Green’s Dictionary of Slang

1. (Aus./N.Z.) a sheep-shearer, spec. one who works in the catching sheds, filling the catching pens.

1900		Bulletin (Sydney) 13 Jan. 32/2: Others, the sheep-ho’s, the engine-drivers at the shed or wool-wash, call him, if he does sleep.
1912		Decatur Herald (IL) 8 May 2/7: ‘You would get a name’ [...] ‘What would it be?’ ‘Oh — Sheepo’.
1940		(con. 1870s) E.C. Studholme Te Waimate (1954) 130: The shearers were, of course, the autocrats of the shed, but the ‘sheep-oh’ (penner -up) also held an important position.

2. (N.Z.) a shepherd, a musterer of sheep into pens.

1988		McGill Dict. of Kiwi Sl. 99/2: sheepo shepherd.
2003		McGill Reed Dict. of N.Z. Sl. 184: sheepo Shepherd, specifically the musterer of sheep into pens, from the cry employed. ANZ early C20.