Meet our amazing veterinarians!
Dr. Marshall Kohr
Dr. Kohr's Bio
Marshall grew up in Millersville, Pennsylvania, in agriculturally-based Amish Country. In 1985, he started veterinary school at Colorado State University, graduating along with his classmate and future business partner Dr. Darren Lynde in 1989. While Dr. Lynde returned to his hometown of Gillette, Dr. Kohr practiced in a livestock clinic in Bridgeport, Nebraska. Two years later, he reconnected with Dr. Lynde and moved to Gillette, where the pair started their own practice in the spring of 1991.
Professionally, Dr. Kohr is interested in the diagnosis and treatment of equine lameness. He also enjoys the challenge of equine reproduction. He is proud of all the different perspectives, skills, and personalities the staff of the Animal Medical Center bring and is always excited to come work with such a great group of people.
Marshall is married to his wonderful wife, Lynn, who Dr. Kohr says is one of the best horsemen in the Rocky Mountain region. He also has three children, two in High School and one in Junior High. He loves watching his wife and kids compete in barrel racing, and attending his kids’ hockey, basketball, and other sporting events.
Dr. Kohr serves in the Wyoming Army National Guard as a Colonel!
Dr. Nate Zieman
Dr. Zieman's Bio
Nate grew up in Sheyenne, North Dakota, where he enjoyed playing sports and participating in rodeos. Before moving to this area, he worked in a mobile bovine clinic for two years.
At home, Dr. Zieman lives with his wife Tracy, their 7-year-old Koy, 4-year-old Tyler, and 3-year-old twins, Trey and Kynlee. When time allows between work and family, he enjoys team roping and hunting.
Dr. Brad Powell
Dr. Powell's Bio
Brad grew up in Texas and attended Abilene Christian University to obtain his Bachelor’s degree in Animal Science. He went to Texas A&M’s College of Veterinary Medicine for his veterinary degree, and worked at a practice in Abilene for two years after graduation. In the fall of 1999, he joined the team at the Animal Medical Center as an Associate Veterinarian.
Dr. Powell enjoys the challenge of jumping from one species to another as a mixed-animal practitioner. He’s especially passionate about equine lameness and equine dentistry cases.
Brad has been married to his wife Melissa for 26 years. Together, they have three children: Kolten, who graduated from the University of Wyoming and serves along with his wife Katie, as a campus minister at the University, Brenna, a student at the University of Wyoming, and Mason, a high school student who enjoys playing hockey and baseball.
Dr. Powell’s interests outside of veterinary medicine include fly fishing, hunting, reading great books, coaching youth sports, and learning about history. Brad considers himself a life-long student and learner.
Dr. Darren Lynde
Dr. Lynde's Bio
Before deciding to become a veterinarian, Dr. Lynde had a few professions in mind: working with people, working in the medical field, or caring for animals. He then realized that being a veterinarian combined all three!
Darren’s family has lived in the Gillette area since the early
Every day, Darren heads to the clinic excited, because he knows that every day is different. He especially likes internal medicine cases, and also is proud of the recent advances in dental care that allow him to stop undetected pain and infections.
At home, Dr. Lynde lives with his wife of 19 years, Kim. They have two children: Garrett, 15, who is possibly the biggest Broncos fan in Gillette, and 12-year-old Lauren, who is passionate about dance. The family has several pets as well—Stella is a 9-year-old terrier mix, and Milkshake is a 2-year-old cat that was found abandoned under
In his spare time, Darren enjoys fly fishing, ice fishing, and trolling, which he started very young with his father and grandfather. He also enjoys reading history and current news.
Dr. Diane Ernst
Associate Veterinarian (part-time)
Dr. Ernst's Bio
Diane attended veterinary school at Washington State University. After practicing in Glasgow, Montana, she joined the Peace Corps for three years. After that, she practiced in Belt, Montana before returning to her hometown of Gillette. She joined the team here at the Animal Medical Center in September of 1996.
As a vet, Dr. Ernst loves working with kittens and puppies and helping to make their first visits not so scary. She also enjoys offering training and care tips to owners to ward off potential behavior problems.
In her free time, Diane enjoys reading, riding horses, singing in the community choir, and helping out on her friend’s ranch. She also has two dogs of her own, both adopted from the local shelter, Border Collies: Jess, a ball fanatic, was adopted from a local shelter, and Dodge, who is gradually coming out of his shell. Her 16-year-old kitty, Boots, does what he wants when he wants!
Dr. Rachel Young
Dr. Young's Bio
Rachel spent four summers working at a guest ranch in the Big Horn Mountains outside of Buffalo, Wyoming. She absolutely loved the area, and started to look for a veterinary clinic nearby. In July of 2013, she started at the Animal Medical Center. She especially loves meeting people and their pets, and is constantly rewarded when she hears back from clients that their sick pet is doing well again.
Outside of work, Dr. Young enjoys horseback riding and hiking in the mountains, which she often does with her horse, Rusty. She also loves photography and scrapbooking, and likes to read and write when the weather isn’t agreeable.
Dr. Susan Lucas
Dr. Lucas' Bio
After two years of pre-veterinary medicine studies at North Dakota State University in Fargo, Dr. Lucas was accepted into veterinary school at Kansas State University. After practicing in North Dakota at a small animal practice, Dr. Lucas realized she missed the mountains and working in mixed-animal practice, so she came to Gillette in 1992.
At home, Susan has several pets of her own: three Sussex spaniels, a Scottish Fold cat, and a desert lynx cat. She’s been training and competing in obedience with her dogs for many years now. Dr. Lucas also enjoys hiking in the mountains with her dogs and has even been on several overseas trips for long-distance hiking.
Dr. Jen Hefftner
Dr. Hefftner's Bio
Dr. Hefftner grew up in Albuquerque, New Mexico, where she started her animal-care journey by working as a Veterinary Assistant at the age of 15. She then attended Colorado State University to earn both her Bachelor’s degree in animal science and her Doctoral degree from the school’s College of Veterinary Medicine, finding time between her studies to help raise puppies for the Guide Dogs for the Blind program.
Dr. Hefftner joined the Animal Medical Center of Wyoming team in June of 2016, and couldn’t be happier to practice high-quality veterinary medicine in a warm, welcoming family atmosphere. Medically, her favorite parts of her job are internal medicine cases and critical care work; she never tires of the fast-paced problem solving needed to arrive at a solution. Most of all, though, Dr. Hefftner enjoys getting to know the pet owners of the area on a daily basis.
Away from the office, Dr. Hefftner enjoys hiking and fishing in the great outdoors and is currently learning to snowmobile. She’s also an avid dancer, and even taught tap dance during veterinary school. Dr. Hefftner and her husband, who owns and operates a welding and excavating company, share their lives with several pets: Maple, an energetic bloodhound puppy who is constantly getting into trouble; two rescued cats named Shakespeare and Cinder who rule the house; and four playful goats who go by Kya, Ruby, Soda, and Mari.
Dr. Kalisch's Bio
Dr. Kalisch has always had an interest in biological sciences and surgery, so the veterinary field was the perfect fit! His favorite part of this field is surgery and seeing pets’ health improve from his care. He also loves working with small companion animals like cats and teacup breeds of dogs. All of his coworkers would describe him as a jokester!
Dr. Kalisch’s wife, Cindy, works at the local Senior Living/Assisted Care Facility. They have a son, Jake, who is a high school student and a history nut. They have a Catahoula Leopard dog named Mia who Dr. Kalisch rescued from an abusive owner. Outside of work, Dr. Kalisch enjoys all outdoor activities, particularly hunting.