About Our Hospital

Welcome to Sierra Veterinary Hospital, your local veterinarians in Stockton, CA.

Providing quality pet care since 1958, Sierra Veterinary Hospital is proud to offer Stockton’s most advanced veterinary care and grooming facilities for our patients. Our team of doctors, technicians, and support staff utilize the latest advances in veterinary medical technology to provide a lifetime of love and care for your pets.

Meet our caring and compassionate veterinary care team.

Meet the Veterinarians & Team of Sierra Veterinary Hospital in Stockton. We’re pleased to provide exceptional vet care for your pets.

Please call us at (209) 477-4841 to speak to one of our caring veterinary staff members.

Our Doctors

Dr. Cindy Yao

I live in Stockton with my husband Brian, our Dachshund, Goose, and our Calico cat, Tuna.

I graduated from University of the Pacific with a bachelors in Biological Science and completed my veterinary training at Ross University in St. Kitts, in the West Indes.

Since childhood, I have been interested in both animals and medicine. My family raised small birds including parakeets, cockatiels and quails, and there was always a dog or cat or two around the house. As time went on, I realized that I could combine both of my passions with a career in veterinary medicine.

When I’m’ not at the clinic, I like to read science fiction novels and bake cookies, pies, cakes and tarts.

Dr. Marlena Cleary

Hello! I’m Dr. Marlena Cleary. I am very excited to meet you and provide excellent care for your pet.

I was born about an hour away from Stockton in the foothills. I had a strong interest in science and biology since I was very young. I enjoyed learning about the diversity of animals and I started working for a small animal clinic in high school. Once I saw the combination of biology and caring for animals I was hooked and was committed to going to veterinary school after my undergraduate education. I graduated from UC Davis with my doctorate in veterinary medicine in 2013 and got married to my husband later that year. We have two cats. One of my cats is an overweight sloth and my other one is a trim worrywart but I love them both very much.

My husband and I like to get outdoors and explore California for fun. I have my advanced diving certification and my husband just got his beginner certification. We are also slowly going through the best hikes within Sacramento area. I am a novice sewer and when I have time I enjoy watching and practicing ballet and ballroom dance.

There are so many great parts of my job. I love getting the opportunity to improve the lives of pets by providing advice on preventative care from tooth brushing to weight loss. I also get the chance to help pets and their owners through illnesses. The best part of my job is when I can really impact a pet’s health in a positive manner.

I look forward to meeting you and your pets on your next visit to Sierra Vet.

Dr. Sydney Gillam

Hello, I’m Dr. Sydney Gillam and I am so excited to be a part of the Sierra Veterinary Family.

I live in Galt with my husband, Ryan and our cat, Oni. We are both born and bred California natives. I graduated from Chico State with a bachelor degree in Animal Science and completed my schooling at University College Dublin, Ireland.

Puzzles fascinate me and veterinary medicine allows me to combine my love of puzzles with a scientific mindset. I have always wanted to be a veterinarian and none of my family and friends are surprised I’ve made it happen. I am passionate about preventative medicine and believe the best way I can help my furry friends is by ensuring their best health today.

Now that I am done with my schooling, I spend any free time reading and ballroom dancing. I am an avid chef and an amateur baker.

Our Veterinary Technicians

Jenee Giottonini

Hi, my name is Jenee. I started working here at Sierra while attending school to become a Registered Veterinary Technician. I have since graduated and have an A.S. degree in Veterinary Technology. I have now been here at Sierra since 2007, and I have also gained experience working at an emergency clinic.

At a very young age I knew that I wanted to work with animals in some capacity, so I feel very lucky to have found a good position here at Sierra. Working with all of the animals and watching puppies grow into adult dogs is one of my favorite aspects of this career. I really enjoy caring for others pets while I am away from my own.

My boyfriend and I have two boys; a Doberman Pinscher named Yoshi Feroschi and a rescued Rat Terrier named Tucker. I also have had my Lhasa Apso mix, Dojaa, since she was six weeks old. If I had my way, we would have at least 4 more dogs! In the meantime, I like to try as often as possible to help the stray dogs that are brought in find a home. That is actually another thing I enjoy about Sierra Veterinary Hospital; we try as a hospital and as a staff to help shelter animals and abandoned animals find good homes. Hopefully, in the future I can be a bigger part of this process.

Jennifer Wang

Hello, my name is Jennifer and I have always had a soft spot for animals, which is why I am currently working towards a career in the animal field. When the opportunity came up to work at Sierra, I jumped at the chance because I can’t think of a better place to start off at. I have a boxer named ‘Ninja’, and she is my joy. She travels everywhere with us and has become the best road trip partner, one could ask for. I am extremely excited to be part of this staff because everyone that I have met at has been extremely helpful and welcoming, which is the same attitude that they apply to anyone that walks through the door-so walk on through.

Megan Jumanan

Hello, my name’s Megan and I live with my two dogs, Nemo and Tyson. I just finished school at Carrington College for Veterinary Technology. I first started at Sierra Vet doing my externship and was hired as soon as I finished. Since then, I am now in the training process; which consists of half front office work and half technician work. I became interested in Veterinary Medicine since I can remember. I’ve always had a soft spot for animals and being able to help them when they cannot speak for themselves is a very satisfying feeling. What I like most about my job is of course being able to help animals and their owners; but also building a relationship with them. I like being able to recognize when a client comes in, and know immediately which pets they have and just asking them how they are doing. When I am not here at the clinic I am usually at home playing my guitar and always learning about music.

Katie Estoll

Hi, my name is Katie Estoll and my husband is Buddy Estoll. We have six pets together: two cats, two rats, a dog, and a bearded dragon. All of our pets are named after Greek gods and mythical creatures.

I have been with Sierra Veterinary Hospital for almost a year and I am currently one of the Lead Registered Veterinary Technicians. I love helping pets, whether it’s an emergency surgery to save a life or going over the importance of vaccines. My favorite part of my job is that I make a difference in pets’ lives.

A typical day involves obtaining blood samples, triaging sick pets, taking radiographs, facilitating the DVM’s needs, and keeping the back on track with keeping up with the workload. I also spend time cleaning, filling prescription refills, checking on all hospital pets, and answering complex phone calls for concerned owners.

I love working with behavior problematic pets. Recently we had an 8-week old Pug who was acting a bit food aggressive. I took 30 minutes to show the owners how to train the Pup basic commands and to not reward her until we got that command down. When she came in for her next exam, it was so rewarding because the owner said that they have been training her for an hour a day and she knows Sit, Stay, Easy (when taking treats). They were so grateful and they even told me that their training time is called “Katie Time”. These are the moments I live for—I know I helped improve the bond between this owner and pet, and this is priceless.

I completed my Associate Degree at Carrington College in 2012 and had started working in the veterinary field about 5 years prior to going to school. I have also worked at Banfield Pet Hospital, Village Veterinary Hospital, and as a volunteer at the Stockton Animal Shelter.

Away from work, I love to read anything Science Fiction, especially by Stephen King. I also like to crochet, go fishing, and go to the beach. My husband and I play video games together, watch scary movies, and enjoy spending time with our pets.

Veterinary Assistants

Ashley Pattingale

Hi, I’m Ashley Pattingale and I joined the staff at Sierra Veterinary Hospital in March of 2017. I am currently a student at Modesto Junior College and I’m working on my Associate’s degree and becoming a registered veterinary technician.

I have always had a passion for animals and there has never been a point in my life without pets. I am a proud “fur-mommy” of 3 dogs and 2 horses. My Pit Bull mix is named Babu, and I have two Chihuahuas named Missy and Niko. I also have a BLM Mustang named Sweetie Pie and an American Paint Horse named Lexi. Before I started my journey into college and the veterinary field, I competed in Gymkhana equestrian events and barrel races. In the future, I’d love to work with large animals, but most of all I am just enjoying this journey and the wonderful friends and pets that I have come to know here at Sierra.

Carol Brighton

Hi, my name is Carol Brighton. I grew up on a farm on Roberts Island. Since my early childhood I have always had a special bond with animals. I started working at Sierra Veterinary Hospital four years ago as a kennel assistant. Because of the training the staff here provided for me the last two years I have worked as a Veterinary Technician Assistant. I feel I contribute to the clinic because of my unique approach of the way I handle the patients here. I have my own language I talk to them with. I also use soft verbal tones combined with gentle stroking to calm the patients down when they are afraid or in pain. Sierra Veterinary Hospital has given me the opportunity to pursue my dreams. Working here has been a joy for me.

Janeth Olivas

Cyleste Riego

Our Hospital Administrator

Tiffini Clark

Ms. Clark brings over 20 years’ Operations and Management experience to Sierra Veterinary Clinic.

While at Nordic Pharma, she managed the clinical, pre-clinical operations. She also led a team conducting research, managed the manufacturing, which included the design and scope of two clean rooms. Ms. Clark also managed HR, project management and regulatory operations. While part of Dr.’s Hospital Modesto she was the Operations Manager for the clinical research facility. During her time at Pharmacyclics, she was a team member that brought IBRUTINIB (a cancer drug) from discovery into Phase 3 clinical development and was an integral member of the business development team that executed $975M (BTK) transaction with Janssen Biotech, Inc. (IBRUTINIB). Ms. Clark was also an integral member of the business development teams that completed transactions with Novo Nordisk for the Factor VIIa inhibitor, PCI-27483, and the pan-HDAC deal with Les Laboratories Servier (ABEXINOSTAT).

While away from work she enjoys time with her daughter and her two grandchildren, and helps coach her grandson’s little league team. Ms. Clark has a toy teddy bear Pomeranian named Mufassa who has his own Facebook page (he’s kind of a celebrity). Tiffini looks forward to meeting all of the clients that Sierra calls family.

If you need to reach Tiffini please email her at [email protected]

Our Office Manager

Brenda Dockery

Hi. My name is Brenda and I have been here at Sierra Veterinary Hospital since October 2005. My favorite thing about being part of the Sierra family is the opportunity to meet so many wonderful people with love and dedication to animals of all kinds. This not only applies to the friendships I have made with my coworkers but also to all of you who visit us. I enjoy hearing all the humorous and heartfelt stories of our furry friends’ adventures and get great satisfaction in being able to offer comfort during the tougher times. I cherish the memories I have made here.

At home I have several furry friends of my own who keep me busy. Both of my dogs, Tina and Charlie, wandered in to Sierra looking for somewhere to go. Little did they know what they were in for when I adopted them and brought them home to a house full of cats. It’s taken some time for everyone to adjust but I think they have finally come to an understanding. My husband and I also have two kids of the non-furry variety who bring much love and laughter to our lives.

I look forward to many more years here at Sierra and the opportunity to get to know all of you better.

You can email me at [email protected].

Front Desk

Alexis Preciado

Hello, my name is Alexis and I have been at Sierra Veterinary Hospital since April 2015. I currently live in Stockton with my son Nathan and fiancé Anthony. We have our own mini zoo: Bullet, our Dutch shepherd, Bella, Link and Navi, our Bedlington terriers, Kyoko, Suki and Mr. Miyagi, our rescued Siamese cats, Spike, our adopted Russian tortoise and a saltwater tank.

Ever since I was little, I had a strong desire to be around and work with animals. I groom my three Bedlingtons at home and am currently in the process of showing Link and Navi. I like being able to work with an experienced team that provides great care for animals.

During my free time, I enjoy spending time with my family. I like to travel and see new places. I also love to draw and play video games.

Ysabella Vasquez

Yesenia Mena

Grooming Staff

Tasha John-Fournier

Sarah Willamson

Kennel Staff

Kristen Cappalla