Hi

If you are wanting to take the pick of the litter, then you've got to think about what your dog has to offer as a stud dog. Perhaps if your dog is absolutely outstanding at flyball, then someone may express an interest in using him at stud. But I reiterate my comments about health tests. Anyone who doesn't ask for proof of results of health tests is either a puppy farmer or has failed to do the research that is vital for responsible dog breeding.

In answer to your question - yes, using a dog at stud can change it and make it much harder to handle when other dogs are about. They can become permanently on the look out for bitches, they can become far less tolerant of other males and they can start marking in the house.

To be honest, my best advice to you, if you are wanting a dog like the one you already have, is to go back to your breeder (if they are responsible and health test!) and to buy a relative of your dog.