PTGS2 and osteoarthritis: It is a selective cyclo-oxygenase-2 (COX-2) inhibitor that has been widely used in osteoarthritis treatments in dogs (Monteiro-Steagall, Steagall & Lascelles, 2013) and other animals, such as horses (Goodrich & Nixon, 2006) and cats (Lascelles et al., 2007).