Northwest Animal Hospital

Northwest Animal Hospital was designed from top to bottom with our patients in mind. We offer an open, airy lobby with three separate waiting areas, five modern exam rooms, including one with a window seat for cats.

Northwest Animal Hospital has a wonderful backyard for exercise of the dogs boarding. Our hospital is exceptionally clean and virtually odor-free.

For your convenience, Northwest Animal Hospital carries a wide variety of prescription foods, dental products, Gentle Leaders, and home care products for your pet.

Technology is changing the face of veterinary medicine, and we are committed to staying ahead of the curve. With specialized diagnostic tools like the VetScope and our ultrasound equipment, we’re state-of-the-art, as well as state of the heart.
  • Mon - Fri: 7:30am - 6pm
  • Sat: 7:30am - 1pm
  • Sun: Closed
  • Karen Diehl


    The most rewarding parts of my practice are improving the quality of life for animals and enhancing the relationship between animals and their human families."

    Dr. Karen Diehl has been an Associate Veterinarian at Northwest since 2000. Her practice includes general veterinary medicine, general surgery and general dentistry.

    Dr. Diehl graduated from The Ohio State University College of Veterinary Medicine as a member of Phi Zeta and the National Honor Society for Veterinary Medicine. Her Bachelor of Arts was granted by Ohio Wesleyan University.

    She has one very contrary  15 year-old cat named Arnie who talks all the time. He is top cat --- loves to be brushed while he eats.  Dr. Diehl lives in Dublin with her husband Jason and two sons, Alex and Brent, but she grew up in Zanesville.

    Her veterinary memberships include:

    • American Veterinary Medical Association
    • Columbus Academy of Veterinary Medicine
    • Ohio Veterinary Medical Association

  • Niki Hird

    Diplomate, American Board of Veterinary Practitioners (feline specialist)

    "Almost 40 years after receiving my V.M.D., I can't imagine a more rewarding life's work. I made my decision as a nine-year-old, because the dog I loved was dying. Knowing the loss, I find joy in the ever-increasing ways in which veterinarians can help pets and their people. Each year brings a deeper regard for the human-animal connection, one of life's true blessings."

    Dr. Hird's day is all about preventive care, medical needs and behavioral help.   Dr. Hird is a specialist in feline practice as a Diplomate of the American Board of Veterinary Practitioners.  Nonetheless, she takes equal pleasure in caring for BOTH dogs and cats.  She is a partner at Northwest with Dr. Kolb and serves as Director of Medicine.

    In practice since 1973, she graduated magna cum laude from the University of Pennsylvania School of Veterinary Medicine and became a Diplomate of the ABVP in 1996.

    Two pets make Dr. Hird's life quite wonderful and never dull. Batty is her charming orange 9 year-old tabby cat.  Excalibur is the 4 year-old German Shepherd who still possesses the energy of a puppy.  She loves to see Batty nestled into Excalibur's flank for a nap --- such a sweet moment.  Active Ex competes in agility and rally obedience with Dr. Hird.

    Grandchildren now outnumber pets. Felix, Madeline and Benjamin live in Boston.  A new granddaughter is on the way in Columbus.

    Her professional memberships include:

    • American Association of Feline Practitioners
    • American Board of Veterinary Practitioners 
    • American Veterinary Medical Association
    • American Veterinary Society of Animal Behavior
  • Tim Kolb


    "Pets model unconditional love. Pets help us have happier and healthier lives. To help pets and their families is an honor and a blessing for me."

    Dr. Kolb is both veterinarian and owner at Northwest Animal Hospital since 1991. He states that his primary responsibilies are: "savin' lives, stampin' out disease and surgicating." He throws in a rich sense of humor. While he particularly enjoys surgery, he simply loves being a veterinarian and the variety of accompany it. 

    In preparation for this career, he completed 3 years of undergraduate and 4 years of OSU's Veterinary School.  His formal education is enhanced by ongoing continuing education and reading.

    At home is Oyo, the Wonder Dog, an older Shepherd cross who followed him home from a weekend hike years back. Oyo thinks he is a lap dog, even though he weighs 65 pounds. "Every night he puts his chest and front end across my lap."

    Dr. Kolb is married to Denise for 34 years. His son Chris is also a veterinarian, practicing with him at the Banfield Easton Hospital. His younger son Goeff is an engineer. Dr.Kolb and Denise have two grandchildren, Reese and Ben, with a new granddaughter due to arrive in November.