Witnessed starving troubadour in cattle fodder (5)
I believe the answer is:
straw
'cattle fodder' is the definition.
'straw' can be an answer for 'fodder' (I've seen this in another clue). I'm unsure of the 'cattle' bit.
'witnessed starving troubadour in' is the wordplay.
'witnessed' becomes 'saw' ('see' can be a synonym of 'witness').
'starving troubadour' becomes 'tr' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'in' indicates putting letters inside.
'saw' enclosing 'tr' is 'STRAW'.
Can you help me to learn more?
(Other definitions for straw that I've seen before include "trifle" , "Dry stalks" , "In the wind, it's an indication" , "Dried stalks; yellow" , "Thatching material" .)