[Draco]

Have you talked to the neighbor yet? How long have they been there? Do they escape the yard ever?
I think you should definitely talk and express your concern for your cats to your new neighbor before calling animal control. Maybe you'll get a chance to get a better look at the dogs. The neighbor deserves some kind of warning, like telling him about the law if your area does limit a certain amount of dogs or the tethering. Instead of them just being slapped with a fine or having the dogs being taken away and most likely put down. Just saying if you feel the need to report them do give them a chance to find the dogs another home, or a rescue.