If a male dog has been used for stud, even if he's later neutured you still may have opened the door to having him "mark". Once a male dog starts marking its an instinctive behaviour and often unbreakable. He may end up wearing belly bands to save your house, furniture and carpets. If thats not enough of an incentive to not use him for stud I don't know what is. Also, the bitch he is mated with should have testing for venerial diseases (dogs get STD's too!), and also it is usually the responsiblity of the male dogs owner to ensure the mating takes place. Since he is inexperienced he may need help to stay in position and form a lock on the female. She also may be super nasty and can potentially harm him if she is not receptive to his advances.. Unless one is planning on developing a breeding program and showing their dogs, they shouldn't be breeding at all. IMHO.