I have an 7 week old brangus bull calf that was the first born of twins (both bulls.) He received colostrum from mama before he was orphaned and has been very vigorous and healthy bottle feeder and grain nibbler. However, the last two weeks he has had problems defecating. I took him to the vet and he was diagnosed with a bacterial infection,given antibiotics and sent home. Now, when he nurses, he consumes approximately a 1.5 gallons of medicated milk replacer then exhibits signs of gastrointestinal distress (kicking/biting at stomach, extending back legs or just lying down curled up. Very similar to colic in a horse.) He refuses to eat for about a day and a half, then acts as if he is ok, wants to nurse seems to feel good. However, when he eats the cycle starts again. He is urinating, but I haven't seen any signs of fecal material. He is losing weight rapidly. Any suggestions?? Thanks in advance for any help out there!!! P.S. I have given him microbes in paste form and B vitamin injections.