Authorities are investigating the mutilation and killing of three cows on a small ranch in northwestern Colorado.The two steers and one heifer were killed and had their genitals removed last week but there were no visible marks on the cattle indicating how they were killed, Moffat County sheriff's deputy Courtland Folks said. The state veterinarian has been asked to investigate."Possibly it could have been done for some type of worship with the organs," Folks said. "It's something that makes livestock owners uncomfortable."Rancher Jacque Osburn said the cattle, which had already been sold to a buyer, were in a pasture near the Craig-Moffat County Airport when they were killed. The animals were worth about $2,400."I guess if it's going to happen anytime, it's going to happen around Halloween," she said. "I hope it's not the start of something but you never know."Osburn, who has 200 head of cattle, has been telling other ranchers about what happened so they can watch their livestock.She said livestock mutilations were rampant in the area about 20 years ago but this was the first time any of her cattle have been hit. She has moved the calves in her herd to a different pasture."It's scary," she said. "People feel pretty immune from crime when out here, but we're not. It wasn't a good trick, and it sure as hell wasn't a treat."