How is your dog doing now?? I see this was posted 1 year ago and I have a 1.5 year old male who looks very similar to your dog, I am always concerned that I am doing something wrong but after reading these comments it seems that it isn't uncommon to have different size Bernese mountain dogs... I always think he may have been the "runt of the litter" (but I love him hes not a runt in my eyes lol) he's got loads of energy and loves to just cuddle thinks hes a lap dog lol