Targeted grazing is the specialized use of livestock grazing or browsing to achieve landscape management goals. The term, targeted grazing, evolved from the need to clearly label the practice of using livestock grazing, or browsing, for short periods at high intensity to reduce the presence or vigor of pest plants as part of an integrated pest management (IPM) program. This term is also used to refer to the reduction of plant cover to reduce fire risk (Launchbaugh and Walker, 2006).
USDA NRCS (2017) describes the term prescribed grazing in Code 528 as “managing the harvest of vegetation with grazing and/or browsing animals with the intent to achieve specific ecological, economic, and management objectives.”
NRCS considers that this grazing occurs within a Conservation Management System, and requires that the grazing be for specific purpose to improve or maintain:
desired species composition, structure and/or vigor of plant communities
quantity and/or quality of forage for grazing and browsing animals’ health and productivity
surface and/or subsurface water quality and/or quantity
riparian and/or watershed function
reduce soil erosion, and maintain or improve soil health
quantity, quality, or connectivity of food and/or cover available for wildlife
fine fuel loads to achieve desired conditions
The use of prescription grazing within NRCS focuses on landscape goals as well as production practices of livestock enterprises. Thus, prescriptions may covers a longer timescale and be coordinated with production goals within a particular livestock industry.
Components of Targeted Grazing
Targeted grazing differs from grazing systems in which a livestock manager plans for 365 days of forage by balancing pasture and conserved forage resources with the nutritional needs of the herd. In contrast, the focus of targeted grazing is to achieve defined vegetation or landscape goals. The specific components of this management tool include the application of a specific kind of livestock at a site for a(n):
The emphasis is on the vegetation and its response to grazing. If weeds are the target, the timing of the treatment is chosen so that the herd will consume as much of the aboveground portion of the plant as possible. In some situations, such as with Himalayan blackberry, a second treatment in the same year may be advisable. For weed management, repeated treatments are needed. Plants which have become invasive have overcome constraints to growth and are more vigorous than other plants.
It is important to remember that palatability of plants changes during the growing season. Weeds may also be selected by animals when their preferred forage plants are not available. We often allow animals to avoid less palatable plants by moving them, but then undesirable plants increase in density or vigor. Flynn (2019) commented on the prevalence of ragweed and that cattle will eat it early in the growing season when grasses are not actively growing. Over time, however, even a few ragweed plants will go to seed and increase in density in a pasture. Avoiding this situation requires adjusting gazing, treating with herbicide, and managing soils for the growth of desired species. If these opportunities are lost and a less palatable species encroaches, some herdsmen will turn to targeted gazing by a species which selects different plants to improve the pasture sward.
In Figure 1, Walker et al. (2006) illustrate the effect of conversion from sheep and cattle grazing to primarily cattle grazing over an 80-year period in the western United States.
Implementing targeted grazing as part of a management plan
When a site is assessed to be a candidate for targeted gazing, the grazier must clearly understand the goals of the land manager. While targeted grazing will reduce the percent cover or vigor, refered to as weed control, the pest plant will not be eliminated. Eradication is not accomplished with grazing or any other tools unless repeated treatments are applied.
Livestock vs. Herbicides
Herbicides are an alternative for weed control but may not be desirable due to restrictions or public sensitivity about their use. Livestock can access areas that are steep, rocky, or have other hazards that do not allow access by mowing equipment. It is estimated that the cost of managing invasive plants in the United States is $34 billion (Fuller and Mangold, 2017). While targeted grazing may not be the most affordable on a per acre basis, it may have a role depending on site characteristics and the practicality of using mechanical methods (i.e. mowing or grubbing), herbicides, or biocontrols (i.e. insects or fungi selected from the home range of the pest plant).
Soil Conditions Considerations
The timing of targeted gazing must consider soil health. Grazing livestock should not be herded onto a site when the soil is wet and at risk of being pugged by hoof action. The plant species being targeted should be in a vegetative growth stage and palatable to the livestock. Although the pest plant may not be a usual forage for the livestock, training for its consumption is frequently done prior to site treatment.
Many targeted gazing jobs are done in locations that otherwise would not have livestock present. This includes private property at the urban interface, parks, and other public places. In other situations, hiring a species of animals which selects plants other than the ones purposefully raised by a farmer is a helpful tool.
Timing and Plant Development Stage
For some targeted plant species timing is critical. For example, when cheatgrass (Bromus tectorum) is in the reproductive stage, its spikelets have awns and it is not palatable. However, repeated grazing in the vegetative stage will reduce tiller numbers and therefore reduce seed production. In contrast, choice of livestock species is critical for control of leafy spurge (Euphorbia esula); goats or sheep will browse this species but it is not palatable to cattle (Launchbaugh and walker, 2006).
Examples from different ecosystems
In the California annual grasslands, where summer rainfall is scant and severity of drought challenges winter growth, restoration of grasslands is challenging. Because livestock are herded in much of this region, adjusting the timing and intensity of grazing is the most readily available management tool.
Davy and Rinella (2019) reported that gazing tarweed (Hemizonia ﬁtchii) and vinegarweed (Trichostema lanceolatum), both of which are native forbs, may be desirable for pollinators.
The Targeted Grazing handbook is available at: https://targetedgrazing.org/other-resources/. This publication contains information on the principles and practices of using livestock grazing and browsing as a tool for weed management and fire fuels reduction.
Other resources at the Targeted Grazing web page include webinars, scientific papers, and news items.
Contact the Targeted Grazing Committee of the Society for Range Management (https://rangelands.org/committees/targeted-grazing-committee/) for more information about the activities of a group of professionals committed to the scientifically-sound and ecologically based use of this management tool.
Davy, J. S. and M. J. Rinella. 2019. Targeted grazing for native forbs in annual grasslands. Rangeland Ecology and Management 72(3): 501-504.
Flynn, S. 2019. Weed and Brush Control: myths and mistakes. Hay & Forage Grower. April/May, pp. 24-25.
Fuller, K. B. and J. Mangold. 2017. The costs of noxious weeds: What you can do about them. Montana State University Extension. http://www.msuextension.org/magazine/assets/docs/ss2017noxiousweedcosts.pdf
Goehring, B., K. Launchbaugh, and L. Wilson. 2010. Late-season targeted grazing of Yellow Starthistle (Centaurea solstitialis) with goats in Idaho. Invasive Plant Science and Management 3(2): 148-154.
Launchbaugh, L. and J. Walker (eds.) 2006. Targeted Grazing: A natural approach to vegetation management and landscape management. American Sheep Industries Association, Centennial, CO.
USDA NRCS. 2017. Conservation Management Practice- Prescribed Grazing Code 528 (Ac).
https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1255132.pdf (Accessed 27 August 2019.)
USDA NRCS. 2019. Prescribed Grazing. https://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/programs/?cid=nrcs144p2_027164 (Accessed 27 August 2019.)
Walker, J. W., L. Coffey and T. Faller. 2006. Improving grazing land with multi-species grazing. in: Targeted Grazing: A natural approach to vegetation management and landscape management. Launchbaugh, L. and J. Walker (eds.) American Sheep Industries Association, Centennial, CO.