diarrhea and skeletal malformation. According to official website of the Chinese Zoological Society, pig liver is a high-protein and high-fat food. Eating too much will burden the digestive system of dogs and lead to indigestion symptoms such as diarrhea and vomiting. Pig liver is rich in vitamin A. If dogs eat it excessively for a long time, there will be symptoms of vitamin A poisoning, such as depilation, dry skin and skeletal deformity.