Our Practice

Tustana Animal Hospital is dedicated to consistently provide the highest quality of compassionate veterinary care and offer an exceptional experience to our clients and their pets. Our defining quality is the passion we bring to enhance the lives of our patients and their owners whilst fostering the human-animal bond. We believe in partnering with our clients, through preventative care, education and the highest quality in veterinary medicine to allow our patients to live longer, happier lives. ​We also serve Santa Ana, Orange, Villa Park, Irvine and Anaheim ( North Orange County).

  • Dr. John Coleing


    Dr. Coleing was born and raised in the rolling countryside of England, he has always been passionate about animals and knew from a young age he wanted to be a veterinarian. After graduating from the prestigious Royal Veterinary College in 2007, Dr. Coleing practiced small animal medicine in England before deciding to move to the sunnier climes of the US in 2009.

    Dr. Coleing has an unwavering compassion and devotion to helping pets live happier, longer lives and a commitment to partnering with our clients to help make the best decisions for the health of their furry family members.

    Dr. Coleing has loved to combine his love of traveling with wildlife conservation. He has spent time researching monkeys in Sri Lanka and saving wild animals in South Africa. From lassoing giraffes to wrestling pythons and bottle feeding orphaned hyenas.

    Dr. Coleing brings that same passion in everything he does and cannot wait to meet each and every one of you and your four-legged friends.

  • Dr. Rene McCarthy


    I was born and raised in Trabuco Canyon, and my mom actually graduated HS from Tustin HS, right across the street from Tustana. Her maiden name is Serrano, and her ancestors were one of the founding families of El Toro, now called Lake Forest. I knew from as far back as I can remember that I wanted to be a veterinarian. I was raised with dogs, cats, turkeys, rabbits, sheep and chickens, and had a horse growing up. I attended Cal Poly, San Luis Obispo and graduated in 1995 with a B.S. in Animal Science, minoring in English and Philosophy. I then attended UC Davis School of Veterinary Medicine, graduating in 1999.

    I love being a veterinarian, even after 22 years. I love helping animals, meeting their owners and the fact that  there are opportunities to learn something new every day. All my fur kids are rescues, I definitely favor Chihuahuas and black cats, but also have 2 squirrels ? that I bottle fed and are unable to be released.

    I love traveling, reading and am married to the most wonderful man I’ve ever met, my boyfriend from high school. We found each other through Facebook about 7 years ago and the rest is history.

  • Peggy McDill


    Peggy has been our groomer at Tustana for over 25 years. She offers your pets a true “spa” day with special treatments and personal attention.
    Her background includes showing dogs with a specialty in poodles. Peggy is available on Tuesday and Thursday.