Ok, so I would bullet make more suffering than dogs and then kill?
Despite how skillfully you have butchered the English language, I think you're asking how shooting it would cause it to suffer more than hunting it with dogs. The answer to that is that it's extremely unlikely that you will kill one with a single shot because it requires an absolutely perfect angle, and even then it's not a sure thing. Instead, you will just give it a big ass open wound that will likely get infected and cause a long, slow, agonizing death.
I think that people don't really understand how absurdly tough these things are. They're huge walking tanks of muscle that have evolved to be successful at running into things as fast as they can head-first. Shooting it in the head isn't going to do shit.
I want to point out also that the process of hunting it with dogs only gives minor, superficial damage (if you can call that actual damage because of how thick their hides are) that heals quickly. Once the boar is immobile, you're able to quickly and relatively painlessly with a knife or gun with no risk of a ton of suffering.