These are from the Flying Dog record label's advertising campaign featuring their logo and the voices of various seiyuu who record for them.
First, Flying Dog put out a video without the names, featuring the dog barking and panting in the voice of each seiyuu. Then they put out the same video, but with each seiyuu saying their name after their turn. Here are both videos, with the names listed at the end of the post.
Here is the first video, with seiyuus unidentified:
Here is the second video, with each seiyuu saying their name. For example: "Seikai wa, Sakamoto Maaya deshita." ("The right answer was Sakamoto Maaya.")