We bought our first goats for brush control  And they have done an exception job!  We frequently sell goats for brush control and have had positive responses from the new owners.

Michelle from BRC Boer goats http://www.brcboers.com/ suggests 8-10 adult animals per acre for one season brush clearing for dense brush(blackberries, vine maple, buck brush, weeds, wild cherry, heavy poison oak or sumac). 4-6 animals per acre for one season brush clearing in developed timber with light brush.

Or, if you prefer to have the professionals come in and do the job for you:

Rent-A-Ruminant, LLC is owned by Tammy Dunakin, chief Goat Wrangler and is located on Vashon Island in the Seattle area, P.O. Box 1345 Vashon, WA 98070, 206.251.1051.  http://rent-a-ruminant.mapmate.com/maps/1061

or

Don Miller at Goat Trimmers,  http://www.goattrimmers.com/about_us.htm  

This is a picture of Richard and Sandy's Boer Goats hard at work mowing down blackberries and other brush on our neighbors property.  After seeing what the goats did with our brush problem, they asked to have a few come over for an extended visit!
Boer Goats are great
for brush control
RICHARD & SANDY'S BOER GOAT FARM