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Use Target Grazing To Take Aim At Invasive Weeds

Article-Use Target Grazing To Take Aim At Invasive Weeds

Targeted grazing can be highly effective to improve pasture quality without pesticides.

There's a new buzzword out West when it comes to grazing --targeted grazing.

Karen Launchbaugh, chair of the University of Idaho's Rangeland Ecology Department, defines the term as "using grazing in a new way that offers an ecologically friendly aspect to accomplish defined vegetation goals."

Think of it as turning a butter knife into a scalpel, Launchbaugh says. "Targeted grazing is transforming grazing into something that can really be directed on the landscape." It includes utilizing livestock grazing to:

  • reduce weeds in crop systems, rangelands and forests,
  • control herbaceous biomass in tree crops,
  • reduce fire fuel loads,
  • help manage watershed characteristics,
  • improve wildlife habitat and
  • help restore wildlands.

Of those, the fastest growing target grazing example is the use of livestock -- particularly sheep and goats -- as a means to manage weeds.

"Targeted grazing can be highly effective to improve pasture quality without pesticides... and we're converting weeds into saleable product," Launchbaugh says. She adds that it's environmentally friendly, a sustainable form of weed control, and often more feasible.

Numerous producers are using sheep and goats to successfully graze leafy spurge, cheatgrass, juniper and other weedy species, she says. But new research training cows to eat specific weeds is also showing promise.

Kathy Voth, a land management researcher and consultant, has conducted trials in Montana and California teaching cattle to eat everything from leafy spurge and spotted knapweed to Italian thistle. With a little training, she says it's possible to get cattle to eat just about any type of forage. (For more on Voth's methods, read the May 2005 BEEF article, "Weed Whackers," at

John Walker, director of the Texas A&M Agricultural Research and Extension Center at San Angelo, believes these weed management success stories are just the beginning. "Weeds are here to stay, and we need to learn to manage them. Weeds are often nutritious and can be a feed source. Livestock producers just need to think differently," he says.

"Thinking differently" is the first step in applying targeted grazing principles. Launchbaugh and Walker explain that practitioners of this strategy need to shift their focus from meat and livestock products to managing plant communities.

The two key principles to targeted grazing include the type of animal and timing of grazing.

The first principle -- type of animal -- requires land managers to evaluate the kind of livestock they're grazing and determine which may be best suited to the vegetation challenge they're trying to address.

"Kind of livestock" is the most important element for controlling invasive species with targeted grazing, Walker says. Different types of livestock have certain preferences -- cattle prefer grass, sheep select forbs, and goats prefer shrubs. Likewise, sheep and goats can better tolerate steep slopes for grazing compared to cattle.

Thus, in order to control weeds and brush on rangelands, these lands must be grazed by animals that prefer forbs and shrubs. To his point, he relates how sheep numbers have decreased over the past decade while weeds have taken over millions of acres -- Walker believes there's some correlation.

Walker acknowledges many ranchers don't want to raise sheep, but he believes it's necessary to get weed infestations under control in the U.S.

"Weeds are the greatest biological disaster the country is experiencing. Back in the Dust Bowl of the '30s, the Soil Conservation Service was created to stop erosion and change the way we managed the land. We need to make a change again," he says, of the need for more sheep and goats on grazing lands.

He adds, "In my mind, we've ignored the fact that multiple classes of livestock can make a difference in managing rangelands."

Along with the species of animal, age and experience of the animal can also be tweaked to get them to graze specific plants, Launchbaugh says.

For instance, if livestock are exposed to range plants at a young age, they're more apt to try a variety of plants. Research also shows that animals learn which plants to eat from their mothers and peers. Thus, Launchbaugh says if you have a herd with a few animals that have been trained to eat a certain weed or shrub, they'll likely train the rest of the herd.

Regarding timing, Launchbaugh says grazing must be matched to the time when the weeds or brush you seek to control are most susceptible to grazing while still offering some palatability to animals. For many weeds, this is usually at flowering or seed set; it's more difficult to kill the plant after seed is set.

She explains that because many weeds are early maturing, they've already set seed before many pastures are grazed, which has allowed them to survive and thrive. Thus, changing the timing of grazing, and confining animals to a specific area, to help knock weeds back can be a useful "targeted" grazing tactic.

Launchbaugh and Walker believe targeted grazing is a powerful tool for managing landscapes in the years ahead -- especially in the restoration and rehabilitation of lands.

But Launchbaugh cautions that applying targeted grazing is part art and part science. She says land managers need to understand the target and the goal.

Without the proper knowledge, there's the risk that non-target species can be damaged. Moreover, there can be costs associated with targeted grazing, such as fencing, water, herders and possibly reduced animal production, but she adds, "These concerns are manageable."

Additionally, Launchbaugh points out that land management through grazing is an ongoing process. "This has a long time frame and always requires some maintenance. But it's not just about weeds. It's about the long-term sustainability of the land," she says.

A new handbook on targeted grazing as a tool for weed management is now available. In 18 chapters, it provides a compilation of the latest research on targeted grazing of vegetation to improve the function and appearance of a wide variety of landscapes. Created through funding from the National Sheep Industry Association and the American Sheep Industry Association (ASI), it's available online at Printed copies also are available through ASI ([email protected]) for $25.
-- Kindra Gordon for the Grazing Lands Conservation Initiative (

TAGS: Livestock