What is the meaning of "Шню"?

Question

I am quite a beginner, and I am studying Russian language by myself.
Currently I am trying to learn by translating some fairy tale from Народные русские сказки, by Афанасьев.

There is this one fairy tale in which a fox says

«Шню, шню, бычок, соломенный бочок! Сани чужие, хомут не свой, погоняй — не стой!»

What does "шню" mean?

By the way, if you could tell me also the correct translation of the whole sentence, it would be great!

If anyone is interested, the title of the fairy tale is "За лапоток — курочку, за курочку — гусочку"

Answer 1

I've never come across this interjection/exclamation, but judging by the context it's a word of spurring/speeding a draft animal much like giddyup, hyah, hait etc.

The most known such Russian word is Но! which is / used to be said to spur a horse.

^{Of course that's a matter of personal taste, but i wouldn't start learning English from Shakespear or Chinese from Book of Songs, just because they're written in an archaic (or dialectal) language. I believe a more natural course would be the opposite - from modern and standard language to archaic and dialectal}