What it is
The thyroid is a small, butterfly-shaped gland in the neck. Its hormones act as the body's thermostat and pace-setter, telling cells how fast to burn energy. When they run low, everything idles: the heart beats a little slower, the skin renews itself more slowly, hair that falls out is not replaced, and the dog feels the cold.
In dogs it can arise when the immune system gradually destroys the gland or when the gland shrinks away, and it tends to appear in adulthood; in some puppies it is present from birth.
Because the change creeps in, it helps to compare: is your dog slower on the walk than last year, keener on the spot by the radiator, heavier while eating the same amount? Changes in coat and mood can be so gradual that you only see them when you look back at old photos.
Signs you may notice
- Sluggish, tires sooner
- Gains weight eating the same
- Seeks out warm spots
- Thin, dull coat
- Bald patches on flanks or tail
- Darker, thicker skin
A dog may become sluggish, tire sooner, gain weight without eating more and seek out warm spots. The coat can grow thin and dull, with bald patches on the flanks or tail, and the skin may thicken or darken.
When to see a vet
Book a visit if, over several weeks, your dog has slowed down, put on weight or lost coat without a clear reason.
This is general information, not veterinary advice. For your own dog's health, tests and treatment, see a vet.