I have a sick 350 lb heifer calf I recieved about 3 weeks ago from local sale barn, along with 10 others. I worked them 2 days after recieving, with ml respitory, blackleg, wormed, given Excede, Ralgro implant and eartag. The rest are doing well on pasture and hand fed grain, but she has been slowly declining for about a week. It started with just being last one to come up and first to leave, then not even coming up at all. So after observing her up close I noticed that when she tried to poop, she had a hard time going, and when anything at all come out, it was all liquid,(dark colored, not light) nothing solid at all. Called the vet and he said give her another shot of excede, banamine, and 2 sulfa bolus pills which we did Tuesday. Now 2 days later, still no improvement. What really concerns me is she really isn't eating much at all. The watering hole where they drink has gotten pretty low(and nasty) because of drought, so I've been giving them fresh water. What should I do next?