Bobcat 334 Hydraulic Oil

I borrowed a Bobcat 334 from a friend to dig a small ditch on our property. It belonged to his dad that passed away and hasn’t been ran in years. I told him when I used it some and saw what needed fixing up a little that I’d get it back in decent working condition. First problem as usual are the hydraulic leaks. It’s barely has any fluid in it. My question is can you run universal hydraulic tractor fluid in it? He said he was pretty sure that’s what his dad used in instead of buying the Bobcat brand stuff.