This is the 3rd time this has happened this year. I have a 450lb calf that is otherwise healthy but ca't get up. No other symptoms at all. I leave them hay in the evening and all cattle are fine. In the morning the calf is laying there and cant get up. These are big healthy calves this is happening to. I cant stand to watch another one waste away. They can stay alive for days upon days like this. Vet came out for one of them in December and found nothing.. any ideas. Big cows and bulls seem ok.