Become one with the bark...gunga...gunga la gunga...
I noticed the same thing on the Glen Beck show when it first came on. In fact I would ask Mr G if he heard a dog.
I have finally decided that it is a sound effect that they use when they are putting up certain info to get you to look at the screen. Kind of like the “whoosh” sound they use for certain captions.
Personally, I find it very annoying.
fox-hunting dog?