You might also give an over the counter stool softner like Surfak wrapped in a treat for 4-5 days until things get regular. Bogus has to have one every day and has for the last month. He got so constipated and tried to pass a huge BM that his rectum started prolapsing...So after a trip to the Vet. this is what he told us to do and it softened up overnight. He had trouble with constipation for about 4-5 days and I just thought it would straighten out. He doesn't drink enough water. So we may have to do this from now on...Oh well, at least there are human things that they too can tolerate