What does it mean to 'cut' a horse?

Question

Is that to geld them?

Answer 1

You answered your own question- this does indeed mean to geld or castrate a male horse.

Answer 2

If you're talking about a cutting horse it's something you see at the rodeo where they  separate a steer from the herd and the horse needs to keep it separated.  Where ever the cow moves closer to herd, the horse 'cuts' her off.  The horse does this without the rider doing anything except sitting in the saddle, it's all up to the horse.

I may have gotten some of the terms wrong, but that's it in a nutshell.

Answer 3

To "Cut" a horse means to geld them.

However a "Cutting" horse is a type of Quarterhorse used for rodeo and ranching...

Answer 4

Yeah, it means to geld them.