- Give us a call today at 281-492-6100 . Dr. Thomas McGowan and the staff at Green Trails Animal Clinic, are passionate about providing their patients with the best quality care possible. The team specializes in routine care, pet surgery, and internal medicine. Our office has on site laboratory, radiologist, and pathologists in order to diagnose and treat specific patients needs. The office serves the surrounding towns of Green Trails, Cinco Ranch, and Katy.