There could be many possible reasons why your Rott is not eating and seems drowsy. These are often non-specific signs that can indicate disease. He should have an examination by a Veterinarian to better ensure that he is healthy and attempt to determine what is causing this behavior. Heart disease for example is a fairly common disease in this breed and often goes undetected at home if only causing mild signs such as decreased activity, tiredness, appetite decrease. During an examination we will thoroughly review his history, listen to his heart and lungs, and thoroughly examine other body systems as well. If indicated based on history and examination, diagnostic testing may be recommended as well. Please contact us at your earliest convenience to schedule an appointment. Call us at 813 988-1189.