It is not necessarily abnormal for dogs not to defecate for four or five days after the recovery of pancreatitis. However, if the dog has constipation symptoms, such as forced defecation or dry feces, it may be due to the following reasons:

1. Dietary problems: insufficient cellulose content in the dog's diet, insufficient drinking water, or too fine food may lead to constipation.

2. Insufficient exercise: If the dog lacks exercise, intestinal peristalsis may slow down, leading to constipation.

3. Older dogs: The intestinal function of older dogs may be weakened, leading to constipation.

If the dog has constipation symptoms, you can try to adjust the diet, increase the amount of water and exercise, or use laxatives or dietary fiber to help the dog defecate at the suggestion of the veterinarian. If the dog has severe constipation symptoms, such as defecation but unable to defecate, or vomiting, abdominal pain and other symptoms, it should seek medical attention immediately.