The invention describes a long-acting veterinary composition comprising at least one ketoprofen ester prodrug. The composition also comprises at least one veterinary acceptable triglyceride, and optionally, at least one preservative, and optionally, at least one additional veterinary acceptable excipient. The invention also describes a method of treating an animal for fever, pain, and/or inflammation by administering the long-acting composition comprising at least one ketoprofen ester prodrug to the animal in need thereof.