Dog Bowl Movements after Surgery

My dog had orthopedic surgery 3 weeks ago and every since he is only pooping every 4-5 days is that normal?

Hello - it's not necessarily normal, but may be explainable, depending on your dogs' particular situation.  If a dog is straining unproductively to deafecate, uncomfortable around their abdomen, licking the anus raw, squatting / straining to poo but unable to, lying with their front end down but bum in the air, eating less or licking their flanks abnormally, then your vet should be notified / triage the case immediately.  You don't say what your dogs' surgery was for but if, for example, it was hip / spinal / knee or abdominal surgery (or testicular!) then it might be that the patient needs support to stand in order to deafecate comfortably and so is 'saving it up' until desperate; this can overstretch the final stages of the digestive tract so would be better addressed sooner rather than later by speaking to your veterinary team.  Anaesthetics do slow the progress of food through the body and often involve a 24 - hour window where no food was given, so this could be a contributory factor, but three weeks is a long time to still be showing signs.  I wonder whether the surgery may have affected the type of food being given, which of course in turn impacts the faeces, or whether it could have introduced pain, affecting the quantity eaten.  Sometimes, an operation can trigger other pre-existing disease eg pancreatitis or hypothyroidism, which can come with a low appetite.   Any of these possibilities - and Im sure there are more - should be picked up by your vet, who has more context about the surgery than I do. It would be a good idea to run this case by them as soon as you can.