Our Team

Dr. Mark Fox

Dr. Mark Fox graduated from Michigan State University in 1984. Originally from Fremont Michigan he joined the practice right after college. He and his wife Jane have three children; Katie Chambers and her family in Holly Michigan, Anna Creech and her family in West Alexandria OH, and Paul and his family who reside in Millersburg, MI. Mark’s interests in the practice include dairy production, medicine, and nutrition. He enjoys anything outdoors including fishing, hunting, camping, and of course, motorcycling.

Dr. Leon Roggenbuck

Originally from Harbor Beach, Dr. Leon Roggenbuck joined the practice in 1992 after graduating from Michigan State University. He and his wife Amy are raising two children, Ethan and Emma. They reside in the area. Leon works primarily with dairy management. He enjoys being outdoors hunting. Leon is a member of the Knights of Columbus and the Sanilac County Right to Life Chapter.

Dr. Jarrett Gordon

Dr. Jarrett grew up in the area with several family members as clients of TVS, formerly Deckerville Veterinary Clinic. He always knew he wanted to stay in the area and worked on dairies in high school and through college. Reading James Herriot’s books gave him the desire to be a country vet. Pulling his first calf on a dairy during his senior year of high school is when veterinary medicine became his definite career choice. Almost everything about the large animal rural veterinary job has encouraged his choice of profession, from the animals to the farmers who feed the world! He joined Thumb Veterinary in 1996 and became the Owner in 2000. He’s a member of the AVMA, MVMA, and AABP. These organizations support veterinarians in the political/governmental realms. He’s been married to his wife, Bethany, for nearly 20 years, and they have four children. Their faith in Jesus Christ is the foundation of their lives and he served for over 16 years as a deacon/elder of their church, even preaching occasionally as needed.

Dr. Ann Roberts

Dr. Ann Roberts, companion animal veterinarian, joined the practice in 2007. Originally from Waterford, Michigan, Ann graduated from Michigan State University in 1999. She and her husband Chuck practiced Veterinary Medicine in Twin Bridges Montana before coming to Deckerville. Dr. Ann enjoys internal medicine, and surgeries. Ann and Chuck reside in the Deckerville area with their two daughters, Alexa and Emma. In her spare time she enjoys the many animals on their farm, reading, outdoor activities and of course the kids.

Dr. Chuck Roberts

Dr. Chuck Roberts joined the practice in 2007. Originally from Deckerville, Chuck graduated from Michigan State University in 1999. He practiced Veterinary Medicine in Twin Bridges Montana before returning to Deckerville. Dr. Chuck’s background includes working with bovine and on occasion companion animals. He and his wife, Dr. Ann Roberts reside in the Deckerville area with their two daughters, Alexa and Emma.

Dr. Monya Vaughn

Dr.Vaughn, a companion animal veterinarian, grew up in Port Sanilac, MI. She was an animal lover from a young age growing up riding horses. She rode a variety of disciplines but focused on western all around showing in APHA. She attended the University of Findlay for her undergraduate and studied business and equine science. During her undergraduate studies she worked training Quarter Horses and Paints in all around western disciplines. Prior to veterinary school, she completed an internship at the University of Findley’s Western Equestrian center assisting in farm management. After veterinary school she completed a rotating veterinary internship at Conley and Koontz Equine Hospital near Fort Wayne, IN. Dr. Vaughn now resides in Port Sanilac, MI with her husband and daughter. Her veterinary interests include lameness, reproduction, wound management and dentistry. In her free time, she enjoys outdoor activities, such as riding, sailing, hiking and camping.

Dr. Kevin Vaughn

Dr. Vaughn joined the Thumb Veterinary Services’ team in the fall of 2015. Kevin graduated from Iowa State University College of Veterinary Medicine, where he met his lovely wife Monya (also a veterinarian at the practice). Having grown up in upstate New York’s dairy heartland, Kevin is very comfortable calling the Thumb home. With two prior years of experience in companion animal medicine, Kevin is eager to focus on companion animal internal medicine, dentistry, and preventative care; in addition to equine ambulatory work. Kevin enjoys competing in triathlons, brewing, and winter sports. Kevin and his wife have two horses, two cats, and two dogs.

Dr. Lauren Lauwers

Lauren graduated from Michigan State University College of Veterinary Medicine in 2018. She spent her first year practicing food animal medicine in Central Valley California working mostly with dairies and beef ranches. She is excited to return home to the Thumb of Michigan where her family farms wheat, soy, corn, hay and raises lamb and steers. She enjoys the outdoors, musicals and spending time with her family.

Dr. Gianna Covelli

Dr. Gianna Covelli is originally from Charleston, West Virginia. She is a recent graduate from Mississippi State University College of Veterinary Medicine. She now lives in Richmond, Michigan with her boyfriend who will be doing a surgical residency at Mclaren Macomb in Mount Clemens. Dr. Gianna has two shetland sheepdogs, Gracie and Taylor, who rule the roost. She has an interest in both companion animal and equine medicine, and her specific areas of interest include preventive care, surgery and internal medicine. In her spare time Dr. Gianna enjoys spending time with family and friends, kayaking, traveling, and going to the beach.

Dr. Bryan Everly

Bryan is a Partner at Thumb Veterinary Services. He joined the partnership in January 2023, bringing with him a wealth of knowledge and expertise in the field. Originally from Ontario, Ohio, Bryan completed his undergraduate studies at the University of Findlay and went on to earn his veterinary degree from The Ohio State University in 2019. He began his career at TVS in 2019 and returned to the practice after a short period of time back in Ohio.

Bryan has a passion for working with animals, which began through his involvement in 4H with livestock, specifically show cattle. This led him to pursue a career in veterinary medicine, and he enjoys making connections with animal owners through his work. As a veterinarian, Bryan’s professional interests lie in dairy medicine, specifically in reproduction and employee development/training, as well as bovine advanced reproductive techniques. He is a member of several veterinary associations, including AABP, AETA, MVMA, and AVMA.

Outside of work, Bryan resides in Palms with his wife, Victoria, and their two children. He enjoys hunting and fishing, and spending quality time with his family.

Dr. Marina Sweet

Marina graduated from Ohio State University College of Veterinary Medicine in 2022! She is a double Buckeye as she also went to OSU for undergraduate and studied Animal Sciences, she then joined the team as an associate Veterinarian July of 2022! By moving to Sandusky, she is returning to her Michigan roots because she was born and partially raised in a Detroit suburb. When Marina’s family moved to an agricultural community in Ohio back in 2008, she joined 4-H and found her passion for livestock. She started working on dairies in high school and never looked back!

Marina’s 4-H experience exposed her to a wide variety of livestock species and gave her the opportunity to lease a dairy heifer from a local farmer. Later, she started helping feed calves at that farm and found a passion for dairy cattle. From that point forward, she worked on numerous dairy and beef cattle operations but retained a soft spot for hobby farms and small ruminants because of her 4-H experience. Marina’s professional interests are dairy, small ruminants, and some companion animal work. She loves getting to work with small hobby farms and “pet” livestock clients because it helps future generations be exposed to agriculture!

Outside of work, Marina loves spending time with her fiancé, Garrett, cooking, reading, exercising, and traveling. Her future goals are to have her own hobby farm with chickens and sheep!

Dr. Calli Felster

Dr. Felster has built her life around a profound love for animals and a commitment to her community. Hailing from Ruby, Michigan, she embarked on her educational journey at Iowa State University College of Veterinary Medicine. Her passion for equine care flourished during her year at Saginaw Valley Equine Clinic, where she became well-versed in lameness, reproduction, wellness, and internal medicine for horses of all sizes. Her favorite aspect of the profession is the constant learning it offers, coupled with the joy of working with diverse clients and their pets. Dr. Felster actively engages with organizations like 4-H and university Pre-Vet Clubs, showcasing her commitment to community involvement.

In her professional pursuits, Dr. Felster focuses on equine and companion animal medicine, with particular interests in equine internal medicine, equine sports medicine, and feline internal medicine. She is a proud member of several professional associations including AAEP, AVMA, MVMA, and she is a committee member of the MVMA’s Michigan Equine Practitioners Committee. Beyond her veterinary endeavors, Dr. Felster is an avid college football fan and former CMU Chippewa Marching Band alumna. She relishes outdoor activities with her husband, whether it’s camping, kayaking, or exploring trails. Her downtime is spent with her canine companions, including Greyhound Gina and Shepherd/Lab Mix, Five-O. During the summer, she collaborates with Iowa State and the Rosebud Sioux tribe of South Dakota, providing no-cost equine care to the tribe’s horses while teaching students of the university. 

Dr. Jared Sanderson

A 2023 graduate of Michigan State University’s College of Veterinary Medicine, Jared is an associate Veterinarian on our team. He brings experience and passion in bovine reproduction, milk quality, feed management, and employee development/training. He is committed to delivering the best medical knowledge to our clients to help maximize their herd’s potential while also ensuring their animal’s health.

Jared attended Michigan State University for Animal Science. Go Green! His undergraduate learning focused mainly on dairy cattle and ruminant nutrition. He also held leadership roles in the MSU Dairy Club and MSU Block and Bridle Club. Additionally while at Michigan State he was heavily involved in the Dairy Challenge team, competing at the local, regional, and national levels. In that program he gained experience dealing with the unique dynamic between ensuring herd health and farm financials.

Jared was first introduced to dairy cattle through his grandfather and uncle who continue to own and operate a dairy in Croswell, MI. Growing up, he was an active member in 4-H, showing at the Sanilac County Fair and serving on the Dairy Committee. This experience allowed him to make lifelong connections and fueled his passion for animal agriculture. Throughout his time at Michigan State and vet school, Jared held positions in ruminant nutrition and veterinary pathology laboratories, and several farms within Michigan and South Dakota.

When not at work, Jared enjoys spending time with his wife, Libby, and their two dogs. As a family they enjoy golfing, football, paddle-boarding, and following Spartan athletics.

Debi Vanerp

Practice Manager

Debi joined Thumb Veterinary Services in August 2020. She received her B.S. in Animal Science and her M.S. in Crop and Soil Sciences, both from Michigan State University. Debi resides in the Cass City area with her husband, Chuck, and their six cats. In her free time Debi enjoys reading, listening to music, camping/hiking, and spending time with her family and friends. If you have any questions or concerns, feel free to reach out to Debi by email at debiv@thumbvets.com or by dialing extension 109 on either of our phone lines.

Sarah Thompson

Sarah Thompson is the Chief Financial Officer at Thumb Veterinary Services, where she has been an integral part of the team since August 2017. Starting her journey as a receptionist, Sarah’s dedication and expertise led her to her current position. A proud graduate of Baker College with a Bachelors in Business Administration in 2007, Sarah hails from Sandusky and now calls the Marlette area home with her husband Chris and daughter Sophia. Beyond her financial acumen, Sarah finds joy in travel, music, arts & crafts, baking, gardening, and cherishing moments with family and friends. For any inquiries, you can reach Sarah at extension 129 on either phone line.

Kayla Perry

Kayla Perry joined our team as a receptionist in October 2019. Kayla and her husband live in Marlette and have 3 children. They also have four dogs, Jazzy, Chloe, Winston, and Harold. Kayla enjoys camping and spending time with her family.

Sheena Dickinson, LVT

Sheena has been with Thumb Veterinary Services since 2003. She is a Licensed Veterinary Technician. She is a graduate from Macomb Community College. She resides in the Peck area with her husband Casey and their two daughters, Raelynn and Emerson. She enjoys shopping, reading, and gardening.

Tricia Krueger

Tricia Krueger has been with the clinic since 2001. Her duties at the clinic consist of inventory management, and assisting the technicians and doctors with patient care. Tricia and her husband Dave reside in the Snover area. They have a daughter Erin and three beautiful granddaughters Quinn, Mayzie and Mylah. Tricia is our cat lady here at the clinic. In her spare time she enjoys going antiquing, flea markets and spending time with her family at their cabin

Ali Schuette

Ali joined our clinic in June of 2020 as a veterinary assistant. She assists primarily with our small animal patients. Ali is originally from the area and resides near Cass City on her family’s farm. Her hobbies include traveling, camping, shopping, and spending time with her family and her dachshund, Otis.

Chelsea Messing

Chelsea joined the practice in 2017, as an Equine Veterinary Assistant. She grew up in the Carsonville area and still resides there with her husband Adam and their two boys, Blake and Brady. Chelsea grew up on a small farm and has been around horses since she was born. She grew up riding and showing Quarter Horses in the all-around events, focusing on Hunt Seat and Western. She currently has a dog and a cat at home, with three horses still on the family farm. Chelsea enjoys riding and showing her horse Wilson, camping as a family, and farming with her husband.

Kerra Gregg

Kerra began working in the veterinary industry because horses are her passion and she loves to help animals. She’s currently an Equine Veterinary Assistant here at Thumb Veterinary Services. Kerra and her husband Dylan reside in the Yale area with their dog Harley and horse Nash. Her personal interests are horses, traveling, and photography.

Danielle Clarke

Danielle is a Veterinary Assistant. She grew up in Sanilac County and came back to the area in 2019.  She grew up around various animals, knowing she always wanted to do something with animals. After college she became interested in the veterinarian industry. Her favorite thing about working with animals is the excitement and variety between each animal.  During her spare time she enjoys cooking, reading a good book and spending time outside with her two dogs.

Kim Gadzinski

Kim joined the team as a Small Animal Receptionist in April of 2011!

She resides outside of Peck with her husband Michael. They have 4 adult children, 2 grandkids and 3 miniature horses! Outside of work Kim enjoys traveling, going to concerts & gardening.

Kasey Watson

Kasey Grew up in Port Sanilac and attended Deckerville High School. She’s always loved being around critters of all sorts and interacting with them so this is the perfect job for her!

She stays in Marlette and her pride and joy is her cat Mary! In her free time Kasey loves gardening, reading, organizing, and spending time with the ones she loves.

Tori Smith, LVT

Tori is a licensed veterinary technician that started working here in the spring of 2021! She graduated from Baker College in the spring of 2021 with an Associates degree in veterinary technology. She is originally from the Carsonville area and decided to return to the area after graduation. She has always loved animals, and wanted to work in the industry to help the well being of them.

Outside of work, Tori  enjoys camping, fishing, hunting and spending time with family and friends. She has two dogs at home Lucky and Sparty who also enjoy camping with Tori!

Jessica Mott, LVT

Jessica is a dedicated Licensed Veterinary Technician at Thumb Veterinary Services, backed by an associate degree from Macomb Community College. Originally from Richmond, MI, she’s called the thumb area home for 28 years, drawn by her passion for farm life.

Jessica’s veterinary journey is rooted in her childhood on a dairy farm and her commitment to nurturing the human-animal bond. Clients frequently praise her for her calming presence with their pets. Outside the clinic, Jessica treasures time with her husband, Matt, their three kids, and an assortment of beloved animals. She’s also an active 4-H leader, gardener, and scrapbooking enthusiast.

Todd Dennis, LVT

Todd, a Licensed Veterinary Technician at Thumb Veterinary Services since January 2024, hails from the picturesque thumb region of Michigan, where he grew up and continues to work on a family farm. His journey in animal care began during his high school years when he actively participated in the FFA, serving as the local chapter’s secretary and representing the state as a delegate in 2012.

In 2016, Todd graduated from Baker College of Flint with an Associates in Veterinary Technology, marking the foundation for his subsequent roles in the veterinary field. Before joining Thumb Veterinary Services, Todd held diverse positions, including emergency technician, surgery technician, and specialty technician supervisor at a specialized and emergency hospital in the metro Detroit region.

Todd’s passion for working with animals has been a lifelong commitment. As a licensed technician, he is dedicated to ensuring a positive client and patient experience through compassionate, professional, and thorough patient care practices.

Outside of his veterinary duties, Todd remains deeply connected to his roots, working on the family farm. His personal time revolves around his daughter, Gracelyn, and his beloved pets—Elliott, a Boxer, and two cats named Aspen and Forrest. An avid outdoor enthusiast, Todd can often be found hiking, hunting, gardening, or kayaking when not immersed in his veterinary responsibilities at Thumb Veterinary Services.

Teryan Block, LVT

Teryan’s journey towards her current role was shaped by her educational background. Teryan pursued a veterinary technician degree at Baker College in Clinton Township, showcasing her commitment to excellence in her field. Hailing from a family beef farm in the thumb, Teryan’s roots are firmly grounded in the agricultural lifestyle of her upbringing.

Outside of her professional pursuits, Teryan finds joy in spending time with friends and family. She cherishes moments of relaxation and connection, often going on refreshing walks with her beloved dog. Teryan’s multifaceted life reflects a balance between her professional dedication and the fulfillment she finds in her personal interests and relationships.

Debi Vanerp

Practice Manager

Debi joined Thumb Veterinary Services in August 2020. She received her B.S. in Animal Science and her M.S. in Crop and Soil Sciences, both from Michigan State University. Debi resides in the Cass City area with her husband, Chuck, and their six cats. In her free time Debi enjoys reading, listening to music, camping/hiking, and spending time with her family and friends. If you have any questions or concerns, feel free to reach out to Debi by email at debiv@thumbvets.com or by dialing extension 109 on either of our phone lines.

Jodi Veldman

Jodi Veldman joined Thumb Veterinary Services as a receptionist in November of 2018. Jodi and her husband of 20 years Jason, reside in the Yale area where they own a small beef farm. They have 2 kids, Kylie and Gavin along with 3 dogs and 2 cats. Jodi is a 4H Leader and is involved with St. Clair County 4H and Youth Fair. She enjoys spending spare time camping, doing yard work and working out. If you are trying to get into direct contact with Jodi, she can be reached by dialing extension 102 on either phone line.

Rhonda Durecka

Rhonda joined Thumb Veterinary Services in September of 2019. She’s lived in the thumb area most of her life. Rhonda and her husband, Glen, have 3 kids, Mason, 14 years old, Delainey, 3 years old and Layla, 10 months and they reside in the Lexington area. She’s involved in the Sanilac County 4-H program where they show beef, dairy cattle, and hogs. They have a small beef herd, one pony, a goat, a dog and one cat. In her spare time, Rhonda likes reading, baking and gardening.

Olivia Shoemaker

Olivia joined the team as a large animal receptionist in December of 2022! She resides with her husband, Andrew, in Marlette area on a small 5 generation dairy farm. She raised Boer Goats in the past, and now owns 3 horses, and 2 dogs!

Outside of work, Olivia loves horseback riding, hunting, fishing, and crafts which she very much enjoys.

Samantha Schmidlin

Samantha has lived in the area her entire life and is currently our incredible receptionist!

Outside of work, Samantha & her wonderful husband JJ and have 3 children together, Logan, Levi and Maisyn. In their spare time they love being outdoors, going camping, playing at her dad’s farm and just hanging out with family. They also have 3 dogs Ollie, Finn and Zoey and 2 horses Arrow and Ebony!

Keysha Smith

Keysha grew up in the area on her family farm raising various animals, crop farming and helping with the family business, excavating and farm tiling! Growing up in the farming community Keysha always had a strong passion for the production animal industry and agriculture. “The livestock industry is just who we are as a family”.  Keysha’s husband is a livestock nutritionist, so going to work just feels like working with an extension of family.

Outside of work, Keysha, her husband Spencer, their son, and dog reside on their small beef farm raising calves for show and production as well as a flock of chickens, and their son feeds out a few market pigs throughout each year. In her spare time Keysha loves to bake, can fruits and veggies, go to the gym, attend cattle shows, volunteer with the local fair’s breeding beef program, but most of all she loves to spend time with her husband, son, and extended family!