English Toy Spaniel

The defining health problem. The muzzle is shortened without a matching reduction in soft tissue, so the airway is crowded - narrow nostrils, an over-long soft palate, a collapsing windpipe. It produces noisy labored breathing, poor exercise tolerance and dangerous heat sensitivity, and severe cases are improved surgically. It also means anesthesia carries more risk than in a normal-muzzled dog, which matters for every procedure they will ever have.

The valve between the left chambers of the heart leaks, the heart works harder to compensate, and eventually it fails. It runs in the toy spaniels generally and appears earlier here than in most breeds. Annual listening from middle age catches it, and treatment is lifelong medication.

Large, prominent, shallow-set eyes are easily scratched, and corneal ulcers, dry eye and cataracts all appear in the breed. An ulcer is painful and can cost the eye if it is left - squinting, redness or discharge warrants a same-day appointment.

The kneecap slips out of its groove, causing a skipping gait and sometimes needing surgery. Common across toy breeds and checked at routine vet visits.

The domed skull sometimes leaves a soft spot that never fully closes, which is usually harmless on its own. Hydrocephalus - fluid accumulating on the brain - is the serious version and needs veterinary management.

A full set of teeth crammed into a shortened jaw means crowding, tartar and early loss. Daily brushing and regular professional cleanings under anesthesia are a recurring cost, and the anesthesia risk above makes each one a bigger decision than usual.