Monday: 9:00 am – 11:30 pm
Tuesday: 9:00 am – 11:30 pm
Wednesday: 9:00 am – 11:30 pm
Thursday: 9:00 am – 11:30 pm
Friday: 9:00 am – 11:30 pm
Saturday: 9:00 am – 11:30 pm
Sunday: 9:00 am – 11:30 pm
Monday: 9:00 am – 11:30 pm
Tuesday: 9:00 am – 11:30 pm
Wednesday: 9:00 am – 11:30 pm
Thursday: 9:00 am – 11:30 pm
Friday: 9:00 am – 11:30 pm
Saturday: 9:00 am – 11:30 pm
Sunday: 9:00 am – 11:30 pm
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CEO
William O’Leary was raised in Chatsworth, California, in a family of horse trainers. Growing up surrounded by horses, hounds, and various farm animals, he developed a deep love for animals. At the age of 18, he secured his first job at an animal hospital, where he started by cleaning cages. Over time, William acquired technician skills and gained experience working at both a day practice and a local animal emergency clinic.
Later, William transitioned into veterinary pharmaceutical sales for IGI and laboratory sales for AVA. In 1998, he founded Mission Veterinary Clinic. He diligently grew the business, balancing his sales job during the day and working at the animal emergency clinic at night.
In 2022, William moved Mission Veterinary Clinic to its current location, just a few doors down from the previous site. This expansion provided the clinic with a much-needed facelift and brought in new doctors and staff.
William’s youngest son is currently in veterinary school and is expected to join the family business soon. In his spare time, William enjoys mountain biking, snow skiing, and wildlife photography.
Veterinarian
Dr. Sefildzhian’s journey to veterinary medicine began at a very young age. In high school, she enrolled in a veterinary science magnet program, which sparked her passion for animal care. She continued her education at Pierce College, taking animal science classes. Dr. Sefildzhian started working as an assistant at Mission Veterinary Clinic in 2009 She later moved to Chico, CA, where she earned a Bachelor’s degree in Microbiology from California State University, Chico. She then attended Ross University School of Veterinary Medicine in Saint Kitts and completed her clinical training at Michigan State University.
A few years after graduation, Dr. Sefildzhian returned to Mission Veterinary Clinic. She considers the best part of her day to be when puppies or kittens arrive, affectionately referring to these moments as “taxes” because she must stop whatever she is doing to give them hugs and kisses. Dr. Sefildzhian is dedicated to continuing education, consistently taking classes to enhance her skills and knowledge. Her professional interests include surgery, preventative care, and client education.
Outside of work, Dr. Sefildzhian enjoys spending time with her family and friends.
Veterinarian
Dr. Thak’s love for animals started early in life, growing up in South Korea. Following graduation from Konkuk University in Seoul, South Korea in 2011, she completed an internship and residency course at the same school gaining valuable experience in animal care and treatment. She then spent more years working at a general practice in Seoul before moving to the United States. In 2020, she began practicing veterinary medicine in New York State, where she worked in Corning for a year and then relocated to this area. She possesses a profound commitment to the fields of surgical medicine and preventative healthcare. Outside of work, she enjoys spending time with her husband and two sons, who are a constant source of joy and inspiration.
Veterinarian
Dr. Li had a keen interest in pets as a boy. His childhood was filled with numerous dogs, cats, rabbits and fish. He was born and raised in China. He was a veterinary graduate of China Agricultural University and trained at the University of Guelph at Canada. He started chasing his American dream in 2012 and successfully completed ECFVG and NAVLE in 2017. His career included one year in emergency medicine in Michigan and two years in general practices in Texas. California became his destination in 2020.
In the clinic, he is interested in small animal surgery and emergency medicine, and strives to excel in these areas. In his spare time, he likes bicycling, fishing and mountain climbing.
Manager
Danny has been a cornerstone family member of Mission Veterinary Clinic since 2003, and we are truly blessed to have him with us. As a dedicated manager, he excels in every facet of the hospital, working tirelessly to assist both our clients and their pets. Danny’s passion for animals has been evident since his childhood, where he grew up with three German Shepherds. Even today, he can’t resist leaving his office to greet every German Shepherd puppy that visits our hospital.
With a natural ability and deep compassion for animals, Danny’s career path began in college with a focus on animal science. Later, he obtained a degree in computer science, which has greatly benefited our hospital.
Outside of work, Danny enjoys spending quality time with his wife and four kids. He has a diverse range of interests, including photography, cooking, and computer engineering. His upbeat attitude and strong work ethic make him an invaluable asset to our team. It’s a rare hour in our hospital when you don’t hear a staff member asking, “Where is Danny?”
Shift Supervisor
Gabriel has been a valued member of the Mission family since 2008. His lifelong passion for animals was nurtured on his family’s farm in Colombia. While attending animal science classes at Pierce College, Gabriel joined the team at Mission Veterinary Clinic. He has always had a deep love for animals and currently enjoys the company of a spunky Maltese. In his spare time, Gabriel loves hiking and creating cherished memories with friends and family.
Shift Supervisor
Andy joined Mission Veterinary Clinic in 2015, starting his journey with a deep commitment to animal care. His passion for veterinary medicine began in high school, where he dedicated months to volunteering, assisting, and cleaning before being offered a position as a veterinary assistant.
Andy pursued his academic interests in Animal Science at California State University, Chico, and further honed his expertise by completing a year of veterinary studies at UNR Facultad de Ciencias Veterinarias in Argentina. He is currently wrapping up his undergraduate courses, working towards a Bachelor of Science degree to pave the way for his application to veterinary school in the USA.
As a supervisor at Mission Veterinary Clinic, Andy’s dedication and hard work shine through in every aspect of his role. His background in competitive water polo and swimming, where he achieved success at the highest levels, has instilled a sense of discipline and focus that he applies to his veterinary career.
In his downtime, Andy balances his rigorous schedule with his love for playing water polo and video games, always striving to maintain a well-rounded lifestyle. His commitment to both his profession and personal interests makes him an invaluable member of the Mission Veterinary Clinic team.
Shift Supervisor
Jeanette graduated from UC Davis with a Bachelor of Science degree in Animal Science, specializing in companion and captive animals, and minoring in Nutrition and Food. Before joining Mission Veterinary Clinic in 2019, she gained valuable experience working in laboratories. Currently, she serves as a lead in the back staff, managing workflow and ensuring that patients receive the highest quality care. Jeanette is a dedicated advocate for her patients, known for her outspoken nature and constant pursuit of improvement. She is a proud pet parent to Chueco, Berlíoz, Ms. Mailey, and Rusty. Jeanette is a highly valued member of our team.
Veterinary Assistant
Patrick O’Leary, the youngest son of William O’Leary, was born during the construction of the original Mission Veterinary Clinic. Raised in the veterinary hospital, Patrick grew up assisting his family with various tasks, starting with emptying trash and cleaning cages as a young child.
To stay in shape, Patrick enjoys running with his German Shepherd, Heidi. In his spare time, he indulges in snowboarding and playing video games.
Patrick completed his undergraduate studies at California Lutheran University in Moorpark. Currently, he is a third-year veterinary student at WesternU College of Veterinary Medicine, set to graduate in 2026. Upon graduation, Patrick plans to work full-time at Mission Veterinary Clinic.
Veterinary Assistant
Shadyra began her career in veterinary medicine in 2006 at a different hospital before joining Mission Veterinary Clinic in 2016. She is highly detail-oriented and the go-to person when something can’t be found. Shadyra is dedicated to continuous learning, regularly reading and watching videos to enhance her knowledge of veterinary medicine, striving to be the best assistant possible. She cares deeply for all patients and consistently goes above and beyond for them. Shadyra has three dogs—Maggie, Georgie, and Lalo—who inspire her to treat clients’ pets like family. When Shadyra is caring for your pet at Mission Veterinary Clinic, you can be assured your pet is in good hands. In her spare time, she enjoys playing video games.
