"Mature dogs" refers to dogs that have reached adulthood or are fully grown. It means they are no longer puppies and have developed physically and mentally into their adult selves. Full definition
It's suitable for new puppies who don't have any training experience yet, as well as more mature dogs who have been bonding with their owners for most of their lives. (littledogtips.com)
Many problem behaviors we see in mature dogs develop from a lack of socialization and preventative work done early on. (ultimatepuppy.com)
Given that the protein content is high, at 27 %, I would recommend this food for mature dogs who are still active (exercising up to an hour a day). (animalso.com)