So, you have chosen to breed your Great Swiss Mountain Dogs! Assuming you are familiar with standard canine breeding practices and procedures, once you know the basics, there are still a few things that you should know beforehand to make the experience as healthy as possible for your pet as it can be and as stress free for yourself as possible.
First, understand that before breeding any dogs, your dog should receive a complete physical examination, letting the veterinarian know that you are planning on breeding your dog. When you are choosing a sire for your litter, consider such things as examining the registration papers, certificate of health (or health clearance from the Canine Health Information Center), a certification that the breeding stock is unaffected by eye disorders by the Canine Eye Registry Foundation, and pedigree (paying particularly close attention to existence of hereditary conditions such as epilepsy, gastric torsion or bloat, and hip disorders). If all of these things are satisfactory, a simple visual inspection will go a long way in assuring that you are breeding with a dog in possession of the characteristics that will allow you to capitalize on your dog's positive characteristics and downplay the characteristics that you deem less desirable.
Spend some time with the Great Swiss Mountain Dog you plan to use for stud service. It is accepted as truth by most breeders that some personality characteristics are genetic in nature and may be passed on. If you want to avoid whelps with aggressive natures, try to avoid breeding with overly aggressive sires. If your potential sire appears to possess the pedigree, physical, mental, emotional, and health characteristics you deem desirable, then it is a good bet you have chosen a good sire for breeding.
With all this being said, particularly in breeds where demand outweighs supply, there are currently many co-ownerships involved when buying puppies. One type of co-ownership is perfectly acceptable not just for Great Swiss Mountain Dog owners but almost any pet owners. It is a co-ownership in which the breeder retains partial ownership on paper until the puppy has reached an acceptable breeding age, and received health clearances. This type of co-ownership is used basically to ensure that the integrity of the breed and the best interest of the pup is retained by making it impossible to register a litter unless the dog is old enough to breed and all shots and health clearances have been given.
The other type of co-ownership is highly frowned upon in breeding circles. Many times, breeders will retain partial ownership with the buyer with the sole intent of forcing the person who has purchased the puppy to breed it. Most times at least one puppy is required as an additional "Payment" on top of the purchase price of the animal. Sometimes, it is required that the dog be bred and all pups be forfeited for the entire breeding life of the animal. This is a very high hidden cost for pet ownership, and is considered unscrupulous by most legitimate breeders. No owner should be forced to breed an animal, nor should they be forced to pay for an animal many times over the initial purchase price by giving up any litters the animal might produce.
Knowing the basics and breed particulars will make breeding your Great Swiss Mountain Dog a successful and rewarding experience for everyone involved.