Cattle and horses have body temperatures higher than humans do. They are VERY cold tolerant animals. The biggest risk with livestock is WET, COLD WIND. As long as the animal can stay reasonably dry and out of cold, wet wind, they will be ok. They need some kind of windbreak (loafing shed, shrubs, tree cover, etc.) in those "bad" conditions. New born calves should always have protection from real cold until they are up and running good.
Most important thing IMO is to provide plenty of protein rich hay (supplemented by range cubes as needed) and good water when the weather is cold and bad. Digestion of hay creates body heat. They should have access to all the hay they want to eat 24/7.
In our area, when IMO the outside weather is darn too nasty for me to be out in it, some of our livestock will be in pasture or paddock grazing or standing with backside to wind or blowing rain, even if their loafing shed is close to them. Others will be in and out of the shed.
If one's cattle are usually kept in a "warmer protected area" (e.g., shed or barn) their normal winter coats will not grow out as soon and as thick. Leaving them outside (with access to a shed if they want to use it) allows nature to grow them a heaver coat of hair for winter. (For example: Hair coats of Yaks, or the Ice Age Mastadon's. Alaskan Huskies vs. Smooth short coats of Southern hemisphere dogs)
