Equine animals (6)
I believe the answer is:
horses
'equine animals' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for horses that I've seen before include "Equines" , "Hoofed mammals (which go with 19 4)" , "Eg, stallions" , "Steeds" , "Equine beasts" .)