Glossary

Score & methodology terms

Breed Health Score

Our single 0 to 100 score for a breed (higher is healthier), combining longevity (65%), conformation risk (20%) and hereditary disease burden (15%). See the methodology.

Longevity

How long the breed typically lives. Based on median lifespan from a peer-reviewed study of 584,734 UK dogs (McMillan 2024). A higher score means longer-lived.

Median lifespan

The midpoint age at death for the breed in the study: half of dogs lived longer, half shorter. It is a population figure, not a prediction for any one dog.

Conformation

Health risk from body shape. We deduct points for flat-faced (brachycephalic) breeds and for giant size, which carry known breathing, joint and heart risks.

Brachycephalic (flat-faced)

Flat-faced skull shape (for example Pug or Bulldog). Linked to breathing difficulty (BOAS), eye and skin problems.

BOAS

Brachycephalic Obstructive Airway Syndrome: the breathing difficulty common in flat-faced breeds, caused by narrowed airways.

Giant breed

The largest size category (for example Great Dane, Mastiff). Giant breeds tend to live shorter lives and carry higher joint, heart and bloat risk.

Hereditary disease burden

The load of known hereditary conditions: a count of reported conditions weighted for severity. It carries the least weight because better-studied breeds tend to have more conditions on record.

Grade

A simple A to E band based on the overall 0 to 100 score. A is healthiest, E is most at risk.

Provisional score

A score shown when we do not yet have condition data for a breed, so it is based on longevity and conformation only.

CC-BY

A Creative Commons licence that lets us reuse and publish the underlying lifespan data as long as we credit the source.

Common health conditions

Short, plain-English definitions of the conditions referenced across breed profiles. Each links to the full overview and the breeds most associated with it.

Hip dysplasia

A developmental condition where the hip joint forms abnormally, so the ball and socket fit loosely and rub. It leads to pain, stiffness, reduced activity and eventually arthritis, and can affect a dog's mobility for life. Hip dysplasia in dogs →

Elbow dysplasia

A group of developmental abnormalities of the elbow joint that cause the surfaces to fit poorly. It leads to front-leg lameness, stiffness and early arthritis, typically appearing in young large-breed dogs. Elbow dysplasia in dogs →

Patellar luxation

The kneecap slips out of its normal groove, often to the inside of the leg. Signs include an intermittent skipping or hopping gait and occasional lameness. It can range from mild to severe and may cause arthritis over time. Patellar luxation in dogs →

Cruciate ligament rupture

Tearing of a key stabilising ligament inside the knee, causing sudden lameness and instability in the joint. It leads to pain, difficulty bearing weight and, if untreated, arthritis in the affected leg. Cruciate ligament rupture in dogs →

IVDD

Intervertebral disc disease occurs when the cushioning discs between the spinal bones bulge or rupture, pressing on the spinal cord. It causes pain, weakness and sometimes paralysis, and is common in long-backed breeds. IVDD in dogs →

Osteoarthritis

A long-term joint condition where the protective cartilage wears away, so bones rub together within the joint. It causes pain, stiffness, swelling and reduced mobility that tends to worsen gradually with age. Osteoarthritis in dogs →

GDV (bloat)

A life-threatening emergency where the stomach fills with gas and twists, cutting off blood flow. Signs include a swollen belly, unproductive retching and distress. Without rapid surgery it is often fatal, especially in large, deep-chested breeds. GDV (bloat) in dogs →

Progressive retinal atrophy

An inherited group of diseases in which the retina gradually degenerates. Dogs first lose night vision and struggle in dim light, then progress to complete, permanent blindness. It is painless but irreversible. Progressive retinal atrophy in dogs →

Cataracts

The normally clear lens of the eye becomes cloudy, blocking light from reaching the retina. This causes blurred vision and, if advanced, blindness. Cataracts can be inherited or linked to diabetes and other conditions. Cataracts in dogs →

Cherry eye

The tear gland of the third eyelid slips out of place and bulges as a red mass in the corner of the eye. It can cause irritation and dryness, and is usually repositioned surgically to preserve tear production. Cherry eye in dogs →

Entropion

The eyelid rolls inward, so eyelashes and hair rub against the surface of the eye. This causes irritation, tearing, squinting and, if untreated, painful corneal damage. It is often inherited and usually corrected with surgery. Entropion in dogs →

Ectropion

The lower eyelid rolls or droops outward, exposing the inner surface and leaving the eye vulnerable. It can cause dryness, irritation, tearing and recurrent conjunctivitis, and is common in breeds with loose facial skin. Ectropion in dogs →

Dry eye

A condition where the eyes do not produce enough tears, so they become dry, red, sore and prone to sticky discharge and ulcers. Left untreated it can cause pain, scarring and reduced vision. Dry eye in dogs →

Glaucoma

Pressure inside the eye rises to damaging levels, harming the retina and optic nerve. It causes a painful, red, often cloudy or bulging eye and can lead to rapid, permanent blindness. It is a veterinary emergency. Glaucoma in dogs →

Epilepsy

A neurological disorder causing recurrent seizures, often with no identifiable underlying cause. Seizures can involve collapse, muscle twitching, paddling and loss of awareness. It is usually a lifelong condition managed with medication. Epilepsy in dogs →

Syringomyelia

A painful condition where fluid-filled cavities form within the spinal cord, often linked to a skull that is too small for the brain. It causes neck pain, sensitivity to touch and repeated scratching at the air near the neck. Syringomyelia in dogs →

Chiari-like malformation

A condition where the skull is too small for the back of the brain, crowding it and disrupting the flow of fluid around the brain and spine. It can cause pain, sensitivity around the head and neck, and scratching movements. Chiari-like malformation in dogs →

Degenerative myelopathy

A progressive, inherited disease of the spinal cord in older dogs. It gradually causes hind-limb weakness, wobbliness and dragging of the paws, advancing to paralysis. It is painless but incurable and shortens quality of life. Degenerative myelopathy in dogs →

Wobbler syndrome

A condition where compression of the spinal cord in the neck causes an unsteady, wobbly gait, particularly in the hind legs. Affected dogs may stumble, have a swaying walk and, in severe cases, become weak or paralysed. Wobbler syndrome in dogs →

Mitral valve disease

Degeneration of the heart's mitral valve lets blood leak backwards, straining the heart. It typically causes a murmur first, then coughing, breathlessness and eventually heart failure. It is the most common heart disease in small older dogs. Mitral valve disease in dogs →

Dilated cardiomyopathy

The heart muscle becomes thin and weak, so the enlarged heart pumps poorly. It can lead to abnormal rhythms, coughing, weakness, fainting and heart failure. It is most common in large breeds and can appear suddenly. Dilated cardiomyopathy in dogs →

Hypothyroidism

The thyroid gland produces too little hormone, slowing the body's metabolism. Common signs are weight gain, lethargy, hair loss and skin problems. It is usually manageable for life with daily replacement hormone. Hypothyroidism in dogs →

Cushing's disease

A hormonal disorder where the body produces too much cortisol, the stress hormone. It causes increased thirst, hunger and urination, a pot-bellied appearance, hair loss and thinning skin, and develops gradually over time. Cushing's disease in dogs →

Addison's disease

The adrenal glands produce too little of key hormones like cortisol. Signs are often vague, including weakness, vomiting, weight loss and lethargy, and can escalate into a life-threatening crisis. It is manageable for life with medication. Addison's disease in dogs →

Diabetes mellitus

A condition where the body cannot properly regulate blood sugar due to lack of, or resistance to, insulin. Signs include increased thirst, urination, hunger and weight loss. It usually requires lifelong insulin and dietary management. Diabetes mellitus in dogs →

Pancreatitis

Inflammation of the pancreas, the organ that helps digest food and control blood sugar, which can be sudden or recurring. It causes vomiting, abdominal pain, loss of appetite and lethargy, and can become serious. Pancreatitis in dogs →

Atopic dermatitis

A chronic, inherited allergic skin disease triggered by environmental allergens such as pollen, dust mites or mould. It causes intense itching, redness and recurrent skin and ear infections, and often needs lifelong management. Atopic dermatitis in dogs →

Allergies

An overreaction of the immune system to substances such as foods, fleas or environmental allergens. In dogs this usually shows as itchy skin, ear infections or digestive upset rather than sneezing. It often needs ongoing management. Allergies in dogs →

Cancer

A broad term for diseases where abnormal cells grow uncontrollably and can spread through the body. Signs vary widely depending on the type and location. It is a leading cause of death in older dogs. Cancer in dogs →

Mast cell tumours

A common skin cancer arising from immune cells that release inflammatory chemicals. Tumours vary widely, from slow-growing lumps to aggressive, spreading masses, and can cause swelling, redness and ulceration. Behaviour ranges from benign to malignant. Mast cell tumours in dogs →

Von Willebrand disease

An inherited blood-clotting disorder caused by a deficiency of a protein needed for platelets to stick together. Affected dogs bruise easily and may bleed excessively from minor wounds, surgery or in the urine or gums. Von Willebrand disease in dogs →

Tracheal collapse

The windpipe weakens and flattens, narrowing the airway. It causes a characteristic honking cough, wheezing and breathing difficulty, especially with excitement or exercise. It is most common in small and toy breeds and tends to worsen over time. Tracheal collapse in dogs →

Obesity

Excess body fat that strains the joints, heart and organs. It increases the risk of arthritis, diabetes and reduced lifespan, and can worsen breathing and mobility. It is common and largely preventable through diet and exercise. Obesity in dogs →

Dental disease

Build-up of plaque and tartar leads to inflamed gums, infection and tooth decay. Signs include bad breath, sore mouth and difficulty eating. Untreated, it causes pain, tooth loss and can affect overall health. Dental disease in dogs →