Whether diagnosing complex animal diseases, teaching the intricacies of bacteriology, or wielding a hammer to build homes for the needy, UC Davis veterinary professor Richard Langan Walker Jr. was a dedicated scientist and kindhearted teacher and volunteer, recall friends and colleagues.

A January memorial celebration is planned for Walker, who died Dec. 1 in Bodega Bay, Calif., at age 56. Authorities are investigating his death as a probable suicide.

Walker was one of the founding faculty members in the California Animal Health and Food Safety Laboratory, a veterinary diagnostic lab operated by the UC Davis School of Veterinary Medicine for the State of California. At the lab, he diagnosed and studied infectious diseases that affect animals, especially livestock and poultry.

"In my role as state veterinarian, I had the opportunity to work closely with Rich Walker on many animal-health program issues, and we collaborated regularly," said Richard Breitmeyer of the California Department of Food and Agriculture.

"As the chief of microbiology at the diagnostic laboratory, he was the ultimate professional -- always going above and beyond to get us the information we needed and providing valuable advice on a multitude of animal health programs," said Breitmeyer, who attended veterinary school with Walker at UC Davis.

"Dr. Walker is greatly missed not only as a colleague and friend but also as one of the leading clinical diagnostic bacteriologists in the country," said Hailu Kinde, interim director of the California Animal Health and Food Safety Laboratory.

"He was a perfectionist and a person of high integrity, who performed his job with great commitment and pride," Kinde said. "He made tremendous contributions to our laboratory's bacteriology program from its infancy and as it grew to become a highly acclaimed laboratory."

Alex Ardans, a UC Davis veterinary professor and director emeritus of the diagnostic laboratory, said that Walker was nationally regarded as the ultimate authority in his area.

"He brought unique talents that guided the scholarly development of the lab's bacteriology section into one whose results are respected and trusted by producers and veterinarians, as well as animal health and public health officials," Ardans said.

"His keen intellect was especially evident in the section where he constantly sought approaches to ensure definitive results," Ardans said. "Rich quietly implemented modern molecular biology into daily use, allowing for rapid results and the discovery of new pathogens previously undetectable by conventional methods. His innovative approaches helped shape quality assurance programs throughout the nation's animal health diagnostic laboratories."

Bennie Osburn, dean of the UC Davis School of Veterinary Medicine, noted that, although Walker was a distinguished, nationally recognized bacteriologist, "he was always available to sit down at a microscope to solve the difficult individual case, where routine tests failed.

"However aside from his professional acumen, he was a wonderful human being, a true gentleman, a good friend to his colleagues and staff, and it is these personal attributes that truly distinguished him," Osburn said.

Walker was born April 22, 1952, in San Francisco and lived most of his early years in the Bay Area, where he graduated from Junipero Serra High School in San Mateo, California.

He received a bachelor's degree in microbiology from Colorado State University, Fort Collins, in 1974. At UC Davis, he went on to earn his doctor of veterinary medicine degree in 1980, a master of preventive veterinary medicine degree in 1984 , and a Ph.D. in comparative pathology in 1985, all from the School of Veterinary Medicine.

In 1971, Walker met DeeDee Hanna when they were undergraduates at Colorado State. The couple married in 1980 and established their first home in Atascadero, Calif. Their daughter, Mary, was born in 1991.

After completing his veterinary degree, Walker served as an adjunct professor of microbiology and immunology in the UC Davis School of Veterinary Medicine and worked part-time in veterinary hospitals in Vacaville and Cordelia. From 1985 to 1988, he served as an assistant professor in the North Carolina State University School of Veterinary Medicine.

Walker returned to UC Davis in 1988 as an assistant professor of clinical diagnostic bacteriology in the School of Veterinary Medicine, where he gained a reputation as a dedicated instructor and skilled scientist.

"He was an excellent teacher who received the highest ratings from veterinary students for his engaging lectures and was particularly effective in a one-on-one setting, where he could sift through the intricacies of a complex infectious disease processes," said veterinary professor Brad Barr, one of Walker's colleagues at the diagnostic laboratory. "He presented material in a simple, yet organized and interesting, manner that students could understand and appreciate."

Walker was a member of the American College of Veterinary Microbiologists and the American Association of Veterinary Laboratory Diagnosticians. He also was a member of the American Society for Microbiologists, American College of Veterinary Microbiologists, Conference of Research Workers in Animal Diseases and American Association of Veterinary Laboratory Diagnosticians.

His family noted that in addition to his professional interests, he enjoyed spending time with his family and rarely missed one of his daughter's many sports events. He loved all types of home construction projects and spent many happy hours roaming the aisles of Home Depot. When time permitted, he loved walking the beaches of Northern California and playing golf.

Veterinary professor Mark Anderson, a colleague at the diagnostic laboratory, noted that Walker had an "absolute passion and zeal for volunteer work outside of the laboratory," and regularly took vacation days to work building houses for Habitat for Humanity, an international nonprofit organization that helps needy people construct homes.

"At the job site, Rich was devoted to any task that needed to be done, even cement work or drywall," Anderson said. "He was always eager to help, making the job more fun for all the crew, raising our spirits with his friendly banter. Among the building crew he was known for his meticulous attention to detail and special skills with the finer points of trim carpentry."

In addition to his wife and daughter, both of Davis, Walker is survived by his father, Richard Walker Sr. of Aptos; sister, Kathy Hurley of La Selva Beach; brother, Andrew Walker of Carmel; and sister, Mary Smaby of Atascadero. He also leaves many cousins, nieces and nephews.

The family prefers that memorial donations be sent to Habitat for Humanity.