Boer goats consume 75% leaves and 25% grass. Their diet includes a variety of grasses including tussocky and woody species, weeds, shrubs and the leaves of larger trees that are within reach.
Boer goats also eat blackberries, briars etc.

You should avoid clovers and lush grasses.

These links have some information on the subject.

http://boergoat.une.edu.au/meatmrk2.htm

Also take a look at:
http://www.boergoats.com/niekerk1.htm

and
http://studbook.co.za/boergoat/value.html