North Ronaldsay(redirected from North Ronaldshay)
a breed of sheep kept on the island of North Ronaldsay, close to the Orkney Isles. It has an extraordinary susceptibility to primary copper poisoning. It ordinarily subsists on a diet of seaweed which has a low content of copper and molybdenum and a high content of zinc. Exposure to normal terrestrial herbage may cause fatal copper poisoning.