Many factors affect the future health of a dog. While it is not possible to know some of these factors, other factors can be determined by observation and examination.
A healthy dog will not have eye or nasal discharge, will not show signs of diarrhea or a bloated stomach, and will be alert, active, and interested in its surroundings and new people. Ideally, the dog will already be "vet-checked" and free of heart murmurs and other obvious congenital defects.
If you are adopting a puppy or dog from a shelter or rescue organization, it may already have been examined by a veterinarian and spayed or neutered. It will likely have had basic shots as well as parasite treatment. You should follow up with a trip to your own veterinarian shortly after the dog comes home (usually within 48 hours) and then follow his or her recommendations for additional treatment and preventative care. Feeding a good-quality dog food, giving regular exercise, training, grooming, and preventative veterinary care will go a long way toward helping your dog lead a healthy life. However, you may have little information about the dog's genetic background or whether there's a likelihood that it could develop breed-related issues.
If you are looking to buy a purebred dog, you should have more information about the genetic health issues of the breed. Responsible breeders are knowledgeable about breed health issues and will have done testing on the parents. Some health tests are phenotype tests, which tell you whether the dog is expressing a specific disease. An example is the test for hip dysplasia. Breeds prone to this disease and that are used for breeding should be X-rayed to make sure they have good hips. That doesn’t guarantee a dog's offspring will not inherit the combination of genes that make it susceptible to hip dysplasia, but it does increase the odds of selecting a dog with good hips.
Other tests increasingly available are DNA tests that look for genetic markers linked to specific diseases. If both parents have been tested and found to be negative for a specific disease-related gene, offspring can be guaranteed to be free of that disease. Ask the breeder what tests he or she has done on the parents and ask to see certificates of proof of normal status. A good source of information on health testing of purebred dogs is the Orthopedic Foundation for Animals (www.offa.org). The organization maintains a searchable database that can be used to verify health testing on not only the parents of the dog you are considering but often on several generations of the pedigree. OFFA also maintains a large database on dog health and coordinates with other health registries so you can find all the test results on most dogs in one convenient location. Another good source of information on canine health testing is the Canine Health Information Center (CHIC) (www.caninehealthinfo.org). Parent clubs of many popular breeds have established recommended testing for their breeds. The program is voluntary, but many reputable breeders are now using the CHIC standards as a benchmark for testing.
In addition to screening breeding stock for heritable diseases, reputable breeders will keep their dogs healthy through diet, exercise, sanitary facilities, and regular preventative care. A puppy you purchase should have proof of at least first shots and a veterinary examination. The breeder should be able to show you how to prevent and treat for parasites, and the dogs should all appear healthy and happy. Dogs raised with a lot of daily human contact will adapt to their new family much more quickly than dogs raised in a kennel situation.
