Complex sentence: The Swedish Vallhund is responsive and even-tempered with most people, but they can be wary of strangers and should be properly socialized and trained as a puppy as to avoid over-protective behavior as an adult.
Split into simpler sentences: The Swedish Vallhund is responsive and even-tempered with most people. But they can be wary of strangers and should be properly socialized and trained as a puppy as to avoid over-protective behavior as an adult.