2. It is the first sign of illness
When your puppy or a dog is ill or not feeling well, they are prone to becoming passive and sleepy, and they lose their appetite. This doesn’t necessarily mean they are suffering a serious illness, as they might have just hurt themselves while running or playing. Pay attention to their movements and check if they are walking properly.
While it can just be a sign of a minor health issue, loss of appetite can also indicate serious illnesses such as kidney failure, dental disease, strong pain, liver problems and even cancer. So, make sure you take your dog to the vet and do some tests to find out the cause.