I have this hereford steer -(long yearling) that has been on corn, protein, vitamins & mineral for about 100 days now. I worked him up gradually to 1 bucket 2 times a day.This is the second time he has just decided to stop eating the corn all together. Smells it & walks away. I have 4 others that eat it all completely! Any ideas on what causes them to go off feed?? Also how can you tell when he is done feeding out and ready for slaughter? Any suggestions would be great! Thanks!