

A list of potential survey participants was developed by contacting every Cooperative Extension weed specialist in the target states. Other individuals were selected based on the authors’ knowledge of professional weed managers located in the western states, articles in popular publications identifying individuals involved in weed management using livestock, and a practitioner list published on a website that is maintained by an individual involved in using livestock for vegetation management. The list was expanded during the survey period by including individuals recommended by “word of mouth” from survey respondents. The final list of potential respondents included 288 individuals. The survey was conducted over a five-month period and resulted in a 28 percent response rate (i.e., 80 returned surveys).

The information used to develop grazing guidelines came from two sources. The first was a survey administered over the phone and by email to individuals who were: a) researchers experienced in using livestock as a weed management tool, b) grazing practitioners who utilize livestock in commercial vegetation management enterprises, or c) weed management professionals who had experience in the use of livestock to manage weeds. The second source included research reports, university or agency fact sheets, websites, and referred journal articles. Grazing guidelines were developed for 26 noxious weed species for which literature or survey data provided evidence of the effectiveness of livestock grazing as a management tool. The grazing guidelines are a melding of the information reported in the literature and survey, combined with the knowledge of the authors.

The grazing guidelines were published in a handbook and on CD. A guideline was prepared for each weed species and included a picture and description of the weed and grazing prescription. The prescription included: 1) recommended type of animal, 2) animal class, 3) plant growth stage for treatment, 4) palatability of the weed, 5) effectiveness of the grazing treatment, 6) plant response, 7) grazing objective, 8) number of treatments per year, 9), number of treatment years, 10) practicality of grazing, 11) recommendation as a control method, 12) potential integration with other control methods, 13) information sources, 14) degree of agreement between literature and survey results, and 15) summary. The manual also included a summary table of the guidelines and all the literature utilized in developing the manual.

The handbook was peer reviewed and published in 2006. A CD of the handbook content was included and 2000 copies of the manual and CD were printed. To date 1656 copies of the handbook have been distributed to individuals or offices in 14 states. Requests for copies of the handbook are still being received and will be filled until the supply is exhausted.

A scientific paper was produced. The original proposal was to publish it as a review article in a refereed journal to strengthen the acceptance of the concept by the scientific community. However, the authors were asked to publish the article as a chapter in a rigorously peer reviewed book featuring targeted grazing concepts and applications. The decision was made to pursue this publication venue due to the wider audience and exposure the book (and our chapter) would receive.

The handbook and the book chapter were included as an integral part of a targeted grazing website developed and maintained by the University of Idaho’s Department of Rangeland Ecology and Management. The book chapter is also included on an interactive website hosted by the American Sheep Institute titled “Targeted Grazing-A Natural Approach to Landscape Enhancement”.

The primary educational activities that occurred following distribution of the handbook were presentations at professional meetings and workshops. The manual was presented at the following professional /technical meetings: 1) California Invasive Plant Council Annual Meeting Sonoma, CA October 5-7, 2006, 2) Cooperative Weed Management Area/Colorado Section Society for Range Management Meeting, Grand Junction, CO December 5-6, 2006, 3) Oregon Vegetation Management Association Conference Pendleton, OR September 26-28, 2006 4) Association of Natural Resource Extension Professionals, Park City, UT May 15-17, 2006, 5) Washington State Weed Conference, Yakima, WA November 1-3, 2006, 6) Wyoming Weed Association Meeting, Casper, WY November 8-9, 2006, 7) Society for Range Management Annual Meeting Reno, NV February, 9-16, 2007, 8) Montana Weed Control Association Meeting, Helena, MT January 16-18, 2007, 9) Idaho Weed Conference, Nampa, ID January 31-Feburary 1, 2007, 10) Nevada Weed Management Association Meeting Las Vegas, NV, October 9-11, 2007, and the 11) New American Farm Conference, Kansas City, Kansas March 26, 2008. The handbook was presented as part of the BLM Integrated Pest Management course in Albuquerque, NM (January 24, 2007), Billings, MT (February 28th, 2007), and Lakewood, CO (April 4, 2007). It was also presented to BLM staff in 2008 at Boise, ID (January 30), Salt Lake City, UT (March 5), and Lakewood, CO (April 9). The handbook was presentedat the National Conference on Grazing Lands in St. Louis, MO on December 10-13, 2006. Registered attendance at all the meetings where the handbook was presented exceeded 5000 individuals.

The evaluation process described in the grant was modified and consisted of a mail survey sent to 1036 locations in 13 states. The survey was sent to every address on file where handbooks had been sent previously. Many individuals requested multiple copies of the handbook which accounts for the discrepancy in numbers of handbooks distributed and numbers of addresses on file. The valid survey return rate was 30.2% (313 valid surveys) which is considered a very satisfactory response rate. The results were analyzed using descriptive statistical procedures.

Outreach and Publications

Davison, J., E. Smith and L. Wilson. 2006. Livestock Grazing Guidelines for Controlling Noxious Weeds in the Western United States. UNCE Extension Bulletin EB 06-05. Nevada Cooperative Extension, University of Nevada. Reno, NV.

Wilson, L., J. Davison, and E. Smith. 2006. Chapter 15: Grazing and Browsing Guidelines for Invasive Rangeland Weeds.(In) Targeted Grazing: A Natural Approach to Vegetation Management and Landscape Enhancement. Launchbaugh, K.L., R.J. Daines, and J.W. Walker [Eds.]. American Sheep Industry Association. Centennial, CO.

The manual and handbook was presented at 18 scientific meetings and classes. The list of the meeting dates, locations and titles are listed previously in the “Methods” section. The website where the manual and handbook chapter are featured is

The evaluation results of the program are detailed in the “Outcomes and Impacts” section previously mentioned.

Outcomes and impacts:

The primary outcome of the project was the development, publication and distribution of the handbook and CD. The manual is available on line at

A secondary outcome was the publication of a summary article as a chapter in the book “Targeted Grazing: A Natural Approach to Vegetation Management and Landscape Enhancement” by the American Sheep Industry Association. The book is available at

A third outcome was the inclusion of the handbook and book chapter content on two websites targeting individuals interested in using livestock grazing as a weed management tool. The websites were: and

The impacts were measured using a mail survey as previously described. The results indicate the manual was utilized by individuals in all the targeted states. Table 1 presents the number of valid survey responses by state.
The primary target audience of the WSARE program is CE and NRCS employees. The response to the survey indicates that the majority of the individuals using the manual were employed by these organizations. Table 2 presents the number of valid evaluation survey responses by employer.

The survey respondents provided information about several important impacts related to of the handbook. Due to the large sample size and robust return rate, the survey results were considered representative of the entire population of individuals who received the handbook.

The results indicate that the manual is being used on a regular basis by the recipients, with 95 percent of the users reporting it as somewhat to very useful, and 92 percent of the users reporting increased knowledge and awareness of the subject. Approximately 98 percent of the users reported that they consider the information in the manual to be accurate to very accurate. The information in the manual was shared with others by 61 percent of the users, while 20 percent cited it, 12 percent used it to design a grazing system for noxious weeds, and eight percent used it to teach a workshop. Nearly 80 percent indicated that their willingness to prescribe livestock grazing for noxious weed control had increased as a result of using the manual. Slightly less than 30 percent of the users reported implementing grazing prescriptions described in the publication. Nearly all the respondents (93 percent) requested additional publications on the use of livestock as an environmental management tool. When asked how the publication could be improved, less than six percent of the respondents suggested any improvements were needed

The following questions and responses are taken from the evaluation instrument.

1) How often do you refer to or use the publication “Livestock Grazing Guidelines for Controlling Noxious weeds in the United States”?
a) Never 24%
b) Sometimes 70%
c) Often 6%

2) Did the publication increase your knowledge and awareness concerning the use of livestock grazing to control noxious weeds?
a) Not at all 8%
b) Somewhat 66%
c) A great deal 26%

3) How useful did you find this publication?
a) Not useful 5%
b) Somewhat useful 59%
c) Very useful 36%

4) How have you used it?
a) Cited it 20%
b) Conduct a workshop 8%
c) Designed a grazing prescription 12%
d) Shared information with others 61%

5) Has this publication increased your willingness to prescribe livestock grazing as a noxious weed control technique?
a) Yes 77%
b) No 23%

6) Have you implemented any grazing prescriptions presented in the publication to control noxious weeds?
a) Yes 27%
b) No 73%

7) How accurate do you consider the information presented in the publication?
a) Not very 2%
b) Accurate 80%
c) Very accurate 18%

8) Would you like to see other publications written that address the use of livestock as an environmental tool?
a) Yes 93%
b) No 7%

9) What could be done to improve the publication?
a) Layout/design .6%
b) Content/scope 6%
c) Graphics 2%
d) Readability 2%
e) Usefulness 2%

Based on the widespread sharing of the manual and the reported willingness to apply livestock as a management tool, the authors expect increased use of livestock grazing to control noxious weeds.

Project Outcomes

Project outcomes:

The primary accomplishments are increased levels of awareness and knowledge of livestock grazing as an environmental tool in several western states. The handbook also presented “state of the art” information concerning the use of livestock as a weed management tool in a single easy to use format that had never been done before. The WSARE program and the handbook, were highlighted before approximately 240 BLM employees during the Integrated Pest Management classes taught six times by the authors. This partnership between BLM and the authors had not occurred before.


Potential Contributions

Approximately 36 percent of the recipients of the manual worked outside of CE or NRCS. They included agricultural producers and other agricultural professionals from a broad range of employers. These individuals were included in the evaluation survey and indicated significant knowledge gains and increased levels of understanding after using the handbook.

Future Recommendations

The authors strongly recommend the production of additional handbooks featuring the use of livestock grazing as an environmental management tool. This recommendation is supported by the evaluation results which indicated 93 percent of the respondents requested additional publications on this subject. Specifically, the respondents identified the following topics concerning targeted livestock grazing as most needed : reduce wildfire fuel loads; improve wildlife habitat conditions; change species composition on rangelands, restore and/or revegetate natural areas; and multi-species grazing.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.