Mounted team that collects live goat (4)
I believe the answer is:
ibex
'goat' is the definition.
(ibex is a kind of goat)
'mounted team that collects live' is the wordplay.
'mounted' shows that the letters should be reversed in order.
'team' becomes 'XI' (a football team, from Roman numerals for 11).
'that collects' is an insertion indicator.
'live' becomes 'be' (synonyms).
'xi' written backwards gives 'ix'.
'ix' going around 'be' is 'IBEX'.
(Other definitions for ibex that I've seen before include "Come out of an egg" , "Mountain goat with curving horns" , "Mountain-goat" , "Large-horned mountain goat" , "Pyrenean mountain goat" .)