Green’s Dictionary of Slang

(Aus.) a horse.

1929		Sun. Times (Perth) 10 Nov. 65/8: I’m drivin’me Jack McNab down the field of wheat, an’ I makes a swipe at the applesauce with me egg-flip and I cops a pea over the dial.
1984		J. Meredith Learn to Talk the Old Jack Lang 19: apple sauce: horse .
2001		Krackatinni’s Aus. Rhy. Sl. 🌐 Apple sauce = a horse.
2002		Little Bitch from Down Under 🌐 Apple sauce – horse. Usage: She’s a great little apple sauce.