Implementing Noxious Weed Control Through Multi-Species Grazing

2006 Annual Report for SW03-006

Project Type: Research and Education
Funds awarded in 2003: $187,935.00
Projected End Date: 12/31/2007
Matching Federal Funds: $187,935.00
Region: Western
State: Washington
Principal Investigator:
Dr. Donald D. Nelson
Washington State University

Implementing Noxious Weed Control Through Multi-Species Grazing


A partnership including private landowners, a contract sheep and goat grazier, Washington State University Extension, USDA/ARS, Washington Department of Fish and Wildlife and the Big Bend Resource Conservation and Development Council have joined forces to investigate the use of multi-species grazing as a tool, in combination with herbicides, mechanical clipping and/or tillage, in the control of noxious weed infestations. Grazing combinations of cattle, sheep and goats will be evaluated as a tool in an integrated pest management strategy in the control of invasive plants. Two field sites have been selected in Eastern Washington to monitor treatment impact over three grazing seasons (2004-2006).

Objectives/Performance Targets

Objectives/performance targets as listed in proposal

Management Support Group (MSG):
One MSG group made up of 6-12 participants and livestock owners involved in the SARE/PDP, Noxious Weed Control Through Multi-Species Grazing and other cooperators will be formed by January 1, 2003.

Holistic system:
Develop a holistic systems approach on two ranch units, involving 2,600 acres, to address the control of invasive plants and noxious weeds, including Russian olive, Scotch thistle, perennial pepper-weed and knapweed species. This system will evaluate weed management effectiveness and long-term sustainability of control and it will outline a process that is economically, environmentally and socially sound.

Overall effectiveness:
Compare overall effectiveness of the holistic system to an herbicide only system.

Information dispersal:
Provide information to producers and the community to improve their ability to formulate land management decisions based on sustainability of the weed control methods.

Producer involvement in studies:
Involve 10 additional producers in designing and implementing studies to insure the information meets the needs of producers and is transferred to a larger audience.

Hands-on teaching:
Provide participants with a deeper understanding of the concepts of multi-species grazing by teaching what they have learned to the public and their peers at 3 tours held one per year beginning in 2005.

Enterprise evaluation:
Evaluate the feasibility of adding additional enterprises such as hair sheep, cashmere fiber-producing goats and meat goats.

Forage quality:
Determine if forage quality is adequate to meet animal nutritional needs at various stages of plant growth and biological stages of the livestock species used.

Livestock management:
Evaluate the effectiveness of each livestock species in utilizing each noxious weed species. Determine the most appropriate livestock species to be used at different stages of growth for each noxious weed. Gain knowledge of when, how much and how often to graze the animals to have the maximum impact on the weeds with minimum impact on the desirable species.

Secondary compounds:
Determine if there are any secondary compounds that may inhibit the utilization of the noxious weeds, as well as the impact on soils and plant germination.

Professional publications:
Publish information and results of the study in 2 professional journals and 2 regional media publications.


Management Support Groups (MSG):
During 2006, some changes in the membership of the Management Support Group took place. Amy Hummer completed her M.S. degree fieldwork commitment in May 2006 and was replaced with Len Zeoli, a Ph.D. student on a time-slip basis. Michael Carpinelli, Jim Dobrowolski and Skip Stonesifer accepted new positions and relocated.

Enterprise evaluation:
The main focus of the Healing Hooves, LLC operation has been on using goats and sheep as a tool for vegetation management. At this point in time the vegetation management enterprise has the greatest profit potential. As the vegetation management business developed more work came available in Western Washington. In western Washington, one of the main weedy plants is Himalayan blackberry. Goats are the best choice for working on blackberries. Healing Hooves is a small family business that has limited labor and land available to manage animals at home during the grazing season. Since the hair sheep could not be taken to western Washington to work on blackberries, most of them were sold with the exception of a few head used to manage the vegetation around home.

The cashmere goats are still in the herd. They are not sheared, as the cashmere hair is not worth much unless it processed and sold as yarn. The cashmere hair enterprise would take a fair amount of time to develop, especially when a person does not spin his/her own fiber. Healing Hooves does not have the time, or the interest, to pursue this enterprise. The cashmere does are still in the herd and are being crossed with Boer bucks. The cashmere (Spanish) goats seem to be better adapted to adverse weather conditions than the Boer goats and have good mothering instincts. By crossing with the Boer bucks, the resulting offspring is a more muscular built animal that results in a better price when selling as a meat animal.

A portion of the herd has to be sold every year due to labor and land constraints. The goats are sold as pets, breeding animals and for weed control projects and meat. The price for a commercial doeling ranges from $100-$150 depending on breed. Meat price for a 60-80 pound wether is around $1.10 per pound, if it has the stockier built Boer frame.

Forage quality:
At the Barker Ranch, pre- and post-grazing clippings in the treatment plots were done. Data on (1) density, biomass and cover of all non-woody broadleaf species, (2) cover of all grass species and (3) density, cover and twig and foliar biomass of Russian olive, (4) before and after grazing clipping results, will be analyzed and reported in 2007.

Livestock management(without tables):
The above numbers were calculated by multiplying the pounds of goats in each plot by the number of days the goats where in each plot. The number provides a way to compare how the carrying capacity of the goats changed from 2004 to 2006. By looking at the change in carrying capacity of the goats during the 1st and 2nd treatments over the three years of the project, some generalizations can be made about the treatments. Comparing the carrying capacity during the 1st treatment across the three years, the carrying capacity increased by about 20% from 2004 to 2005 and there was less than a one percent increase from 2005 to 2006. The increase in carrying capacity from 2004 to 2005 is probably due mainly to the Russian olive re-sprouting after it was stressed by the browsing and bark removal by the goats. That there was no increase in year three during the 1st treatment may indicate that the goat browsing was having an impact on the ability of the Russian olive to re-grow.

The significant decrease in carrying capacity during the 2nd treatment (25% from 2004 to 2005, 42.5% from 2004 to 2006) may indicate that the goat browsing is having a significant impact on the ability of the Russian olive to re-grow after the 1st treatment. If this trend continued, the goat carrying capacity during the 1st treatment would begin to decline as well. A three-year study is the minimum number of years to begin to see changes in a plant community.

In three years, the goats were able to reduce the height of the Russian olive plants and to keep the stands more open that allowed for increased forage production for the cattle. The goats also developed a preference for the Russian olive. Russian olive is good forage for the goats as shown in the nutritional analysis and that the does with kids maintained body condition during the study.

Cow treatments – comparing the changes in carrying capacity of the cows over the three years of the project. The numbers are calculated by multiplying the number of cows by the number of days the cows were in the plots.

The cow carrying capacity during the 1st treatment from 2004 to 2005 increased by over 230% and from 2004 to 2006 the increase was over 470%. There are a number of factors contributing to this increase: 1) increased spring rainfall, 2) removal of old plant material from the tall wheatgrass improving plant vigor and palatability, 3) improved nutrient cycling (i.e., increase in nutrients from manure and breakdown of the increased litter on the ground), and 4) the reduction in over-story canopy of the Russian olive due to goat browsing. The cow carrying capacity during the 2nd treatment declined in 2005 and 2006. The decline could be due to a number of reasons: 1) the 1st treatment in 2004 and 2005 grazing ended on July 14 and 15 respectively and in 2006 grazing did not end until August 1. With the later end date of grazing in 2006 there is a good chance there was less moisture available for re-growth, and 2) the percent utilization in 2005 and 2006 was higher during the 1st treatments than in 2004. The old plant material in the tall wheatgrass plants was mostly removed in 2004, and that increased the palatability of the tall wheatgrass in the subsequent years, resulting in increased utilization.

Barker Ranch bulrush sites:
During 2006, the goat grazing on the bulrush areas was similar to what it had been in 2005. In July, the goats did a good job of removing new growth, but the plants re-grew to 4-5 feet tall before the end of the summer. The goats were not able to go graze these plots later in the season because the area was flooded due to irrigation, so the removal trials were basically ineffective.

In 2006, the cumulative effect of the previous two years combined use of multi-species grazing and mechanical control on the bulrush site was evident. In 2004, the goats were used to graze a very large patch of “old growth” bulrushes. Their grazing activity opened up this patch enough to allow the cattle access so that they could graze more of the biomass. This allowed the area to dry out enough so that the remaining biomass could be mowed with a tractor. In 2005, cattle grazing was effective enough in eliminating the new bulrush shoots that the goats were not needed. The area was mowed again in September 2005 to eliminate the bulrush stems from the wetland.

In 2006, cattle grazing was effective in removing essentially all of the bulrushes from the wetland to the point that it wasn’t necessary to mow the area with a tractor mower. This is good for a waterfowl management standpoint for two reasons: 1) the expense of tractor use, fuel, labor, etc. for mowing the wetland did not have to be spent, and 2) the debris from mowing the thick bulrush stand wasn’t floating in the pond during the winter flooding making it less attractive to waterfowl species. The duck harvest in this wetland is up 138% in 2006 compared to 2003 when the dense stands of bulrush were still present. In comparison, the total duck harvest on the Barker Ranch is only up 13% during the same time period. Another comparison is that in 2003, this area contributed 9.1% of the total birds harvested, but in 2006, it contributed 19.1% of the total birds harvested on Barker Ranch. This shows that the waterfowl species prefer this area with the bulrushes and debris removed compared to those areas with dense bulrush stands. Even though goats have not grazed this area for two years, we believe that we would not have been able to initially remove the bulrushes without the help of the goats grazing them in 2004 to get this process started.

In 2006, the goats were put on another area with bulrush, but the treatment was not as effective as the one in 2004 because of a difficult to control irrigation water level. The goats did not like going into water deeper than 6-8 inches and, in some areas, the water was over 12 inches deep. The deep water also made it difficult to fence the bulrush site into smaller pens to force the goats to graze the bulrush. The water level control is critical to the successful use of goats and cattle on the bulrush.

Sprague Lake learning site (without tables):
When comparing the photos from the three years of the project, some general observations can be made about the impacts of the goats on various weeds at the Sprague Lake site.

Canada thistle: Some Canada thistle went to seed in the goat treated plot in 2004. In 2005 and 2006 none of the Canada thistle plants went to seed. There are still Canada thistle plants within the goat treated plot in 2006. In order to prevent the Canada thistle from reoccupying the site to the level prior to goat grazing, the goat treatments would have to continue on a maintenance basis.

Dalmatian Toadflax: The amount of Dalmatian Toadflax decreased on the areas grazed by the goats. The drier sites appear to have the greatest reduction of toadflax over the 3-year project. During a site visit in late October 2006, several toadflax plants had sent out vegetative growth from the base of the plant since the last treatment in late July. A third treatment late in the fall may be needed on the deep soil sites to increase the stress on the toadflax.

Diffuse Knapweed: The size of the diffuse knapweed plants decreased over the 3-year project. The two treatments per year appear to be adequate to prevent the knapweed from going to seed. The challenge with the knapweed is the soil seed bank where the seed can remain viable for over eight years.

The goats were able to reduce the amount of noxious weeds on the Sprague Lake site. The best way to use goats is as a means to convert a noxious weed problem into a source of income. The noxious weeds are a good source of forage for goats and a goat enterprise can be added to an existing cattle operation without affecting the cattle carrying capacity. There are challenges associated with adding a goat enterprise such as inadequate fencing, predator problems, increased labor for management and learning about marketing goats.

Literature review: Plant physical and chemical defenses
According to Katz and Shafroth (2003), physical and chemical defense mechanisms of mature Russian olive include thorny branches and defense-compound containing leaves. Mature Russian olive can increase thorn density if the tree is cut back (Zouhar 2005). Studies on the effect of plant spinescence on large herbivores found that the main function of thorns and spines was not to eliminate herbivory, but to restrict the bite size of browsing ungulates thereby increasing handling time (Owen-Smith and Novellie 1982; Cooper and Owen-Smith 1986). Unless coupled with small leaves to significantly increase handling time, spines themselves were not effective in deterring goats in a study by Cooper and Own-Smith (1986). They found the strategy of spiney species was to reduce the amount of leaf and shoot tissue losses to herbivores below the level of which they would otherwise sustain (Cooper and Owen-Smith). This was especially important for those species with highly desirable forage (Cooper and Owen-Smith). In their study, Cooper and Owen-Smith (1986) also noted that goats, with their floppy ears, faced an additional problem of catching their ears on the hooked-thorn species, although this did not appear to be a problem in this study.

Secondary metabolites, or compounds, are a plant’s chemical defense against herbivory (Provenza et al. 1994). Cipollini and Levey (1997) define secondary metabolites as compounds found in plants serving no primary purpose, but may be toxic, or at least deter predators, such as herbivores. Even small quantities can hinder growth, cause loss of weight and fur, bring on neurological disorders and even reduce lifespan (Freeland and Janzen 1974). Secondary compounds are not always detectable by animals as they may lack an odor, taste or may even imitate nutrients (Freeland and Janzen 1974). Herbivores are capable of processing secondary compounds, but with limitations. These limitations drive herbivores to be wary of new foods and sample them cautiously and in small quantities at first (Freeland and Janzen 1974). In this study, Russian olive was a new food source for the goats. In the past, the cattle used in this study had access to Russian olive at the Barker Ranch as a potential food source, but had not been fenced in and forced to consider it as forage. Following their initial exposure to Russian olive, the cattle sampled it and continued to sample small quantities on occasion throughout the study, while the goats sampled it and subsequently readily browsed all leaves within reach and also ate the bark off the stems (i.e., girdled them).

In this study, body condition scores of select goats were evaluated before and after feeding on Russian olive leaves and bark. Body condition scores either remained the same or improved, indicating the Russian olive physical and chemical defenses did not adversely affect the physical condition of the goats evaluated.

Literature cited:
Cipollini, M.L., and D.J. Levey. 1997. Secondary metabolites of fleshy vertebrate-dispersed fruits: adaptive hypotheses and implications for seed dispersal. The American Naturalist 150:346-372.

Cooper, S.M., and N. Owen-Smith. 1986. Effect of plant spinescence on large mammalian herbivores. Oecologia 68:446-455.

Freeland, W.J., and D.H. Janzen. 1974. Strategies in herbivory by mammals: the role of plant secondary compounds. The American Naturalist 108:269-289.

Katz, G.L., and P.B. Shafroth. 2003. Biology, ecology, and management of Elaegnus angustifolia (Russian olive) in western North America. Wetlands 23:763-777.

Owen-Smith, N., and P. Novellie. 1982. What should a clever ungulate eat? The American Naturalist 119:151-178.

Provenza, F.D., J.J. Lynch, E.A. Burritt, and C.B. Scott. 1994. How goats learn to distinguish between novel foods that differ in post-ingestive consequences. Journal of Chemical Ecology 20:609-625.

Zouhar, K. 2005. Elaeagnus angustifolia. In:fire effects information system. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Science Laboratory. Available at:

Impacts and Contributions/Outcomes

Summary of Other Activities:
2/15/06: Craig Madsen presented two posters at the 59th Annual Meeting of the Society for Range Management in Vancouver, BC.

5/23/06: SARE Conference, “Sustainable Rural Enterprises,” Ritzville, WA co-sponsored by the Adams County Economic Development, Mid-Columbia Chapter of the Society of Range Management, Big Bend Resource Conservation and Development Council, Washington State University Extension and the Adams County Cattlemen’s Association. The keynote speaker was An Peischel, Tennessee State University Extension Goat and Small Ruminant Specialist, who discussed goat management and grazing behavior in relation to invasive vegetation management, creating niche markets and enterprise development. Forty people attended the conference. (A copy of the conference and tour brochure is attached to this report).

5/24/06: The day following the conference, a SARE Field Tour, Sprague Lake, WA was conducted to look at the vegetation management learning site located at the Washington State Fish and Wildlife boat launch area on the south shore of Sprague Lake. The tour included a review of invasive vegetation management using goats in a wetlands area. Approximately 30 people who attended the previous day’s conference attended this tour.

5/22-29/06: Healing Hooves, LLC arrived at the Sprague Lake learning site for the first grazing treatment on May 22 and left on May 29.

6/22-7/25/06: Healing Hooves, LLC, arrived at the Barker Ranch for the first grazing treatment on June 22 and left on July 25.

7/24/06: Donald D. Nelson visited the Barker Ranch to confer with grazing subcontractor, Craig Madsen, and ranch manager, Michael Crowder, regarding the multi-species grazing project activities.

7/25-30/06: Healing Hooves, LLC returned to the Sprague Lake learning site for the second grazing treatment on July 25 and left on July 30. The Sprague Lake learning site was located along the road leading to a public boat launch. As a result, Craig Madsen answered numerous questions from the general public about the project during the three years.

9/6-22/06: Healing Hooves, LLC returned to the Barker Ranch for the second grazing treatment on September 6 and left on September 22.

10/26/06: Conference call with Andrea Mann, Craig Madsen, Michael Crowder and Donald D. Nelson to discuss project planning.

11/2/06: Craig Madsen made a presentation on this project at the Washington State Weed Association 56th Annual Weed Conference in Yakima, WA. Estimate that 250 people were at the presentation.

Additional project outreach occurred at the Barker Ranch as reported by Michael Crowder, Resident Manager:
1. Wetland Restoration Class from WSU-Tri-Cities campus – Summer ‘06
2. Cattlemen who rent grazing on Barker Ranch and ranch workers – Various times during the project
4. Neighbors of Barker Ranch – Various times during the project
5. Refuge and Wetland Managers – Three times during the project
6. Duck Club owners – Twice during the project
7. Owners of Barker Ranch – Many times during the project

What work is left to do?
1. The data for 2006 need to be summarized and all three years of data need to be evaluated. Amy Hummer is only using two years of data for her M.S. thesis. Someone needs to get all the data together and evaluate it to see how the production of the grasses changed over the three years of the project. Would also like to see a comparison of change in grass production of the grazed plots versus the control plots. Also want to see if there was a significant change in the height of the Russian olive plants over the 3-year project.

2. Analyze and publish results of Barker Ranch experiment in two peer-reviewed journals and two regional media publications.

3. Present project results at professional meetings, industry conferences and local producer meetings.

4. Host regional conference and tour in 2007 (determine the date, topics, speakers and location).

5. Need to coordinate with Barker Ranch for the removal of fence posts that mark plot boundaries and determine if the fence around the plots needs to be removed.

6. Over the three years of the project, unwanted Russian olive trees have been allowed to grow in the study plots. The project still needs to remove all of the Russian olive trees, both dead and alive, in these plots. This will be accomplished by pushing them into piles with a bulldozer and that will probably take 4-5 days. If a burning permit can be obtained, the piles will be burned to remove the debris. Then, the area will need to be mowed with a tractor mower to remove all of the leftover stems and rank grass. During the following months, the Russian olive stems that return will have to be sprayed to kill the roots of the plants that are still alive. It will most likely take two seasons to eliminate the stems that exist in the study area.

Impact and contributions: How does this research, demonstration, training or activity benefit producers or consumers in the Western region?
We hope to be able to demonstrate a method of managing rangelands and wetlands that will positively impact the triple bottom line (i.e., environment, ecosystem and society) by reducing input cost, increasing productivity and enhancing the ecosystem. This includes conversion by ruminants of presently undesirable plant material to marketable products and a reduction in the use of herbicides that decreases both cost and potential environmental hazards to humans, wildlife and natural resources.

We hope to be able to demonstrate a biological method (i.e., planned grazing) that will help control the spread of invasive plants (i.e., noxious weeds), enhance biodiversity and wildlife habitat and increase profit from grazing livestock. This approach will also provide livestock producers with alternative meat and fiber production enterprises to enhance profitability and reduce market risk. An example of one of the existing opportunities is the tremendous undeveloped market potential for goat meat to fill the demand of ethnic groups who eat goat meat as a normal part of their diets.

We also hope to be able to demonstrate that the addition of goats to a beef cattle operation can increase the carrying capacity of the grazing land on which grass, forbs, brush and trees grow without overgrazing. This is attributed to the different grazing preferences of cattle and goats and properly planned grazing that considers length of grazing period, stock density and recovery period between grazing.


Skip Stonesifer

[email protected]
U.S. Fish and Wildlife Service
215 Melody Lane, Rm. 136
Wenatchee, WA 98801
Office Phone: 5096642793
Craig Madsen

[email protected]
Healing Hooves, LLC
P.O. Box 148
Edwall, WA 99008-0148
Office Phone: 5099907132
Michael Crowder

[email protected]
General Manager
Barker Ranch
85305 Snively Rd.
West Richland, WA 99353
Office Phone: 5095213663
Andrea Mann

[email protected]
Big Bend RC & D
2145 Basin St., Suite B
Ephrata, WA 98823-9451
Office Phone: 5097542463
James Dobrowolski

[email protected]
Extension Range Hydrologist
Washington State University
P.O. Box 646410
Pullman, WA 99164-6410
Office Phone: 5093357294
Michael Carpinelli

[email protected]
1041 Mesa Blvd., Suite C
Grants, NM 87020
Office Phone: 5052856963
Amy Hummer

[email protected]
M.S. Graduate Student
WSU/Tri-Cities Campus
1650 Mowry Square #200
Richland, WA 99352
Office Phone: 5095214153