hmmm i really dont know but im sure someone else will. I would think tho, as with all things, you would start slow and work up to a bigger mountain (if it is ok..i dont know about if dogs should climb mountains)...maybe take him hiking on less strenuous trails slowly and then progress to bigger hills/mountains etc as he gets older and see how he does? Ask the vet in your area too because since he is in that geographical terrain im sure he/she will know if dogs can suffer from this too. What i would be really worried about at that age, if the work is strenuous, is him tearing something like ACL.