His cattle wandering off track, perhaps (9)
I believe the answer is:
athletics
'track perhaps' is the definition.
(track is a kind of athletics)
'his cattle wandering off' is the wordplay.
'wandering off' is an anagram indicator (I've seen this in other clues).
'his'+'cattle'='hiscattle'
'hiscattle' anagrammed gives 'ATHLETICS'.
(Other definitions for athletics that I've seen before include "Sports -- cheat list (anag)" , "Running and jumping" , "Partly track" , "Physical sports for trained competitors" , "Lithe acts performed in physical sports" .)