A long-acting flea and tick treatment from Merck Animal Health has earned approval for dogs at least six months old from the Food and Drug Administration (FDA). The approval of the new injectable treatment, called Bravecto Quantum, was announced by the federal agency on Thursday.It is the “first FDA-approved drug that protects dogs against fleas and ticks for 8 to 12 months,” according to the FDA.  Bravecto Quantum can be used for treating and preventing…