Collie
The Collie is an elegant, intelligent herding breed made famous by the fictional Lassie, and the real dog lives up to much of the legend. Available in Rough (long-coated) and Smooth (short-coated) varieties, Collies are gentle, loyal, and remarkably intuitive with their families. They are one of the most family-friendly breeds in existence, combining intelligence and trainability with a sensitive, devoted temperament that makes them outstanding companions and therapy dogs.
12–14
years lifespan
60–75
lbs (male)
24–26
inches tall (male)
moderate
energy level
Temperament
How Old Is Your Collie in Human Years?
Use our breed-specific calculator to find out, plus get personalised health and care guidance for your dog’s exact age.
Open Collie Age CalculatorCommon Health Conditions
MDR1 Gene Mutation (Multi-Drug Resistance 1)
Approximately 70% of Collies carry the MDR1 gene mutation, which causes a defective blood-brain barrier that allows certain drugs to accumulate to toxic levels in the brain. Affected dogs can experience severe neurological reactions — including seizures, coma, and death — from common medications including ivermectin (at high doses), loperamide, and certain anaesthetics, sedatives, and chemotherapy drugs. This is the most important breed-specific health concern for Collie owners to understand.
Typical onset: 0–0 years
Collie Eye Anomaly (CEA)
Collie Eye Anomaly is an inherited developmental condition affecting the choroid (blood vessel layer) of the eye. It ranges from mild choroidal hypoplasia (often not clinically significant) to severe colobomas and retinal detachments that can cause blindness. CEA is present from birth and does not progress after about 8 weeks of age, meaning the severity at the initial examination is the lifetime severity. Approximately 70-90% of Collies are affected to some degree.
Typical onset: 0–0 years
Progressive Retinal Atrophy (PRA — rcd2 form)
Rod-cone dysplasia type 2 (rcd2) is the form of progressive retinal atrophy specific to Collies. It causes degeneration of the photoreceptor cells in the retina, beginning with rod cells (causing night blindness) and eventually affecting cone cells (causing complete blindness). Unlike CEA, PRA is progressive and eventually leads to total vision loss. However, dogs typically adapt well over the gradual course of the disease.
Typical onset: 1–5 years
Dermatomyositis (DMS)
Dermatomyositis is an inflammatory disease affecting the skin and muscles that is unique to Collies and Shetland Sheepdogs. It causes skin lesions (crusting, hair loss, scarring) typically on the face, ears, tail tip, and bony prominences, along with muscle inflammation that can cause difficulty eating and moving. The condition ranges from mild skin-only involvement to severe systemic disease. It is hereditary but triggered by environmental factors including UV exposure and viral infections.
Typical onset: 0.25–1 years
Bloat/Gastric Dilatation-Volvulus (GDV)
Collies have a moderately deep chest that places them at elevated risk for bloat, though not at the extreme levels of giant or very deep-chested breeds. GDV occurs when the stomach fills with gas and potentially rotates, cutting off blood supply. It is a life-threatening emergency requiring immediate surgical intervention. The risk increases with age and is higher in dogs that eat rapidly, exercise near mealtimes, or eat one large daily meal.
Typical onset: 5–12 years
Lifespan Factors
The median lifespan for a Collie is 13 years. Key factors that influence longevity:
- MDR1 gene mutation (drug sensitivity)
- Collie eye anomaly
- progressive retinal atrophy
- dermatomyositis (breed-specific skin disease)
- bloat in deep-chested individuals
When Is a Collie Considered Senior?
Collies are generally considered senior at around 9 years of age. At this point, you should increase vet visits to twice yearly and watch for age-related health changes.
Check your Collie’s age in human years →