Someone on a forum is saying they got there male dog the jab so he cant preduce sperm?  I did ask if she ment the implant, but she said no, its a Jab. this is news to me. Is there such a jab ?

Maybe they're referring to Tardak.

dose it stop him making puppies?

Not guaranteed; it's designed to treat hypersexuality (over-sexedness!) as well as prostate tumours and anal tumours. It can be used on stud dogs but they may show temporary reduced fertility or libido, but not always.