Cattle progressively waste away over a period of several months and die. Eat and drink well. Appear bright. Awkward stiff walk. No diarrhea. Vet thought it might be Johne's disease. We lost a bull and cow, both over 5 years old, and are wondering about a third animal, a cow, who has just delivered. Calf is healthy and thriving. Mom produces milk but is starting to get noticeably thin. Any ideas what is going on here? We do not vaccinate.