When is it advisable to put Milo onto adult dry food?

He's now 6 months, but a man at one of our pet shops said, if you've got a male lab you want to keep him on the puppy food for as long as it says on the bag, as it could affect his growth if you don't.

But I've heard a lot of owners saying they change their dog over to adult food when they're 6 months old.

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- Zeus a 4 year old Boxer cross.
- Milo a 2 year old Labrador.