The red comes from red angus. The BueLingo Society accepts both red and black as primary colors for buelingos. The reason why there is red is because when we started raising buelingos, we bred a buelingo bull to bunch of angus (red and black), herefords and mixture of other breeds. All the cows in the picture are 5th generation cows, which means that they are purebreed buelingos now. Alot of farmers will start by breeding a buelingo bull to a mixture of cows, becuase the belt trait is so dominant that the cows will more and likely produce a belted calf even if they aren't belted themselves. I hope that helps answer your question.
The BueLingo Society has a website that you can check out www.buelingo.com
, it kind of describes the specifications for buelingo cattle.