A federal judge’s ruling will keep a pet food blogger out of the dog house, at least for now.Finding the bulk of her blog posts were based in opinion, U.S. District Judge Edmond E. Chang dismissed most of the defamation claims brought by Markham-based Evanger’s Cat and Dog Food Co. against Susan Thixton and her website, truthaboutpetfood.com.Thixton’s statements were clearly expressions of opinion and not actionable facts, Chang found. And those personal beliefs were backed by evidence.“In essence …