Troubled habits..Please Help!

[the_beagleteers]

I have a 3 year old beagle that has some troubling tendencies and my wife and I cannot seem to break him out of it...

Whenever we take him out for a walk, if he sees a cat or a small critter he starts pulling wildly, and howling and nothing seems to snap him out of it.

I try calling his attention, standing in front of him, break his concentration with a treat, but none of that works at all.

Any experience or suggestions would be greatly appreciated!