Effectiveness

The effectiveness of prescription grazing by sheep and goats has been clearly demonstrated for the management of leafy spurge, which aggressively competes with native plants on over 3 million acres of rangeland in the Northern Great Plains. According to the Government Accounting Office, these invasions are estimated to cause about $100 million in damage each year (GAO 2001). Because cattle avoid grazing leafy spurge, the forage value of rangeland and pastureland can be decimated as leafy spurge invades and forms near monocultures. Fortunately, sheep and goats readily graze leafy spurge, finding it a nutritious and desirable forage and selecting it before resorting to eating grasses. Sheep and goats are highly effective tools for reducing the dominance of leafy spurge and are a readily applied technique in many areas of Montana and North Dakota (MSU 2002). Using sheep to control leafy spurge can cost as little as 60 cents per acre, compared to a cost of $35 per acre to spray herbicides from a helicopter. Currently, Montana weed trust fund dollars compensate sheep producers $1 a head per month for grazing services to control leafy spurge on over 28,000 acres. Click here for more information on leafy spurge grazing.

Spotted knapweed is considered one of the most troublesome rangeland weeds in the northern United States and Canada. It is an aggressively spreading weed currently occupying more than 7.5 million acres of Western rangelands and costing the livestock industry more than $42 million a year in lost forage and in additional weed control expenses. Herbicides, insects, pathogens, and fires have not effectively contained the spread of this noxious weed. Sheep readily graze spotted knapweed, consequently reducing its reproductive output and abundance. Click here for more information on spotted knapweed grazing.

In the Southeastern United States, the aggressive climbing vine kudzu is rapidly spreading, overtaking everything in its path. Over 7 million acres are dominated by kudzu, and it is spreading at a rate of about 120,000 acres a year. This plant can easily creep up trees, fences, power poles, machinery, and buildings. Its aggressive growth costs the forest industry over $20 million every year in Mississippi alone. Sheep and goats readily browse the leaves and young stems of this massive plant, providing an alternative to costly traditional control strategies based on herbicides and mechanical removal. After several years of grazing, kudzu can be radically reduced in stature and basically kept in check. Click here for more information on kudzu grazing.

There is growing interest in livestock grazing to reduce fire fuel loads in response to continued urban development at wildland interfaces and to the extensive and destructive fires of 2000. Strategically applied sheep and goat grazing has reduced the risk and extent of wildfire in many settings. The most successful programs to reduce fuel loads are in California, where goats and sheep are commonly employed to graze the highly flammable shrubs of the chaparral region. Intensive grazing at the urban interface can create effective firebreaks as was accomplished near Carson City, Nevada, in a program named “Only Ewes Can Prevent Wildfire.” A fenced corridor around the city was grazed by ewes resulting in removal of 71 to 83% of fine fuels. A survey of nearby homeowners revealed that over 90% supported the project and preferred the sheep to traditional chemical or mechanical methods of creating fuel breaks. In the Great Basin, extensive wildfires often burn through areas dominated by cheatgrass. Intense sheep grazing of cheatgrass-dominated sites, for as little as two years, can effectively suppress or even eliminate cheatgrass stands (Mosley 1996). Though targeted grazing is used minimally for fuel management on federal forest rangeland, success has been demonstrated by several trial projects, and opportunities for targeted grazing are expected to expand. Federal funds for hazardous fuel reduction, exceeding $350 million a year, could be used to secure the services of sheep and goat operators.