Goat Grazing Controls Weeds

Project Participants:
Sterling Banks, Summit County,
Willoughby Boer Goats, Coalville, UT
Park City Mountain Resort, Park City, UT

This project examined controlling weeds using grazing by goats versus treatment with the herbicide milestone.

Treatments: 1) Control 2) Milestone 3) Graze once 4) Graze twice (See below)

Herbicide Results: Observation Date: 7/19/07

  • Musk thistle: 90-95% control
  • Russian and spotted knapweed - 90% control
  • Dalmatian toadflax - 10% control (weeds only turned yellow)

Grazing Results:
First Grazing: Observation Date: 06/29/07

  • Musk Thistle - 50% of rosettes/ bolted plants grazed
  • Russian/Spotted Knapweeds - 90% grazed down to crowns
  • Dalmatian Toadflax - little signs of grazing effect on plant

Second Grazing: Observation Date: 07/19/07

  • Musk Thistle - 25% control, 50 - 75% bolted with seed heads formed. Remaining 25% grazed to rosette stage.
  • Russian/Spotted Knapweed - 90% of plants grazed down to crowns, six - eight inches of regrowth occurred after grazing, no seed heads formed on regrowth.
  • Dalmatian toadflax - 50% of stems were stripped of leaves, plants appeared to be stressed.


  1. Milestone herbicide is an effective weed control option for thistle and knapweed control.
  2. Grazing weed can be an effective weed control option; however, more than one year of grazing is required.
  3. Herding grazing goats is not as effective as penning grazing goats in electric fence pens to control weeds.
  4. Weeds need to be grazed at least twice during the growing season to reduce the seed source for the following year.
  5. Using a combination of grazing and herbicide treatments can be an effective weed control option especially in sensitive areas.
  6. Goats can prevent flowering of musk thistle using repeated grazing.
  7. Goats must graze knapweeds repeatedly (at least twice) during the growing season to prevent plants from producing seeds.
For further information contact:
Sterling Banks sterling.banks@usu.edu
Summit County Extension Utah State University
45 East 100 North; Coalville, UT
(435) 336-3219, 615-3219 or 783-4351, ext. 3219