From industry to charity, the lasting legacy of Dr. Mark Morris Sr. on small animal medicine

Updated June 16, 2023

This year marks the 75th anniversary of Hill's Pet Nutrition and the Morris Animal Foundation (MAF). A facilitator of the creation and success of both groups was one man: Dr. Mark L. Morris Sr.

From therapeutic diets and pet nutrition to companion animal research and organized veterinary medical associations, the veterinary profession has been profoundly impacted by the work of Dr. Morris.

As a young veterinarian, he opened one of the first hospitals for the practice of small animal medicine and during his career helped establish standards for veterinary hospitals, equipment, and staff.

"Dr. Morris's contribution to small animal veterinary medicine is enormous," said Dr. Kelly Diehl, senior director of science communication at Morris Animal Foundation. "Not only was he a pioneer of small animal practice but he was instrumental in the founding of the American Animal Hospital Association, and he served as president of the AVMA."

"We were founded by a veterinarian and have the profession close to our hearts," said Dr. Jolle Kirpensteijn, chief veterinary officer of Hill's. "This celebration is not only for us but for all veterinary professionals in the world."

To celebrate the 75th anniversary, Hill's held a global ceremony in May for employees. Also, in recognition of the momentous occasion, Hill's is offering a free continuing education (CE) course to all veterinary professionals in collaboration with the World Small Animal Veterinary Association (WSAVA) (see sidebar), and is releasing an upgraded version of Dr. Morris's first diet: Hill's Prescription Diet k/d.

The early days

Dr. Mark Morris Sr. was born on November 18, 1900, in Adams County, Colorado. He earned his veterinary degree in 1926 from Cornell University. While working in private practice, Dr. Morris started to research how to improve animal health, applying diagnostic and treatment protocols used in human medicine to his patients. In the late 1920s, he built the nation's second hospital for the practice of small animal medicine in Edison, New Jersey.

A few years later, he led a group of seven veterinarians who founded the American Animal Hospital Association (AAHA) and served as its first president in 1933. At that time, veterinary medicine was largely devoted to agricultural animals and few veterinarians treated pets exclusively. These visionary doctors wanted an association "to focus on promoting high-quality standards for the rapidly evolving sector of small animal private practice through accreditation and other initiatives," according to AAHA.

Dr. Morris also served as president of the AVMA from 1961-62. He gave an address at the AVMA Annual Convention in 1961 in Detroit that was both prescient and pragmatic. Dr. Morris pushed for greater recruitment of veterinary students and members of the AVMA, standardizing admission requirements to veterinary schools, mentorship of recent veterinary graduates, research to combat foreign animal diseases, and having members get involved in local, state, and national politics.

Dr. Morris also outlined a vision for the AVMA to take on more public relations strategies, work closer with allied organizations in other health care fields, increase its budget, and establish a permanent home for the Association, which finally happened in 1970 when the AVMA decided to construct its own office building in Schaumburg, Illinois.

"As you know, progress requires plans, blueprints, guidance, and money. We have the plan. We have the blueprints to build the structure. From you must come the money and the judgement," he said. "With all humility, I pledge myself to the building of the structure for the future of our profession."

"One of the honors of serving as AVMA president is building on the work of the extraordinary men and women who have served in this position in the past, and learning about the remarkable, lasting contributions they have made to the profession and the AVMA," said Dr. Lori Teller, 2022-23 AVMA president. "Dr. Morris's commitment to advancing animal health and nutrition, and his unwavering belief in the importance of small animal medicine, continue to inspire us. We stand on the shoulders of giants like Dr. Morris in our continuous quest to advance veterinary medicine and serve our profession with the same foresight, energy and commitment he exemplified throughout his life."

Creating custom pet food

He is best known, however, for his work developing pet foods for the dietary management of diseases in dogs and cats. The catalyst happened to be the Great Depression. During this time of deep economic depression, Dr. Morris noticed an unusually large number of dogs with kidney disease.

He finally identified the cause of the problem: Because people couldn't afford as much food, table scraps normally fed to dogs were being replaced with inexpensive dog foods containing low-grade, meat by-products, MAF information states. Thus, diets with a lot of poor-quality protein were causing widespread canine kidney failure.

By 1939, Dr. Morris was working with Rutgers University to create his own dog food mix to treat kidney disease in his patients, and the formula was a great success. One of those patients was Buddy, a guide dog who was suffering from kidney failure but recovered after eating Dr. Morris's pet food.

Encouraged by Buddy's owner, Morris Frank, to produce the mix in greater quantity, Dr. Morris joined with the Hill Packing Company in Topeka, Kansas, to can his pet foods. That pet food became the precursor to a restricted protein diet for canine kidney patients called Hill's Prescription Diet k/d Canine, first marketed in 1948 as a partnership with Burton Hill and Hill Packing Company of Topeka, Kansas.

The success with this product inspired Dr. Morris to study other dog and cat diseases, such as liver and heart diseases, pancreatitis, and obesity. Along with his son, Dr. Mark Morris Jr., he developed additional breakthrough Prescription Diet products designed to treat unhealthy dogs and cats, later adding the Science Diet brand, specifically formulated to meet the nutritional needs of healthy dogs and cats.

"Perhaps his greatest contribution was recognizing the role that diet plays in health–not just in the maintenance of good health but the role it could play in the treatment of disease," said Dr. Diehl. "The plethora of diets for pets, the amount of research invested each year in small animal diet research–so much can be traced back to Dr. Morris making a prototype of Hill's k/d diet in his home kitchen."

Elevating the importance of research

Another one of Dr. Morris's important contributions to animal health was the recognition that more research was needed to improve the health and well-being of animals, Dr. Diehl said.

He understood that funding was a major obstacle for some veterinary scientists and so he decided to set aside one-half cent per can of food toward an endowment for a new animal health charity. That charity, Morris Animal Foundation, was formed in 1948–the same year Dr. Morris's pet food mix was first marketed as Hill's.

Today, the foundation is the largest nongovernmental sponsor of companion animal health studies, having invested more than $149 million toward more than 2,945 animal health studies at veterinary colleges around the world to date.

Later, during the 1950s, Dr. Morris worked with the nation's veterinary schools to encourage the teaching of clinical nutrition as part of the standard curriculum, work that was continued by his son, Dr. Morris Jr. Expanding on the four original prescription diets developed by his father, Dr. Morris Jr. also helped develop hundreds of new products, providing innovative and quality diets for not only dogs and cats but also for many other species, from ferrets to seals.

Carrying on the family legacy, Dr. Morris Jr. became a worldwide authority on companion animal nutrition and was an active mentor and teacher of others in his field. He is the co-author of "Small Animal Clinical Nutrition," the standard textbook on clinical nutrition used to educate veterinarians throughout the world.

Maintaining his legacy

The Mark Morris Institute (MMI), which was established in his honor at the time of Dr. Morris Sr.'s death in 1993, continues his work in promoting education of veterinary clinical nutrition. The majority of MMI's resources go toward its College Teaching Program in North American and Caribbean veterinary schools, which provides evidence-based small animal nutrition education through courses and services free of charge to veterinary schools.

Today, Hill's Pet Nutrition maintain its dedication to making pet nutrition a cornerstone of veterinary medicine. From their 180-acre Pet Nutrition Center in Topeka, Kansas, the company analyzes pet food ingredients to ensure optimum nutrition for the 450 dogs and 450 cats that live at the center. The animals, or "pet partners" as the company calls them, take part in preference tests for taste, smell, and kibble size, to help Hill's develop foods that are not only nutritious but that pets enjoy.

Hill's continues to invest in research and infrastructure, such as its Small Paws Innovation Center specifically designed for small dogs. The company also continues to create and launch new products, such as Prescription Diet Gastrointestinal Biome, which was launched in 2019 and targets dogs and cats with chronic GI issues, or Prescription Diet Derm Complete, which was launched in 2021 to address food and environmental allergies.

Earlier this year, the company launched Prescription Diet ONC Care, a nutrition line specially designed to support pets with cancer. The first therapeutic food on the market specifically developed to meet the needs of oncology patients, the company describes it as a highly palatable, easy-to-chew food that also includes Hill's proprietary blend of prebiotics.

Dr. Margot Vahrenwald, the current president of AAHA, which Dr. Morris founded in 1933, said his legacy, particularly his focus on nutrition for small animals, is fundamental to how veterinary medicine is practiced today.

"I don't think that there is a small animal veterinarian globally who has not been touched by that legacy, whether the diagnostics we commonly use, targeted prescription pet foods, ongoing research in clinical nutrition, or the standards of care and excellence from the American Animal Hospital Association," she said.

Dr. Vahrenwald is also the owner of Park Hill Veterinary Medical Center in Denver and recalled a visit she made to Hill's Pet Nutrition Center.

"The care and dedication of the entire staff at all levels was evidence of Dr. Morris's intention to successfully use clinical nutrition to enhance the health of cats and dogs in sickness and in health," she said.

Hill's has plans to celebrate the 75th anniversary throughout the year while the Morris Animal Foundation is celebrating its 75th anniversary this month with June 15 declared as Morris Animal Foundation Day by Colorado Governor Jared Polis.

A version of this story appears in the August 2023 print issue of JAVMA.