The herd of 17 goats was all business.

The animals, white with patches of bronze, black and mahogany brown, meandered along in a west metro pasture this week, chomping away at buckthorn and prickly ash, leaving in their path groupings of scraggly sticks.

Their buffet of roughage is part of an experiment to get rid of unwanted invasive plants and weeds without herbicides.

"The idea is to keep grazing and keep grazing and get those roots to burn their energy out," said Tim Reese, farm operations supervisor at Gale Woods Farm in Minnetrista, where the goats were grazing. "If we can do this on a small scale, then maybe we'll be able to replicate it elsewhere."

The working farm, part of the Three Rivers Park District, provides outdoor learning for daily visitors, summer camp students and school groups.

It was Reese's idea to try the goats as an experiment on 4.5 acres of the farm that he wants to return to its native state — diverse grasses for pasture intermixed with huge oak trees. Previous attempts to cut the persistent weeds and paint their stalks with herbicides have been expensive, temporary and not particularly good for the environment, he said, so goats were worth a try.

"They're browsers, so they'll go after the leaves on shrubby things before they'll actually eat the grass that's on the ground, so this is the right kind of forage for them to eat," Reese said.

The animals, a relatively recent breed called Kiko goats, aren't the tame variety that cozy up to children at petting zoos. They're twice as large and skittish around people and they stick close together. The buck of the herd, the only one with a name — Mephisto — is a 200-pounder more than twice the size of the others.

On a recent morning in their field, some reared up on their hind legs to reach higher leaves, and a few rested on an immense downed tree stump, digesting their food and overlooking the site. They have nearly denuded the first of the 4 acres in the past two weeks and will soon be rotated to the next section for additional feasting.

But not all is restful for the goats. They're surrounded by an electrified portable fence to keep them from straying, and they're joined by a pair of Great Pyrenees guard dogs at night to keep away coyotes.

Win-win arrangement

Will Winter, who owns the goats, has two other herds clearing invasive plants, one on a small farm near Winona and another in Wisconsin, and has a waiting list of other sites that people want cleared.

Winter, who also works as a herd health consultant for Thousand Hills Cattle Company, takes his animals ­personally.

"Goats live on what nobody else wants," he said. "So they're kind of like my role model."

Winter said goats are the ideal solution to provide constant pressure against stubborn weeds such as buckthorn.

"When the goats have had their way with it, then you can come in with your luxurious cattle that are kind of elite like poodles and only want to eat that green, soft grass," he said.

The arrangement with Three Rivers involves no money, he said. The goats get fresh feed, and the farm gets free removal of weeds.

Winter cautioned that the goats prefer shrubs, but once the leaves are gone, they'll start eating grass and everything else.

"That's just what they do," he said. "We don't know where they put it all. We don't know where it all goes."

Repeat performance

Reese said the use of goats to control buckthorn, garlic mustard and other pesky weeds is rare in the Midwest as far as he knows, but they've been used for years in the Southeast to control the invasive kudzu vine, and in Montana and other Great Plains states to beat back the spread of leafy spurge on rangelands.

Even after the goats graze the park's farmland a couple of times this year, Reese expects he may need to bring them back for a second year, because buckthorn grows back quickly from its roots and also spreads by seed.

He also is planning a secondary assault on the buckthorn with another strategy: pigs.

"Pigs will root it up and eat some of those buckthorn roots so we can move in and get some grasses planted," he said.

Tom Meersman • 612-673-7388