Kelly B. Tisher, DVM

Kelly B. Tisher, DVM is the current President and Treasurer of Littleton Equine Medical Center. He received his undergraduate degree at South Dakota State University where he served as  Student Body President. Dr. Tisher earned his Doctor of Veterinary Medicine from the University of Minnesota 1994. At Littleton Equine Medical Center, his focuses are Sports Medicine, Lameness and Magnetic Resonance Imaging (MRI). When not at the clinic, you will find him enjoying the great outdoors  with his daughter, Maggie, who tends to their dog, cats and chickens. Learn More

Scott Toppin, DVM, DABVP

Born in Metamora, Michigan, Dr. Toppin moved to Colorado in 1994, and joined the practice as an Intern that same year.  After the internship, he moved to Arizona and worked at Southwest Equine Hospital for four years.  During that time, he developed an interest in internal medicine and emergency surgery.  Dr. Toppin returned to Littleton Equine Medical Center in 1999, and has remained at the clinic since that time.

Dr. Toppin grew up with quarter horses that were supposed to race, but instead made really fast 4-H and field hunters.  He was a groom for a hunter/jumper trainer during high school and summers during college.

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Jessica Dunbar, DVM

Jessica Dunbar, DVM

Born in Rochester, Michigan, Dr. Dunbar grew up riding in the United States Pony Club and went on to compete in eventing through college. Dr. Dunbar completed her Bachelor of Science degree at the University of Illinois-Urbana-Champaign and her Doctor of Veterinary Medicine at the University of Illinois.

After graduating from the University of Illinois, Dr. Dunbar did a year long internship at Wisconsin Equine Clinic and Hospital then came to work here at Littleton Equine Medical Center in 2006. Dr. Dunbar’s areas of focus here at Littleton Equine are Dentistry and Chiropractic, but she enjoys all aspects of equine practice. Learn More

William French, DVM

Dr. French is a 5th generation Colorado native and grew up in Fort Collins. He started riding as a small child in both English and Western disciplines. After high school, he worked on guest ranches during summers and pursued a bachelor’s degree in Equine Science at Colorado State University.

While at Colorado State University, Dr. French competed on the horse judging team, was a teacher’s assistant for packing and outfitting, and completed research in Equine Reproduction. Dr. French was admitted to Colorado State University’s Veterinary School where his passion for the horse was furthered. After veterinary school, Dr. French completed his internship at Littleton Equine Medical Center, rotating through surgery, emergency and field services. Learn More

G. Marvin Beeman, DVM


Born in Highlands Ranch, Colorado, Dr. Beeman has been active in the equine world from early childhood to present.  He has greatly contributed to the education of equestrians across the United States and internationally.  An innovator in the equestrian world, Dr. Beeman has been presented with many awards.

He has been an equine practitioner for over 57 years, and his specialties include a variety of lameness and musculoskeletal issues.

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Charles D. Vail, DVM


 Born in Denver, Colorado, Dr. Vail has been a prominent figure in the Thoroughbred and Quarter Horse racing industry since 1958.  He has been with Littleton Equine Medical Center since 1960. Dr. Vail also served as the track veterinarian for Centennial Race Track from 1962-1963, and currently serves as a Colorado Racing Commissioner.

When not immersed in the equine world, he spends time with his wife, Jeannie, son & daughter, four grandchildren. Learn More

Terry D. Swanson, DVM


Dr. Swanson was raised on a cattle ranch 20 miles east of Chugwater, Wyoming.  This was the beginning of his respect and appreciation of horse, especially the equine athlete.

He has enjoyed many phases of equine veterinary medicine including surgery and reproduction but has honed his expertise, by demand and interest, to diagnosis and management of lameness of the performance horse.  He has attained wide respect not only locally but nationally as well.

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Lois Toll, DVM

Born in Denver, Colorado, Dr. Toll joined our practice as a Veterinary Assistant in 1981.  After going back to school, she became a Veterinarian in 1992. Dr Toll’s equine experience started with the 4H Pony Club.  Her personal experience includes; eventing, fox hunting, combined driving and mountain pack trips.  She also had the opportunity to work for a hunter/jumper trainer.

Dr. Toll prides herself on being a well rounded veterinarian, and enjoys the challenge of lameness and general practice here at Littleton Equine Medical Center.  Learn More

Ronald J. Streeter, DVM

Dr. Ronald Streeter (Ron) was born in Ponca City, Oklahoma, and raised on a nearby farm.

Dr. Streeter and his wife Kathi, who is also his assistant, enjoy general practice. They pride themselves in offering a sound and practical approach to ambulatory practice. They feel fortunate to be able to refer more difficult cases to the clinic for specialized care while remaining a part of their patient’s care. Learn More

David N. Lori, DVM, MBA

Dr. Lori was born and raised on a Morgan Horse Farm in Tunbridge, Vermont, and grew up 1 mile from the first Morgan horse in the breed’s history.  He attended high school in Scotland, and traveled much of Europe, before returning to the United States to attend college.

After completing his undergraduate degree, Dr. Lori explored the opportunity of medical school and worked as a research associate at Dartmouth Medical, along with taking classes.  It was at this time that Dr. Lori elected to pursue veterinary school. Learn More

Rebecca S. Dietz, DVM

Born in Bryan, Texas, Dr. Dietz is the youngest of three children. Shortly after her birth, the Dietz family moved to Roanoke, Virginia where her parents purchased a small animal clinic. Dr. Dietz spent her childhood watching her mother, examine and treat cats and dogs. It was these childhood experiences and her mother that inspired Dr. Dietz to pursue a career in veterinary medicine. Learn More

Shannon J. Murray, DVM, MS, DACVS

Dr. Murray grew up in New Hampshire. Most recently, she has moved from Rhinebeck, in the Hudson Valley of NY, to the Littleton area. She is very excited to explore her new ‘backyard’!

Dr. Murray earned her undergraduate degree at Pomona College in Claremont, CA where she majored in Neuroscience. She attended the University of California, Davis School of Veterinary Medicine. After earning her doctorate, she completed a rigorous surgical and medical internship at Rood and Riddle Equine Hospital in Lexington, KY, where she worked extensively with horses of all ages in the Thoroughbred industry. Dr. Murray then completed her residency in Equine Surgery at The Ohio State University, where she became skilled in all facets of equine surgery (elective and emergency), sports medicine and diagnostic imaging, including nuclear scintigraphy and CT. She particularly enjoys the challenges of gastrointestinal ‘colic’ surgery, and has a special interest in emergencies and critical care. Learn More

Jackie Christakos, DVM

Dr. Christakos grew up in southern Illinois and became passionate about horses early, beginning with riding lessons at age 10 and progressing to eventing at preliminary level before moving to Colorado in 2004 to begin her undergraduate education. Dr. Christakos completed her Bachelor of Science and Doctor of Veterinary Medicine degrees at Colorado State University. She then completed her internship at Littleton Equine Medical Center after graduation.

Dr. Christakos has remained with LEqMC since completion of her internship in June of 2013, working closely with Dr. Terry Swanson to further her skills in lameness and performance horse practice. She became certified in Equine Veterinary Medical Acupuncture in the spring of 2014.

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Kathleen Mullen, DVM, MS, DACVIM

Dr. Katie Mullen grew up in Evergreen and spent her summers on her family’s cattle ranch near Paonia. A good deal of her childhood was spent trying to catch her horse, a flea-bitten gray Arabian gelding. When convinced to be caught, he served as a sure-footed ranch horse or dressage show horse depending on the day.

Dr. Mullen spent many years taking advantage of the numerous educational opportunities at Cornell University. The long, cold, gray winters of Ithaca, NY served as the ideal location to study Animal Science (B.S. with Honors), Agricultural Economics (M.S.) and Veterinary Medicine (DVM and Large Animal Internal Medicine Residency). Before obtaining her veterinary degree, Dr. Mullen was as a trade economist in Washington, D.C. However, a yearning to be closer to the horses she had always loved, motivated her to apply to veterinary school.  Learn More

Sara Senn, DVM

Sara Senn, DVM is joining us from Colorado State University in Fort Collins, CO.  Dr. Senn is a Colorado native and attended CSU both for her undergraduate degree, her masters in science degree and her graduate degree. Dr. Senn grew up riding and showing Quarter Horses. Dr. Senn enjoys gardening and playing sports such as volleyball and softball.

Jackie Hill, DVM, DACVS-LA

Dr. Jackie Hill

Dr. Hill grew up riding horses in the hills of northern California and started competing in endurance rides in high school, which included finishing the Western States 100 miles endurance ride several times. Following her passion for all things equine, Dr. Hill earned her undergraduate degree and veterinary degree at the University of California, Davis in 2008 and 2012 respectively.

After vet school, Dr Hill completed an internship at LEqMC followed by a large animal fellowship at Oregon State University focusing on large animal medicine and surgery. She then went on to complete a large animal surgical residency at Cornell University where she worked on all large animals, from 2000-pound draft horses to 7-pound pot-bellied pigs! During her residency, she was trained in all facets of surgery including advanced orthopedics, upper airway surgery, regenerative medicine and emergency colic surgery.  Learn more

Lindsay Dykstra, DVM

Lindsay Dykstra

Originally from Connecticut, Dr. Lindsay Dykstra received her bachelors degree from New York University in business and economics. After graduation, she worked in finance in New York then attended Columbia University for a postbaccalaureate degree. Dr. Dykstra earned her DVM from Colorado State University in 2016, where she also enjoyed playing polo.

After receiving her doctorate, Dr. Dykstra completed a surgical and medical internship at Rood and Riddle Equine Hospital in Saratoga, NY where she worked primarily with Thoroughbred racehorses.

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Beth Graham-Williams, DVM

Dr. Beth Graham-Williams

Dr. Williams grew up in rural Northern California riding horses and working at a local barn.  She got her first horse at 16 and taught horseback riding through high school and college.  She attended Oregon State University for undergrad where she worked in a veterinary toxicology lab and completed a degree in zoology. She returned to California for veterinary school at UC Davis where she worked as a large animal ICU technician throughout her time there and completed an equine reproductive research study. Her interests are in general practice and internal medicine.  Learn more

Lindsay Deacon, DVM

Lindsay Deacon, DVM

Dr. Deacon grew up in West Chester, Pennsylvania where she started riding horses at age 8. She showed in the hunter divisions with her Thoroughbred and Irish Sport Horse before moving in 2010 to begin her undergraduate education at Virginia Tech. Dr. Deacon earned her DVM from Texas A&M in 2018, where she was the student chapter president of the Society for Theriogenology. Throughout her schooling, she has developed a strong interest in sports medicine and imaging in addition to integrative medicine and reproduction.

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Olivia Hegedus, DVM

Olivia Hegedus, DVM

Raised in Northwestern Ohio, Dr. Olivia Hegedus grew up riding in 4-H and local shows. By following along with her local veterinarian, Dr. Hegedus discovered her passion for animal healthcare. On a fastpitch softball scholarship, Dr. Hegedus received her bachelor’s degree in Biology with a minor in Chemistry from the University of Akron in Akron, Ohio.

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Garett Pearson, DVM

Garett Pearson, DVM

Dr. Garett Pearson comes to Colorado from Nova Scotia, Canada. Growing up in a farming community meant he was around horses from a young age. Dr. Pearson began riding as a teenager, in mostly english disciplines.  He received his bachelors degree in biology from the University of Prince Edward Island and his DVM from the Atlantic Veterinary College also at the University of Prince Edward Island. 

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