Doxy won't treat some of the more common TBDs found in greyhounds. Before Phene was diagnosed and treated for babesia, he too acted very strange (even for phene, who is one of the more "eccentric" greyhounds i've met) . Babesia isn't treated with doxy.One thing about TBDs and greyhounds...you probably know this already, but some of these dogs move around so much that they are exposed to lots of TBDs, even some that aren't native to his area. I had one hell of a time finding a vet to test phene for babesia because the offending brown tick doesn't live in Ontario, so if the doxy doesn't clear things up, it might be worth running the full TBD panel.