The Collaborative International Dictionary of English v.0.48:

Troat \Troat\, v. i. [Either onomatopoetic, or akin to throat.]
   To cry, as a buck in rutting time.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Troat \Troat\, n.
   The cry of a buck in rutting time.
   [1913 Webster]

WordNet (r) 3.0 (2006):

troat
    v 1: emit a cry intended to attract other animals; used
         especially of animals at rutting time