Guinness, our almost-4-month-old Australian Shephard, gained 10 lbs. from one vet visit to the next (about a month apart). He's not overweight, but because I WAS giving him a bath once a week, his skin is a little dry. The vet, who we've only seen twice, suggested we switch his food from Nutro to Science Diet. I've heard of vets pushing certain products, so this naturally turned me off to returning to her for his 3rd visit. He is eating Nutro Ultra which is supposed to be high in protein including salmon to help with skin, coat, muscle development, etc. I think we're fine leaving him with the food we're already giving him, but the vet mentioned Nutro being high in sodium. So, DOES ANYBODY KNOW WHICH DOG FOOD BRAND IS BEST BETWEEN NUTRO OR SCIENCE DIET?? Any experiences or stories about either?