The Collaborative International Dictionary of English v.0.48:
Stirk \Stirk\, n. [AS. stric, from ste['o]r a steer. See Steer a young ox.] A young bullock or heifer. [Prov. Eng. & Scot.] --Sir W. Scott. [1913 Webster]WordNet (r) 3.0 (2006):
stirk n 1: yearling heifer or bullock