Wiktionary says...............
race (countable and uncountable; plural races)
1. A large group of people distinguished from others on the basis of a common heritage.
The Anglo-Saxon race
2. A large group of people distinguished from others on the basis of common, genetically linked, physical characteristics, such as skin colour or hair type.
IMO the first definition would imply that to describe the Welsh as sheep sh*ggers would be considered rascist.