Our Small Animal Veterinarians
Dr. Jeffrey Korosec
Dr. Korosec graduated from the University of Wisconsin-Madison School of Veterinary Medicine in 1991. He joined Elkhorn Veterinary Clinic in 1992, becoming a partner in 1999. He entered the veterinary profession knowing that he loved animals and wanted to be capable of helping them. As a veterinarian, he quickly learned how gratifying it is to work with caring, capable staff to help not only pets but their owners as well.
During his time away from the clinic, Dr. Korosec volunteers at the Lakeland Animal Shelter and is on the advisory board for Gateway Technical College Veterinary Sciences Program. In addition to his wife and four children, his family also includes three dogs and four cats. Outside of work, Dr. Korosec enjoys spending time with his family, hiking, bicycling, camping, and seeing the national parks.
Dr. Nikki Preston
Dr. Preston completed her Bachelor of Science degree in biology at Illinois Wesleyan University before graduating from the University of Illinois College of Veterinary Medicine in May 2015. She always loved science and knew that she wanted to have a career in medicine. After contemplating human vs. veterinary medicine, Dr. Preston decided that she couldn’t ignore her love for animals and ultimately chose to become a veterinarian. She finds it rewarding to help owners make the best choices for their pets.
Dr. Preston has a four-legged family member of her own, a Lab mix named Chance. She enjoys traveling abroad, running, biking, and hiking.
Dr. Ellen Waller
Dr. Waller has always been interested in animals and had pets from an early age. She received her Doctor of Veterinary Medicine degree from the University of Illinois in 1980. She worked in a mixed animal practice and then joined the Peace Corps, where she worked with a cattle cooperative in Africa. Dr. Waller has been in small animal practice in this area since 1993 and joined Elkhorn Veterinary Clinic in December 2007. She has also pursued continuing education in ultrasonography and echocardiography.
For Dr. Waller, the most rewarding aspect of veterinary medicine is having a career that surrounds her with animals and the people who care about them, and that challenges her intellectually. There is always something new to learn.
Dr. Waller and her husband Gianni have a Dalmatian/Coonhound mix named Gemma; three cats named Nora, Trinity, and Tom; and four chickens named Goldie, Layla, Ruby, and Robin. Her hobbies include baking, reading, hiking, and other outdoor activities.
Dr. Liana Wiegel
Dr. Wiegel wanted to go into veterinary medicine since middle school when she got her first horse (that she still has to this day). She received both her animal science and veterinary degrees from the University of Wisconsin-Madison. After graduating from vet school in 2012, Dr. Wiegel completed a hospital and ambulatory internship at Pilchuck Veterinary Hospital just north of Seattle. She continued to work there as an ambulatory veterinarian until joining Elkhorn Veterinary Clinic in 2017. Her professional interests include equine dentistry, lameness, senior care, and ophthalmology. Dr. Wiegel also particularly enjoys treating alpacas, llamas, and other small ruminants.
She and her husband have three dogs, two goats, two horses, one llama, and a turtle. When not working, she enjoys spending time with her three dogs and pony, running, and cross-country skiing.
Our Equine and Large Animal Veterinarians
Dr. Robert Entwistle
Dr. Entwistle, one of the partners in the practice, graduated from the University of Illinois in 1981 and joined the Elkhorn Veterinary Clinic shortly after. He grew up on a livestock farm in central Illinois and as a child was very involved in helping to manage the livestock. He also enjoyed the treatment and reproduction aspects of the job, which lead to his goal of becoming a veterinarian.
Dr. Entwistle and his wife Betsy have four daughters and a son. His family also includes two dogs; a Pug named Sophie and a German Shepherd named Veda. His hobbies outside of work include golf, gardening and yard work, and relaxing with the family.
Dr. Philip Burns
Dr. Burns graduated from Colorado State University in 1986, and he completed an internship at Naperville Equine Hospital in 1987. That same year, he joined Elkhorn Veterinary Clinic and is now one of the clinic’s three partners. Helping his grandmother deliver lambs when he was five years old instilled in him a desire to become a veterinarian. Dr. Burns became more involved with horses through his experiences in riding and many jobs through college where he worked around horses all the time, mucking out stalls, running a boarding stable, and spending his summers volunteering for an equine practitioner.
Dr. Burns’ special interests include equine reproduction, lameness, and dentistry, which he also practices abroad seasonally in an equine specialty practice in New Zealand. He and his wife and their two daughters reside in Eagle, WI on a small hobby farm with three horses and a cat. Outside of work, Dr. Burns enjoys running, gardening, hiking, fishing, and just being in nature.
Dr. Tracy Busalacchi
Dr. Busalacchi (Dr. Tracy to her clients) decided at four years old that she was going to be a veterinarian. She graduated from the University of Minnesota School of Veterinary Medicine in 1997 and joined the staff at Elkhorn Veterinary Clinic in 2000. Dr. Busalacchi’s many memberships include organizations such as AVMA, WVMA, AAEP, MVMA, and AERC. She is deeply involved with horses, especially endurance riding, and has membership in the AQHA, APHA, and AHA. Dr. Tracy’s specific areas of interest include veterinary spinal manipulation therapy (she obtained certification from the Healing Oasis & Wellness Center), reproduction, emergency medicine, internal medicine, and sports medicine. She also completed the Advanced Functional Neurology Program at the Healing Oasis & Wellness Center.
Dr. Tracy and her husband have a twin son and daughter, five horses, six cats (including barn cats), two dogs, four fish, and seven chickens.
Dr. Tess Tucker
Dr. Tucker grew up in the southwest Chicago suburbs. She first became interested in horses and large animals as a youngster growing up and participating in 4-H. She received her animal science and veterinary degrees from the University of Illinois. After graduating veterinary school in 2019, she completed an internship in equine surgery and medicine at Kendall Road Equine Hospital in Elgin, Illinois. Her current areas of interest are sports medicine and preventive care.
Dr. Tucker and her boyfriend enjoy spending time with their two corgis and herd of guinea pigs as well as her quarter horse, Godiva.
Dr. Ashley Slater
Dr. Ashley Slater grew up in rural Oklahoma on a farm with horses and beef cattle. She started showing horses in the English discipline when she was young as well as showing cattle in FFA.
Dr. Slater studied Animal Science at the University of Arkansas. She received her D.V.M. from Oklahoma State University Center for Veterinary Health Sciences in 2018. She then went on to complete a one year rotating equine internship in surgery, medicine, and sports medicine at Brazos Valley Equine Hospitals in Salado, Texas.
Dr. Slater joined the Elkhorn Veterinary Clinic team in October of 2019. Her primary interests include equine lameness, medicine, and wellness. In Dr. Slater’s free time, she enjoys spending time with her two cats, Boots and Yogi, riding her horses and hiking.
Dr. Colleen Stewart
It is with both joy and sadness that after 25 years with the Elkhorn Veterinary Clinic, we announce Dr. Colleen Stewart’s retirement. Naturally, we are happy for Dr. Stewart that she will now have the time to spend with her family whom she loves so dearly. But that happiness for her is tempered with our loss of not only an exceptional veterinarian, but a wonderful friend. We wish her the best of luck for a long and happy retirement.
Dr. Stewart would have liked to have been able to personally say goodbye to all of her clients. Unfortunately, with the coronavirus pandemic that was not possible. She did, however, want each of you to know the following:
“The time has come for me to formally announce my retirement. It is with much gratitude that I say goodbye to the clients and patients that I have known over the last 25 years at the Elkhorn Veterinary Clinic. I feel very blessed to have had the opportunity to care for your four-legged family members as well as share in your lives. Over the years you have helped me to grow as a veterinarian and as an individual, and I thank you for sharing your lives with me.” ~ Colleen Stewart, DVM
Although Dr. Stewart has retired, please rest assured that our current team of veterinarians and staff are here to care for your pets. Thank you for your continued support and patronage. Please feel free to contact our clinic if you have any questions or concerns. We are looking forward to seeing you and your pets soon!