Liver problems can have very little or varied symptoms. Many times owners have asked me why their dog is vomiting at least once per day and is tired. Some may think the vomiting is normal to rid the body of unwanted stomach contents and the fatigue results from this vomiting. Well it is not unusual to find this in liver disease in dogs.
Liver illness can cause weight loss, increased urination, increased drinking and skin conditions. Sometimes lyme disease can cause liver illness and sometimes the treatment [doxy] can cause it. Even exercise such as a long run in high heat can cause liver damage.
The good news is that dogs have the innate ability to regenerate liver tissue with supplements, especially ones with milk thistle.