Try a different feed, early in the game so switching feed on him now will not be a big deal. I had a calf that we tried several feeds on, he would not eat any, i mixed them all together just to get rid of them, he ate it like he was starving. One was more of a dry mix the other was wet (molasses) and the other was just a commercial beef feed. Found that by mixing the dryer feed with the wetter feed we hit a range he liked.
Have also had feed with bad fat in it, when you opened the bag it had an odd smell, one calf did not care and ate it the other did not touch it, took it back and got a different lot# and they ate it fine.
I have used just sweet cob to start, if they eat that well, then start adding the desired feed to it slowly, so they adjust to it.
Feeding them is always a challenge, it can be the hardest part but it can be rewarding as well, if you get a difficult calf to eat and get on track, it seems all is right with the world, good luck and don't get frustrated.
I really don't like it when they do not list the type of grains on the bag, to me it allows them to change the mix as long as they keep the nutrition levels the same. Had a feed guy tell me you could mix sawdust, kitchen grease and paper to get the right nutritional value, it just would not be digestible, see China and Baby formula.
