Certain breeding practices such as overly relying on inbreeding or line breeding can increase the possibility of dogs carrying defective genes and passing these genes on to their offspring. Many "backyard" breeders and puppymills have no idea of the genetic backgrounds of their dogs and therefore have no idea of any defective genes these dogs may be carrying. Fifi and Fido may look cute but to breed them without knowing (or in some cases without caring) if they are carriers of bad stifles, retained testicles, incomplete tear ducts, legg-perthes, degenerative osteoarthritis, PRACD, etc. is irresponsible and the consequences can be devastating for the offspring and their owners. There is a term used to describe breeders who refuse to see or admit to the problems in their lines and that term is Kennel Blind. This link will take you to an excellent article from the AKC defining Kennel Blindness. Here is an excerpt from the article.

"Found in many purebred dog kennels, kennel blindness is a “disease” that results in breeders’ inability or refusal to admit to the failings in their own lines of dogs, whether they relate to conformation traits described in the AKC breed standards, behavior or genetic disease. Kennel-blind breeders are given to justifying the dogs they breed by developing warped and unrealistic interpretations of their breed’s standard, said Ann Seranne in her book, The Joy of Breeding Your Own Show Dog."

When you are looking for a new puppy, ask the breeder about their breeding practice beliefs. Ask about the prevalence of the health issues (see below) that have cropped up in their lines. If a breeder tells you they have never had any health issues with their dogs-find another breeder, an honest one!

Ask the breeder if they periodically contact people who have puppies from them. Some of these problems don't show up for several years. A good, responsible breeder WANTS and NEEDS to know if there are health issues in their dogs!

A good breeder cares about the puppies they produce for their entire life. If a health problem does arise, you want to know that the breeder will still be there for you. When you are already dealing with the emotional upheaval of having a dog who is suffering from health problems, you don't need the added emotional stress of having the breeder blame YOU for those problems if they are genetic in origin.

A good way to learn about a potential breeder is to join several of the Internet groups that exist. Ask the members if they know of this breeder and if they know of people who have dogs from the breeder. The more you learn, the better. Do not just assume that because a breeder has been breeding for a long time or because they have bred many champions that they are necessarily breeding healthy dogs.

Degenerative Osteoarthritis-results from destruction of the cartilage that protects the bones that make up the joint.

Canine Demodicosis-a disease caused by a mite (Demodex canis) that lives deep in the hair follicles. This mite is transmitted from the bitch to the offspring during suckling and is found in small numbers on all dogs. It is believed that these mites may initially cause problems in dogs due to an immulogic or genetic disorder. This can occur in two "general" ages of dogs. One group is less than 2 years old at onset--junvenile demodicosis. The other age group affected is older dogs-adult onset demodicosis.

Congestive heart failure is a condition in which the heart can't pump enough blood to the body's other organs.
The heart keeps working but not as efficiently as it should. As blood flow out of the heart slows, blood returning to the heart through the veins backs up, causing congestion in the tissues. Often swelling results. Sometimes fluid collects in the lungs and interferes with breathing, causing shortness of breath, especially when lying down. Heart failure also affects the kidneys' ability to dispose of sodium and water.

(http://www.americanheart.org/presenter.jhtml?identifier=4585)

The following information is from http://www.napoleon.org.uk/health/poodlehealth.htm

Progressive Retinal Atrophy a disorder of the eye in which the light cells in the retina wither and die due to insufficient blood supply. the disease progresses Gradually, results in blindness and has no known cure. Its onset in the Poodle is between 5 to 6 years old. The presence of PRA can be detected by ophthalmascopic examination by a veterinary ophthalmologist.

Corneal Dystrophy - Corneal dystrophies" are diseases of the cornea that are bilateral, non-inflammatory and inherited.

Legg-Calve'-Perthes - a disorder in which non-inflammatory a vascular necrosis of the femoral neck and head result in one of both of a young dog's rear legs becoming lame. Irritability and pain are other primary symptoms. Some dogs recover and function without treatment, but in severe case surgical removal of the femur head is indicated.

Patella Sub-luxation - or slipped kneecap, a condition in which the patella slides in and out of the groove where it is normally held in place by ligaments. This causes hopping or favoring of the leg until the kneecap slips back into place. In some cases, in can be surgically corrected.

Epilepsy - a neurological disorder marked by recurring seizures that follow episodic, abnormal discharges of electrical impulses by nerve cells in the brain. As in humans, it is controlled with drugs such as Phenobarbital or Dilantin.

Hypothyroidism - a condition resulting from an inadequate production of thyroid hormone. Also treated with drug therapy, its symptoms include a coarse, brittle coat that falls out, thickening and discoloration of the skin, lethargy, obesity, mental slowness and irregular heart cycles.

Cryptorchidism - or undescended testicle, a condition in which one or both testicles are retained in the abdominal cavity. Hormone injections, given to stimulate testicular descent, sometimes are successful. When the treatment is unsuccessful, removal of the testicles is recommended because cryptorchid testicles may become cancerous.

Mitral Valve Disease - The heart consists of 4 chambers - 2 atria and 2 ventricles. The atrioventricular (AV) valves ensure that the blood flows from the atria to the ventricles when the heart beats. A defect in the mitral valve (the left atrioventricular valve) causes backflow of blood into the left atrium, or mitral regurgitation. Less commonly, a narrowing or stenosis of the valve can be identified. Because of the leaky valve, the heart is less efficient at pumping blood to the body.

Autoimmune Hemolytic Anemia (AIHA) - A decrease in the number of red blood cells (RBC's) or the amount of hemoglobin, resulting in a decrease in the oxygen- carrying capacity of the blood.

Cushings Disease - This is a disease that occurs from the overproduction of cortisone by the adrenal glands.

Addisons Disease - A disorder caused by a deficiency in adreno cortical hormonesmost commonly occurring in young to middle aged dogs.

Liver Shunts - Liver Shunts are abnormal vascular connections between the hepatic portal vein and systemic circulation. Such anomalies cause blood in the gastrointestinal tract to be diverted past the liver, there by limiting the liver's vital functions in metabolism and detoxification of compounds.

Entropian - An eye condition in which the eyelids are grown inward, causing the eye lashes to come into contact with the eye itself.

Autoimmune Disease - If a dog has an autoimmune disease, the immune system mistakenly attacks self, targeting the cells, tissues, and organs of a dogs own body. A collection of immune system cells and molecules at a target site is broadly referred to as inflammation.

Lupus - This is a rare disease of the immune system. In this disease, the immune system forms antibodies against the nuclear component of its own cells.

The following information is from

http://www.avma.org/careforanimals/animatedjourneys/pethealth/canine.asp

Heart disease - Can be either present at birth or acquired, often developing during middle age. Acquired heart disease is more common, affecting many older dogs.

Heartworm - Once in the dog's heart, the worms can grow to as long as 14 inches and cause significant damage to the heart, lungs and other vital organs. If left untreated, heartworm disease can result in death.

Canine distemper - a highly contagious disease caused by a virus. Canine distemper virus is most often transmitted through contact with respiratory secretions. Contact with the urine and fecal material of infected dogs can also result in infection. Younger dogs and puppies are the most susceptible to infection. Among puppies, the death rate from distemper often reaches 80%. The disease also strikes older dogs, although much less frequently. Even if a dog does not die from the disease, its health may be permanently impaired. A bout with canine distemper can leave a dog's nervous system irreparably damaged, along with its sense of smell, hearing or sight. Partial or total paralysis is not uncommon, and other diseases — particularly pneumonia — frequently strike dogs already weakened by a distemper infection.

Canine Parvovirus - a highly contagious viral disease that attacks the intestinal track, white blood cells, and in some cases the heart muscle.

Canine Bordetellosis (Kennel Cough) - caused by bacterium Bordetella bronchiseptica which is present in the respiratory tracts of many animals. It is a primary cause of tracheobronchitis (kennel cough) which results in a severe chronic cough. In addition to the cough, some dogs develop a nasal discharge. Transmission most frequently occurs by contact with the nasal secretions of infected dogs.

Parainfluenza - caused by a virus which produces a mild respiratory tract infection. It is often associated with other respiratory tract viruses. In combination these viruses are usually transmitted by contact with the nasal secretions of infected dogs

Diarrhea and vomiting - Diarrhea is not a disease; rather, it is a symptom of many different diseases. Many mild cases of diarrhea can be resolved quickly with simple treatments. Others are the result of fatal illnesses, such as cancer. Even diarrhea caused by mild illnesses may become fatal if treatment is not begun early enough to prevent severe fluid and nutrient losses. Some of the minor causes of diarrhea include stomach or intestinal viruses, intestinal parasites, and dietary indiscretions (such as eating garbage or other offensive or irritating materials). (http://www.sniksnak.com/doghealth/diarrhea.html)