Not saying it was a Mountain Lion but here in Western Kentucky we've got them. My brother has seen one on my neighbors farm, I've seen one in the outskirts of LBL and 2 of my neighbors have seen 1. One of my neighbors calves was attacked by one but fortanely the cat was run off before he killed it. Another farmer I go to church with had a calf attacked in a barn, again the calf survived the attack though, somehow. There was large cat tracks going out of the barn and the calf just had large scratches down his back and plugs pulled out of him. A different neighbor has caught a Lynx catching his chickens and I've seen one on the farm too, their big! So regardless what the wildlife law enforcement thinks their wrong or lieing, because they say we don't have them neither. One of the first two neighbors I mentioned said he seen them release some in Pennyrile State Forest but I don't know if I want to believe him or not, but their are at least a few out there.
Most likely it was coyotes or dogs but it might not be. Just examine the scene and keep a sharp watchful eye and a good gun near. Like someone else has mentioned you might want to fix you up some bait, but I wouldn't want somebody's pet to get mistaken for the varmit.
It sucks when you lose one that you think has it made. I lost one this last week, a nice large black bull calf that I thought was nursing but evidently wasn't getting enough and he ended up getting dehydrated in the 90 something degree heat and we were unable to save him. Therefore I'm having to watch the late calvers like 500, making sure they get plenty of milk and pushing them to the shade to stay with mama instead of out in the open sunny field. Hopefully I'll get some rain and finally a day out of the 90's.
Again sorry for your loss and I hope you find your predator or predators and make them pay.