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Our Doctors


Kathi Heiber, DVM

Originally from Cleveland, Dr. Kathi Heiber earned her degree in veterinary medicine from the Ohio State University College of Veterinary Medicine in 1979. Her first few years in practice in Brewster, NY were spent treating companion pets as well as farm animals and horses.

In 1984, Drs. Heiber and Cindy Kosacz founded South Putnam Animal Hospital in its present location in Mahopac, NY. The hospital was built to provide a high standard of veterinary care that they would want for their friends and family to receive for their beloved pets.

Dr. Heiber is actively involved in the community, and presently serves on the Board of Directors for Cornell Cooperative Extension of Putnam County and the Friends of Mahopac Library. She is also a leader with 4-H youth development programs that work with local youth interested in veterinary medicine. In addition, Dr. Heiber volunteers for AFS International Exchange Student Program welcoming students from foreign countries and supporting families who host students in their homes.

When Dr. Heiber is not practicing high-quality animal medicine or doing community service, you may find her riding her thoroughbred, Big Grin, or Arab Shagya mare, Lily. She also has a Jack Russell mix and two adopted cats. Dr. Heiber enjoys spending time with her husband, cooking through the seasons with fresh local produce, and exploring new cuisines.


Julie Fixman, DVM, DABVP

Dr. Julie Fixman earned her Doctor of Veterinary Medicine degree from Cornell University in 1998. Dr. Fixman is a compassionate and committed veterinarian, co-owner, and the Medical Director at South Putnam Animal Hospital.

Dr. Fixman became Board Certified by the American Board of Veterinary Practitioners in Canine and Feline Practice in 2007 after completing additional studies and examinations to achieve board certification. Her areas of professional interest include complex internal medicine conditions, soft-tissue surgery, and ultrasound. Dr. Fixman belongs to a number of professional organizations and is a former president of the Hudson Valley Veterinary Medical Society.

At home, Dr. Fixman's pets include Callie, a Golden Retriever, Spike, an Abyssinian cat, and an ever-changing number of chickens. She has a busy family life outside of the office with her husband, son, and daughter, and when she isn't inside an ice arena being a "hockey mom," she enjoys hiking, cooking, reading, skiing, and gardening.


Judith Mason, DVM

Dr. Judith Mason earned her degree in veterinary medicine from the University of Illinois in 1983. A Chicago native, she relocated to New York shortly after graduating. Dr. Mason started practicing high-quality animal medicine at South Putnam Animal Hospital in 1988, and is proud to be part of the practice's first-rate hospital family.

Dr. Mason is the mother of a son and a daughter who have been visiting South Putnam Animal Hospital since they were young. Now, both children are pursuing careers in human healthcare! Dr. Mason has a wonderful pet family, too. April is a wonderful Border Collie mix who was adopted as a puppy from the North Shore Animal League. She is an extremely active and fit senior who can still turn on a dime. Among April's many skills, she will shake water or snow off on command. Dr. Mason also shares her home with two handsome male cats, Lord Greystoke and Gingy. Both felines were originally strays, but are now happy indoor cats with a custom built pen attached to their home so they can visit the outdoors without getting into mischief.

In her free time, Dr. Mason volunteers at her synagogue, is an ESL teacher, and visits patients at the local hospital. She enjoys hiking with April, exercising, gardening and floral arrangements, and reading.


Maria Kremerman, DVM

Dr. Maria Kremerman joined the clinical team at South Putnam Animal Hospital in January 2018. She is a graduate of Ross University School of Veterinary Medicine where she earned her degree with honors in veterinary medicine on the beautiful island of St. Kitts, and completed her clinical training at Tufts Cummings School of Veterinary Medicine.

Dr. Kremerman grew up in New York with various pets from a young age, ranging from pocket pets to reptiles to dogs, and this is where her passion for healing and caring for animals began. She started volunteering at the NYCACC at the age of 15 and worked as a veterinary assistant for 5 years before going to veterinary school.

Dr. Kremerman is very passionate about veterinary medicine and loves helping both animals and the people that love them. Her professional interests include internal medicine, ophthalmology, and surgery.

At home, Dr. Kremerman's pets include Bart, Louie, and Skelly, all of which are rescues and two of which are foster failures. In her free time, Dr. Kremerman enjoys hiking with her dogs, sailing during the summer, scuba diving, cooking, and reading.


Carrie Begin, DVM

Dr. Carrie Begin joined the clinical team at South Putnam Animal Hospital as an Associate Veterinarian in September 2018. Born and raised in Michigan, Dr. Begin holds a Bachelor of Science degree in Biology from the University of Michigan, and she went on to earn her Doctor of Veterinary Medicine degree from Michigan State University College of Veterinary Medicine in 1998. She has areas of professional interest in internal medicine, dermatology, client education, preventative medicine, and pocket pets.

Inspired by her father's career as a veterinarian, Dr. Begin started on her own path in the veterinary field at the young age of sixteen years old. Today, her friendly demeanor and years of experience allow her to serve her clients and their pets with the highest level of care and compassion.

Dr. Begin had many family pets growing up, but her Shih Tzu, Mandy, was her first true forever friend. Currently, Dr. Begin has a Golden Retriever, Alta, and a senior cat, Ellie. In her free time, Dr. Begin enjoys spending time with her family, traveling, gardening, reading thrillers, and boating.


Our Practice Manager

Peggy Keating joined our staff in 1990. She oversees a variety of functions necessary for hospital operation, makes sure the hospital runs smoothly, allowing veterinarians and staff to focus on the health of the animals. She has a Pitbull named Shelby, and two Domestic Shorthair cats named Walter and Mildred.


Our Reception Staff

Our friendly and courteous receptionists are SPAH's customer care coordinators. Our receptionists are here to make your visit to our hospital as pleasant as possible. They are available to answer questions related to scheduling, billing, and basic animal care. Our customer care coordinators have both a love of animals and many years of experience at our hospital

Jennifer Shea joined our staff in 1995. She currently has a Labrador Retriever mix named Maybelle and 2 domestic shorthair cats Pearl and Otis.

Jen Bernstein joined our staff in 1997. She currently has an Oriental Shorthair named Pinkus.

Ann Clark joined us in 2014. She has two cats, a Domestic Shorthair named Shadow and Simba, and a Golden Retriever named Buddy.

Lacey Colao joined our staff in 2012 and her responsibilities include both Veterinary Assistant and Reception duties. She has a Pitbull named Xena.


Our Licensed Veterinary Technician Staff

In the veterinary world, a Licensed Veterinary Technician is an individual who has graduated from an American Veterinary Medical Association accredited college and received a license by the state to practice as a veterinary technician. Their training in treating animals combines the skills similar to those of a physician's assistant, nurse, and medical lab technician in the human health care field. You will meet our LVT's as part of your pet's appointments. They are responsible to prepare the patient for the doctor's examination. They are also responsible for patient lab work, performing radiographs, performing dental procedures, administering anesthesia and monitoring of surgical patients, and completing doctor's orders for medical procedures as well as expert nursing care.

Irene Baier, LVT joined our staff in 1997. She has a Cockapoo named Penny.

Lisa Forsythe-Kane, LVT joined our staff in 1996. She has a four terriers named Sprocket, Britt, Roo, & Biggie, and 11 felines of various breed, Boomer, Lilli, Melon, Nadia, Paire, Race, Raisin, ,Munson, Kraft, Felix and Sid aka Hairy Thursday.

Astri Teal, LVT originally joined our staff in 1996 as a Veterinary Assistant. After graduating from Mercy College, she received her Veterinary Technician License in 2001 and is currently one of the Licensed Veterinary Technicians at South Putnam Animal Hospital. She has two mixed-breed dogs, Mesa and Summit.

Michelle Pennisi, LVT joined our staff in 2017. She has a Havanese named Kitty.

Megan Sausedo, LVT originally joined our staff in 2003 as a Veterinary Assistant and is now one of Licensed Veterinary Technicians. Megan is also our inventory manager and is responsible for managing the practice's medical inventory which is crucial to the smooth flow of client service and patient care. She has a Chihuahua named Mouse.


Our Veterinary Assistant Staff

Veterinary Assistants are responsible to assist doctors and technicians with performing medical procedures and to provide companionship and expert nursing care to your pet.

Lacey Colao joined our staff in 2012 and her responsibilities include both Veterinary Assistant and Reception duties. She has a Pitbull named Xena.

Gina Guerreiri joined our staff in 2017. She has a Domestic Longhair Cat named Rizzo.

Annie Sherlock joined our staff in 2017. She has a Pitbull named Lily.

Ned Maguire joined our staff in 2018.

Andrea Jenkins joined our staff in 2018.