Protein is important for older dogs. Even with exercise, older dogs tend to lose muscle mass, which means losses in protein stores. When your dog lost muscle tissue and proteins, this could damage the immune system and reduce the ability to respond to physical trauma and infectious agents.
When you change your senior dog’s food, it is a good idea to introduce it gradually. Add the new food slowly for seven to ten days, increasing the daily portion. Avoid sudden changes, as this can upset your dog’s stomach.