I appreciate the replies. I went to check on the cows about 6:30 yesterday evening, they all came to one end of the paddock because it was time to rotate and I noticed that calf wasn't with the other calves. I found it laying on the other end of the paddock and I was able to walk right up on it before it realized I was even there. After about an hour I was able to get cow and calf to lot to check temp. I immediately text my nephew who is a vet tech and text another vet nearby. Heard from nephew about 8:30 and he was going to have draxxin and banamine ready for me this morning. Checked calf before 6 this morning and it had died over night. He seemed to think pneumonia or something viral. We have had some pretty wild temp swings recently from 80 to over night lows of 40 along with rain, I'm thinking maybe that combo did it. He said none of the symptoms seem to go with a tick borne illness or perilla mint. I noticed no other symptoms besides lethargic and fever, Tuesday it was with the rest of the calves and seemed normal.