Russell E. Davis, 75, an animal nutritionist who was assistant branch chief of the Agricultural Research Center at Beltsville, died June 20 at Carriage Hill nursing home in Silver Spring following a stroke.

Dr. Davis was a native of Leesburg, Ohio. He earned a bachelor's degree at Wilmington College in Wilmington, Ohio, and a doctorate in agricultural chemistry at Ohio State University.

He joined the Department of Agriculture here as an assistant biochemist with the bureau of animal industry in 1931. He later worked as a nutritionist and animal husbandry researcher and specialized in the feeding of beef cattle. He was named assistant branch chief in 1963. He retired in 1967.

Dr. Davis was a member of the Optical Society of America, a fellow of the American Association for the Advancement of Science and the American Society of Animal Science, and a 50-year member of the American Chemical Society.

He had been a trustee and an elder of the Hyattsville Presbyterian Church. He was a member of Berwyn United Presbyterian Church at the time of his death.

He is survived by his wife, Mary R., of the home in College Park; a son, William R., of Upper Marlboro: two daughters, Mary Kay Penn, of Gaithersburg, and Martha E. Aisquith, of Mitchellville, Md.; a brother, Robert Q. Sr., of Palo Alto, Calif.; eight grandchildren, and two great-grandchildren.