I have an 18month Old English Mastiff. He uses his hunting instinct to the extreme, any smell good or bad he has got to explore it even if it is hundreds of yards away on the other side of the field. This is frustrating when he will not come back when called even if treats are on offer. Then he will lock on to the smell frantically, either until he has eaten the source of it or until it is removed. He will fight me on the lead until he can get to it and no extent of persuasion will entice him away until he is satisfied.As you can imagine he is extremely difficult to shift as he weighs over 10stone he has nearly dragged me under a hedge before to get to where he wants to be. Generally he is good on a lead and has a wonderful gentle nature,but this means I am constantly on the look out far any sources of rubbish he may want to get into and I am starting to get reluctant to let him off because I don't know where he will end up.
have you tried the gentle leader or halti for your walks? That will give you more control over your dog in the meantime.
If you have a fenced yard I would recommend to spend some time in there with your dog and practice the command come. He will need to be conditioned so that he comes 100% reliably. It is possible to achieve, but you need to work on it for a while. Never call him to you when you can't reinforce the command and he can get away with ignoring you. Have him on a leash and tuck lightly on it if he ignores your command. Always follow it through. Don't just call "come" and then let him get away with not coming. He will just learn to ignore that command. If he is already ignoring it invent a new commands ("back to me" "return" etc) and practice that with treats. If he is not into treats you could lure him back to you with something that smells good to him. Always make coming back to you a positive experience. If you only call him back to finish a walk, play session or to drag him away from smells he will resent coming back to you. Call him to you often during play sessions and make a big fuss over him when he comes.
