I generally don't buy feed from tractor supply, BUT they have a good calf milk replacer. Compare the label and see if it ads up to manapro who usually have good products. I have raised hundreds of calves and never had one picky about the brand of milk replacer. Are you sure the temperature is not too hot? Or ice cold? Is the milk replacer fresh and not been sitting too long and stale?
We monitor the temperature with a thermometer and the milk replacer is fresh. It's strange because she sucks the electrolytes right down when we put them in the bottle, and we even milked the mom a little and she liked that. She will drink the replacer when we hold her head up and "force feed" her, but you can tell she doesn't like it much and she drinks it very slow. The mom is wild and MEAN, and even getting her through the squeeze to milk her is a challenge. The calf is premature, got pneumonia, ear infection in both ears, and an umbilical cord infection. Today is day six and she seems to be stronger. We've tried putting her back with the mom but she doesn't have the energy to chase her around and nurse, and it doesn't seem like she gets enough milk out of her.