From Longman Dictionary of Contemporary Englishudderud‧der /ˈʌdə $ -ər/ noun [countable] HBAthe part of a cow, female goat etc that hangs down between its back legs and that produces milk
Examples from the Corpus
udder• Good milk on low-cost forage; veal and reasonable beef; excellent udder.• The grunt had disappeared and her udder hung heavy and turgid between her legs.• Heads, safer, Home in on udders, under-groin hot flesh-tent, Hide eyes in muggy snugness.• Beneath her, the udder, once high and tight, drooped forlornly almost to the floor.• Also mares can be ticklish round the udder and resent the foal nuzzling around that area.• As he pushed the calf's head towards the udder he spat to rid himself of the polluting sight of birth.Origin udder Old English uder 