Vulgar thing cattle often do (3)
I believe the answer is:
low
I believe this clue is a double definition.
'vulgar' is the first definition.
(thesaurus)
'thing cattle often do' is the second definition.
(to low is to make a mooing sound)
(Other definitions for low that I've seen before include "SECOND PART OF 14" , "sound from Hereford?" , "Inferior; not loud" , "Not high or tall" , "Not high or loud" .)