Aloha! You're speaking to Dr. Michael Salkin I'm sorry that your question wasn't answered in a timely manner. It's very difficult for an online vet to discuss what might be occurring in a geriatric dog who is vomiting to the extent that Kane is vomiting. Vomiting isn't pathognomonic (specifically indicative) of any one disorder. Primary gastrointestinal diseases such as inflammatory bowel disease and malignancies in a geriatric Rottie need to be considered. Diseases outside the GI tract but which can cause vomiting include major organ dysfunctions such as pancreatitis, hepatitis, and chronic renal insufficiency but the list would exceed the space allotted to me in this venue. Please consider sedating Kane at home two hours prior to bringing him muzzled to his vet. You can pick up Acepromazine - a tranquilizer in the promazine class of drugs - at his vet hospital. Between the use of such a tranquilizer and a number of vet techs, Kane's vet should be able to examine him and perform diagnostics - blood/urine tests +/- X-rays or ultrasound. Additional tranquilization can be administered by needle if need be. Please respond with further questions or concerns if you wish.