Regional Institute for Veterinary Emergencies & Referrals

2132 Amnicola Hwy Chattanooga, TN 37406

Phone : 423-698-4612

Fax : 423-622-8145

Our Team

Dr. Sallye Gregg, DVM, Residency Trained; Hospital Director


Our Veterinarians

Sallye Gregg, DVM, graduated in 1980 with a BS in Animal Science from the University of Tennessee Knoxville. She continued at The University of Tennessee College of Veterinary Medicine where she received her Doctor of Veterinary Medicine in 1983. Dr. Gregg spent the next seventeen years working and managing a full service private practice in Cleveland, Tn. In 2000 she moved with her family to Charleston, South Carolina where she served as the Medical Director for the Greater Charleston Emergency Clinic, and Mt. Pleasant Emergency Clinic. From 2002-2006 she completed a residency in Emergency and Critical Care while serving as the Director of the Emergency Department at North Carolina State University College of Veterinary Medicine. Dr. Gregg is currently serving as the Hospital Director of the Regional Institute for Veterinary Emergencies & Referrals (RIVER). Dr. Gregg lives in Ooltewah with her husband Steve, and has two sons Dustin and Will. When she's not at the hospital, you can find her riding her Harley-Davidson, reading, or doing cross-stitch.




Mark Bohling, DVM, PhD, DACVS, Chief of Surgery


Our Veterinarians

Dr. Bohling is a 1986 graduate of the School of Veterinary Medicine, University of California, Davis. After working as a food animal veterinarian for six years, he began working in small animal general and emergency practice in 1992. In 2004 he completed residency training in small animal surgery at Auburn University, and has been board certified since 2006. In 2007 he finished a PhD, also at Auburn, where his dissertation work focused on comparative wound healing, specifically regarding how wound healing in cats differs from wound healing in dogs. From 2005 to 2012 he served on the faculty at the University of Tennessee College of Veterinary Medicine. Dr. Bohling joined the Surgery Department at RIVER in November 2013 as a general surgeon. He considers himself a general veterinary surgeon, ready to accept just about any surgical challenge that comes to RIVER. Within the broad field of general surgery he maintains special interests in wound management, reconstructive and oncologic surgery, fracture repair, and surgery of exotic species.




D.J. Krahwinkle, DVM, DACECC, DACVS, DACVA


Dr. Krahwinkle completed his undergraduate studies at The University of Kentucky (1960) and Western Kentucky University (1961-62). He attended Auburn University College of Veterinary Medicine, where he graduated Valedictorian of his class in 1966. He continued his education at Michigan State University with a Master’s Degree in 1973. He is triple boarded in small animal Emergency and Critical Care, Anesthesia, and Surgery.


Dr. Krahwinkle taught at Michigan State University College of Veterinary Medicine as an Assistant Professor of Anesthesiology and Surgery from 1969-75. He then taught at The University of Tennessee College of Veterinary Medicine as a Professor and Head of Small Animal Clinical Sciences from 1975-2002 and a Professor of Surgery from 2002-present. He is a diplomate of the American College of Veterinary Surgeons, the American College of Veterinary Anesthesiologists, and a diplomate of the American College of Veterinary Emergency and Critical Care. He served as the President of the Tennessee Veterinary Medical Association from 1987-88, the President of the American Association of Veterinary Clinicians in 1998, and was a member of the AVMA House of Delegates from 1999-2003. He visits R.I.V.E.R. every other Thursday to perform soft tissue surgeries.




P.K. Hendrix, DVM, PhD, DACVA


Our Veterinarians

Dr. Hendrix is a Louisiana native. She graduated from the Louisiana State University School of Veterinary Medicine and practiced for a short time in a mixed animal practice in south Louisiana. She completed her anesthesiology residency and PhD from the University of Minnesota, remaining on faculty at the University of Minnesota for a total of 12 yrs. In 2001, she and her husband, Mitch, moved to Mississippi where she was a faculty member at the Mississippi State College of Veterinary Medicine until 2008, when they relocated to the Nashville, TN, area. In Nashville, she was a clinician at Nashville Veterinary Specialists until December 2013, when she and Mitch decided to move to the beautiful Chattanooga area where she is now a member of the RIVER team!




Tim Crowe,DVM, DACVS, DACVECC,NREMT-I, EMS-I


Our Veterinarians

Dr. Crowe received his DVM in 1972 at Iowa State University. He completed a rotating internship in 1973 at Colorado State University, followed by a 3-year surgical residency at The Ohio State University in 1976. He received board certification in surgery in 1980. He became a founding member of the American College of Veterinary Emergency and Critical Care in 1989. Dr. Crowe is an Emeritus Diplomate of the American College of Veterinary Surgeons and is a Charter Diplomate of the American College of Veterinary Emergency and Critical Care. He was the first President of the VECC and last President of VCCS and instrumental in bringing emergency care and critical care into one organization.


A founder of ACVEC, he received the VECCS Zaslow Award for his pioneering, teaching, leadership and innovation in veterinary emergency and critical care in 2004, and was awarded Fellow status in the American College of Critical Care Medicine in 2007. Dr. Crowe is an active certified firefighter and licensed medic. He is active on the Program Committee of the Society of Critical Care Medicine, and was recently awarded a President’s Citation for significant contributions in critical care in 2014. Dr. Crowe is a member of the American College of Hyperbaric Medicine, and has published more than 500 refereed and non-refereed articles and proceedings and has given over 1000 invited lectures worldwide.


Dr. Crowe is a father of 2 and grandfather of 6. He has been married to his best friend, Deb, for 44 years. His hobbies include playing the guitar and harmonica for his church’s Praise Team and for Kairos Prison Ministries.




Cheryl Braswell, DVM, DACVECC, CHT-V, Chief of Emergency and Critical Care


Cheryl Braswell

Dr. Braswell has been practicing veterinary medicine for 36 years, graduating from the University of Georgia in 1979. She originally started her career as an associate small animal general practitioner. After 5 years she established her own business and continued in general practice for the next 17 years. Having retired from general practice in 2005, she pursued a residency in small animal emergency and critical care. In addition to her diplomate status in the American College of Veterinary Emergency and Critical Care (2012), Dr. Braswell is also a Certified Veterinary Hyperbaric Technologist (2013) and is currently seeking certification in veterinary pain management.

Dr. Braswell served as a Clinical Associate Professor for the College of Veterinary Medicine at Western University in Pomona, California before moving back to the Tennessee area in 2015. She especially enjoys teaching in the clinical setting, routinely supervising externs and interns. Most recently, Dr. Braswell has developed a sincere passion for care of veterinary patients with life-limiting diagnoses. She believes there is a place for palliative medicine and hospice care of veterinary patients seen in the emergent setting.

Dr. Braswell maintains active participation in the community. Historically, her focus has been on providing wellness care for pets of the homeless as well as contributing support of the care of animals in local shelters. She enjoys gardening, performance competition with her canine companion and family. She has two daughters, Kathryn, who has recently graduated and practices in the field of oriental medicine (human), and Veronica, who is completing her second year of veterinary school.




Elizabeth Shull, DVM, DACVIM-Neurology, DACVB


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Dr. Elizabeth Shull is Board Certified in Veterinary Neurology (1986) and Behavior (Charter Diplomate 1993). She received her Doctor of Veterinary Medicine
from the University of Tennessee and then completed an internship at Michigan State University. She then followed with a residency in neurology and neurosurgery at the University of Tennessee. 
Dr. Shull was a faculty member at the University of Tennessee, Knoxville for 16 years before starting her private practice in Knoxville in 1999.




Melissa Mays, DVM


Our Veterinarians

Dr. Melissa Mays graduated from the University of West Florida with honors in 2006 with a BA in Exercise Physiology with an emphasis on Pre-Professional Biology. She continued her education at The University of Florida College of Veterinary Medicine where she received her Doctor of Veterinary Medicine in 2009. While at UF CVM she received various awards and scholarships including the Florida Veterinary Medical Association Student Excellence Award and the American Association of Feline Practitioners Award. Dr. Mays then continued to successfully complete a 1-year rotating small animal internship at VCA Aurora and VCA Berwyn Animal Hospitals in Chicago, IL. She recently moved to Chattanooga, TN with her three dogs and enjoys paddle boarding, eating out and the Florida Gators.




Kaihla Parker, DVM


Our Veterinarians

Dr. Kaihla Dailey Parker graduated from the University of Tennessee, College of Veterinary Medicine in 2010 and proceeded to Ventura, CA for a rotating internship focusing in emergency and critical care. She then came back to TN where she entered general practice for about a year before realizing that emergency and critical care was her true passion. She has been with RIVER since June 2012 and really loves working in the emergency department. Dr. Parker has always had a passion for teaching and is our veterinary student externship coordinator. She facilitates students coming through RIVER for 2 week periods as part of their last clinical year in school before graduation. Dr. Parker also teams up with ER department head, Becky Howell, to lead the technician training program. They organize meetings, training sessions, and wet labs with the staff to keep everyone excited while advancing their skills in the veterinary profession. 



In her spare time, Dr. Parker enjoys spending time with her husband, Bobby and step-daughter, Andi as well as their Blue Heeler, Birdie. They like camping, hiking, playing kickball with the CSL, and traveling. Dr. Parker also enjoys playing the piano, acting in plays and commercials, performing improvisational comedy, reading, cross-stitching, and gardening. Her guilty pleasures are playing her "old school" Nintendo-64 legend of Zelda, watching Star Wars, and eating Reese's Pieces. 




Livi Clagett, DVM


Livi Clagett

Dr. Clagett is a small animal veterinarian who comes to us from Colorado State University, where she completed both her undergraduate degree in Biomedical Sciences and her Doctorate of Veterinary Medicine. She has a special interest in emergency medicine, exotic pets, and zoo mammals and plans on completing a residency in zoological medicine. She will be staying with R.I.V.E.R. for an additional year after her internship to gain more experience in emergency medicine before pursing her residency.


Outside of the veterinary world, Dr. Clagett enjoys outdoor activities with her two dogs. She grew up in a military family and as such, loves to travel whenever she gets the chance. She absolutely loves Dachshunds, Pugs, and Rottweilers, along with any kind of exotic pet that walks through the door.




Tim Ericksen, DVM, Intern




Andrew Kiser, DVM, Intern




Teresa Schumacher, DVM, Intern




Cassie Lord, DVM, Intern




Chris Perry, DVM, Intern


Dr. Christopher Perry graduated magna cum laude from Valdosta State University with his Bachelor’s Degree in Biology in 2011 before completing his Doctorate of Veterinary Medicine at the University of Georgia in 2015. Of the many interests that Dr. Perry has within veterinary medicine, he particularly enjoys emergency medicine, surgery, and comparative medicine. Dr. Perry is a member of the American Veterinary Medical Association, the Veterinary Emergency and Critical Care Society, and the Hamilton County Veterinary Medical Association. It is Dr. Perry's goal serve clients and their pets in the greater Chattanooga area by maintaining the quality of care that RIVER is known for providing. 



When not practicing medicine, Dr. Perry is most likely to be found hiking in the surrounding Tennessee and Georgia mountains with his Border Collie mix named Zoe. Dr. Perry is an avid traveler and enjoys learning of new cultures. In fact, his love for travel and medicine led him to study veterinary medicine abroad in Brazil while obtaining his DVM degree.