What physical feature did breeders develop to allow the Otterhound powerful swimming ability in icy water?

Answer

Webbed feet

The Otterhound's specialized equipment for arduous work in water included large, webbed feet, which provided the necessary propulsion for powerful swimming.

What physical feature did breeders develop to allow the Otterhound powerful swimming ability in icy water?
animalconservationstatusDogOtterhound