Using Cattle to Rehabilitate Rangeland Vegetation and Improve Ecosystem Function (3 yr project)

Project Overview

Project Type: Professional + Producer
Funds awarded in 2010: $49,936.00
Projected End Date: 12/31/2013
Region: Western
State: Colorado
Principal Investigator:
Kathy Voth
Livestock for Landscapes

Annual Reports


  • Additional Plants: native plants
  • Animals: bovine


  • Animal Production: feed/forage, grazing management, pasture renovation, preventive practices, range improvement, grazing - rotational
  • Education and Training: demonstration, farmer to farmer, networking, participatory research, workshop
  • Farm Business Management: feasibility study
  • Natural Resources/Environment: biodiversity, habitat enhancement, soil stabilization, wildlife
  • Pest Management: cultural control
  • Production Systems: agroecosystems
  • Soil Management: soil quality/health
  • Sustainable Communities: local and regional food systems, partnerships, public policy, urban/rural integration


    This three year project was a demonstration to show how or if we can manage cattle to reduce weeds and improve ecosystem function on Western rangelands. Our theory was that by using cattle trained to eat weeds and focusing them on weedy sites we could reduce weeds, improve soils, and increase the potential for native and grass species to return.

    PDF Version of This Report

    The attached PDF includes photos.


    "Plans get you into things, but you've got to work your way out." Will Rogers

    This quote from Will Rogers is the best description of the course of this project. When I prepared the proposal, I thought that three years was enough time to gather the information I thought I needed. I didn’t factor in extreme fluctuations in precipitation from cool temperatures and record rainfall in one year to a stock pond-emptying drought in the next. I also could not have anticipated that my project pasture would become the site of herbicide trials, or that a new biking and hiking trail would be built through the pasture with a trailhead parking lot constructed on a portion of my first trial pastures. Having spent almost 15 years building electric fence for both goats and cattle, I never imagined that this project would test my skills and knowledge beyond their limits. I especially did not plan for the hikers and bikers and herbicide researchers who would turn off the electric fence and let the cattle out. When endangered leopard frogs were discovered in the primary water source for the cattle grazing in the pasture during the second season of the project, it was just one more challenge in a series.

    "Everyone has a plan until they get punched in the face." Mike Tyson

    As these unforeseen circumstances came up, my assistant and I worked with the ranchers and our Boulder County partners to adjust grazing timing and location, cattle numbers and fence lines. The kinds of changes we made were always designed to help us meet our goal of demonstrating how or if cattle could be intensively managed in a a landscape to reduce weeds and improve ecosystem function.

    Lessons Learned

    Though we weren’t always grateful for the learning opportunities presented to us, we did learn a lot. I list the key points here and discuss them in greater detail later.

    1. Electric fencing in arid climates is a special challenge that is not easy to overcome.

    2. Mob Grazing presents significant challenges beyond simply managing the animals. Some were logistical, some were political, some were a result of how grazing has been managed in this area both historically and currently, and some were a combination of all three.

    3. Cattle will focus on weeds on their own, and changes in weed populations can and do occur.

    4. Change is hard.

    Project Background

    In spite of continued efforts to control invasive species and the best efforts of herbicide companies to develop products for their management, weeds continue to spread nationwide at an average rate of 14% per year. In 2000, farmers and ranchers were already spending $5 billion to control pasture weeds, and an additional $1 billion was lost due to reduced grazing potential, reduced wildlife-related recreation, higher levels of soil erosion and reduced water quality (Pimental et al 2000). Researchers Rejmanek and Pitcairn noted in 2004 that when a weed is wide-spread “biological controls may be the only long-term effective way to suppress its abundance over the invaded area.”

    Managing weeds on rangelands in the arid west is difficult because weedy species are spread over many acres, increasing the cost and difficulty of using herbicides, fire and mechanical controls. In addition, herbicides may be doing more damage than good to our forage base. The title of the sixteen year study by Rinella et al summarizes his findings succinctly: “Control effort exacerbates invasive-species.” The paper concludes that, “Aside from a transient increase in grass forage production, herbicide provided little benefit to the livestock producer or the ecosystem we studied. One of the primary objectives of spraying was to increase cattle forage by decreasing Euphorbia esula (leafy spurge) production, but paradoxically, two sources of evidence suggest that herbicide ultimately increased E. esula production.” They note that their previous research showed that grasses and forbs compete with E. esula, and as herbicide leads to long-term suppression of several native forbs, it followed that reduced native-forb abundances would lead to increased production of the target weed. Thus, spraying was actually increasing their problem. Research by Fuhlendorf et al (2009) supported Rinella’s conclusions that herbicide did little for the producer’s forage base or bottom line. While forbs were reduced by herbicide, grass cover varied more due to annual precipitation than herbicide treatments and “...livestock production was not altered either on an individual basis (gain/head) or on an area basis (gain/ha).”

    Both research and experience have demonstrated that grazing can be used to reduce weed populations when timing and intensity of grazing is managed to put stress on target plants. As the graph indicates, a plant’s palatability and susceptibility to grazing changes over the growing season, with both decreasing after seed set (Launchbaugh 2006). Since palatability is based on the nutritional value, it is obvious that we will have best luck with grazing when the plant’s nutritional value is higher. Since seeds may also be spread in the manure of grazing animals, it also makes sense that we avoid grazing after seed set. Thus by paying attention to the growth stage of the target weed, we can pick a time before seed set to graze for maximum impact.(See Plant Palatability Graph)

    Can Cows Eat Weeds?

    In 2004, I began working on a process to turn weeds into forage for cattle. The inspiration came from work done by Dr. Fred Provenza and his colleagues at Utah State University that described how animals choose what to eat. They found that animals learn first from their mothers what to eat, and then from internal feedback from nutrients and toxins in foods (Provenza 2003). My theory was that animals did not eat weeds because their mothers had not eaten them, but that if they were nutritious, and if I could get them to take a bite of a weed, they would experience good feedback and would learn to eat the weed in pasture.

    I tested this theory in a pilot project at Grant-Kohrs Ranch National Historic Site in Deer Lodge, Montana. I have since refined the process so that anyone can teach a cow to eat a weed in just eight hours over seven days. Because weeds are generally as good or better than alfalfa in nutritional value (Voth, Livestock for Landscapes website), cattle will eat weeds in pasture and remember them year after year. By teaching cows to eat weeds, producers have more forage available and they reduce costs for weed management. Cows teach their herd mates and calves to include weeds in their diets and they continue eating weeds year after year, even adding new weeds on their own. For more on the training process visit

    In 2007 and 2008 I used this process to train Babe and Leo Hogan’s cows to eat late-season diffuse knapweed and Dalmatian toadflax. In 2009 we moved these trained cows and their calves to the Mayhoffer pasture with 30 cow-calf pairs belonging to Bill Hogan. We wanted to watch as the trained cows taught the untrained cows to eat weeds.

    The weeds the cows ate exceeded our expectations. They ate very little grass and preferred to graze in the weedy area created by prairie dogs on the south end of Mayhoffer (Voth 2009). Based on what we saw, we theorized that by managing them more intensively we could reduce weeds and increase grasses and native forages. Thus we developed and submitted a proposal for a demonstration project to Western Sustainable Agriculture Research and Education (Western SARE) to further explore this possibility.

    We selected the Mayhoffer pasture for this demonstration because it had a significant invasive species problem and it was also easy for participating ranchers to move cattle into and out of. Before Boulder County acquired this property as part of its open space program, it was continuously grazed. Ranchers remember it as having some of the best forage in the area. However county managers were concerned that the big bluestem populations were decreasing as a result of grazing, and under their management 38 of Bill Hogan’s cow-calf pairs graze it for two to three weeks annually. Weed invasions in the pasture are quite large and include a growing population of diffuse knapweed, Dalmatian toadflax, tumble mustard, curlycup gumweed, broom snakeweed, horehound, wormwood sagewort, a variety of thistles and more. Weed invasions and soil erosion are being enhanced by a 200 acre prairie dog colony on the southern slope of the 500 acre pasture and on the upland portion where prairie dogs were once reintroduced. (See Mayhoffer Map)

    Because educated cattle were readily eating weeds in this pasture, we wondered if focusing them on portions of the pasture using Mob Grazing techniques might lead to improvements. As enthusiast and mob grazing expert Greg Judy explains, pastures are stocked at the equivalent of 1600 head per acre (the mob), and animals are moved when they have "eaten half and trampled half." The purpose of this level of impact is to increase soil organic matter and nutrient cycling and improve the water cycle by incorporating plant material into the soil surface and improving it with manure and urine. Practitioners, including University of Nebraska Extension Specialist Terry Gompert, say that mob-grazed pastures show an increase in soil-organic matter of 450% in just a few years, as well as increases of up to 200% in native and forage species production.

    We expected numerous challenges in exploring mob grazing in this area. Given that arid regions in the west do not typically have the same amount of biomass available for grazing or trampling, it seemed unlikely that gains could be achieved at the scale described by Gompert. We wanted to see what kind of changes we could expect. Another issue was that as currently managed mob grazing systems require intensive management of animals, with some operators moving cattle twice a day or more. This was the opposite of traditional management in the area where producers run a series of smaller herds of cattle on scattered pastures, grazing them season-long. It was the hope of our Boulder County partner that this project might demonstrate how herds could be combined on larger pastures to increase stocking density without increasing labor. With that in mind, we hoped to develop examples of the kinds of stock densities that would work best in more arid regions and how they affect forage and livestock productivity.

    The basics of the three year proposal funded by Western SARE included:

    • Working with weed-eating trained cattle belonging to Babe and Leo Hogan and Bill Hogan on the Mayhoffer pasture managed by Boulder County Parks and Open Space.

    • Sharing information and gathering input from ranchers and the City of Boulder open space managers so that whatever grazing management we developed would work for them and others as well.

    • Doing rangeland health assessments, repeat photo monitoring and other data gathering to determine if our management is having the results we hope for.


    Fuhlendorf, S.D., D.M. Engle, C.M. O’Meilia, J.R. Weir, D.C. Cummings. 2009. Does herbicide weed control increase livestock production on non-equilibrium rangeland? Agriculture, Ecosystems and Environment. Volume 132: Issues 1-2, July 2009.

    Launchbaugh, K.L. 2006. Targeted Grazing: A Natural approach to Vegetation Management and Landscape Enhancement. An American Sheep Institute Publication. Available online at:

    Pimentel David, Lori Lach, Rodolfo Zuniga, and Doug Morrison. 2000. “Environmental and Economic Costs of Non- indigenous Species in the U.S.” Bioscience 50, no. 1. p. 53-65.

    Provenza, F.D., 2003. Foraging Behavior: Managing to Survive in a World of Change. Department of Forest Range and Wildlife Resources. Utah State University.

    Rejmnek, M., and M. J. Pitcairn, in Vietch, C.R. and Clout, M.N. (eds). Turning the tide: the eradication of invasive species, 2004. IUCN SSC Invasive Species Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

    Rinella, M.J., B.D. Maxwell, P.K. Fay, T. Weaver and R.L. Sheley. 2009. Control effort exacerbates invasive-species problem. Ecological Applications. 19(1), 2009, pp. 155-162.

    Voth, K. 2009, GLCI 2009 Final Report:
    Voth, K. Livestock for Landscapes web site:

    Project Participants

    Our primary partners in this project were Boulder County Parks and Open Space, Rob Alexander and Meaghan Huffman and the ranchers who supplied the cattle, Albert (Babe) and Leo Hogan and Bill Hogan. Brothers Babe and Leo owned the first cattle to be trained in Boulder County and their cousin Bill was the Mayhoffer pasture lessee. We met with our primary partners to plan for the upcoming season, make adjustments along the way, and then to talk about what went right at the end of the season, and what we would like to do differently.

    The City of Boulder also owns extensive open space, some of which is managed for grazing and is adjacent to grazing lands managed by Boulder County Parks and Open Space. Because of this close relationship, I asked Andy Pelster of Boulder Open Space and Mountain Parks to act in an advisory capacity to the project. We share information and invited him to meet with us on site, and his thoughts about the politics, science and art of grazing management informed some of the lessons learned.

    Initially we also had four ranchers participating in an advisory capacity: Al Green, Dick Miller, John Hall and Jim Roberts. None of them participated in the Rangeland Health Assessment training, nor in the end of the first year review, and since they didn’t return phone calls we understood that they were no longer interested in participating.

    Project objectives:

    Here are the objectives as described in the original proposal. I will describe methods and what happened during the project in the subsection below.

    1. Train City and County staff and participating ranchers in the use of rangeland health assessments to create a team of monitors. Spring 2010

    2. Set up demonstration site pastures and manage cattle within them.

    3. Conduct six rangeland health assessments for each of the demonstration areas over the course of three years. As it turned out, the pasture was in one soil type, so that doing rangeland health assessments over the entire area would not have given different results.

    4. Develop draft criteria for managing high density grazing including number/pounds of animals per acre, how long animals should be in one pasture based on changes in forage. This criteria will be developed using input from participating ranchers, successful practitioners, available literature and adaptive management during the project. Criteria will begin development in the fall of 2010 and will be completed by the end of the project in 2012.

    5. Create outreach and education materials to share with producers, City and County staff, media, County commissioners, open space advisory boards, NRCS and extension staff and others. These will include results in report form, flyer invitations and handouts for field days, and a video on DVD documenting the project. Results will
    also be available on the Boulder County Parks and Open Space and the Livestock for Landscapes web site. Outreach and education materials will begin development in spring of 2012 and will be completed by the end of the project in 2012. Results will also be shared at annual meetings of producers with County and City staff.

    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.