Disease in cattle fed string -- feed on grass (6)
I believe the answer is:
browse
'grass' is the definition.
The answer and definition can be both related to consumption as well as being verbs in their base form.
Perhaps you can see an association between them that I can't see?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for browse that I've seen before include "Read idly" , "Surf (the Internet)" , "Leaf through (a book)" , "Look through in a random way, a book or shop, say" , "Read casually" .)