Yup, large breed nutro natural puppy would be excellent for him (any dog that will be over about 50lbs). I would switch him over gradually especially if he is currently having digestive problems. I would make the switch last about 3 weeks. I buy nutro natural large breed adult & senior but the prices are about te same for other formulas. A 20lb bag is approx $17.00 and the 45lb bags are about $26.00. Prices may vary with areas and stores so look around to find the best deal. Nutro also offers a frequent buyers plan, after you purchase 10 bags (you mail the upc's & receipts) they send you a coupon for a free bag of the same size! They also have a starter program where they will send you a booklet full of Nutro product coupons. You will like cleaning up after him a lot better than before as there area lot less stools. I have 3 large dogs (husky mix, GSD mix & rott) and when you walk through my yard it looks like I have cats using my yard as a potty!