Green’s Dictionary of Slang

(Aus.) a cow, a bullock; thus horney-steerer, a bullock-driver; thus used generically for the beef interest.

1905		Bulletin (Sydney) 27 July16/4: [A] bullock-driver is called a bullocky, a bovine-puncher, an ox-persuader, a horny-steerer, a cow-puncher, a buffalo-navigator, a steer-pilot, and goodness knows what else.
1910		Bulletin (Sydney) 22 Sept. 36/1: Now the voice of Jumbuck, Horny and Co. is being heard in the land: ‘interfering with Private Enterprise’.
1922		Joyce Ulysses 406: Nix for the hornies.
1938		X. Herbert Capricornia (1939) 273: [They] rode in looking for Clean Skins, or unbranded beasts, and for Hornies, or beasts with ingrowing horns.
1941		Baker Popular Dict. Aus. Sl. 40: Horney-steerer, a bullock driver.
1957		J. Greenway ‘Australian Cattle Lingo’ in AS XXXIII:3 166: hornies, n. Cattle.