Dr. Maurice S. Shahan, 78, a retired Agriculture Department official, died July 22 at his home in Southold, N.Y.

He had served as the first director of the department's animal disease center on Plum Island, N.Y., from 1953 until retiring in 1962.

Before that, Dr. Shahan had been with the Agriculture Department here for 20 years, specializing in a animal disease research.

In addition to establishing the Plum Island center, the only one of its type in the country, Dr. Shahan also had served as codirector set up to eradicate Hoof-and-mouth disease in Mexico in the 1940s.

One of his most important research findings led to the development of a vaccine for the control of equine encephalomyelitis.

Born in Kearney, Neb., Dr. Shahan graduated from the School of Veterinary Medicine of Colorado A&M University. He later received an Honorary doctorate from Colorado State University.

He had been a member of the Conference of Research Workers on Animal Diseases of North America, the American Veterinary Medical Association and the U.S. Livestock Sanitary Association.

Dr. Shahan had served on numerous committees of the National Academy of Science.

He is survived by his wife, Gladys, of the home; a son, Robert, of California; a sister, Mrs. L.S. Parsons, of Arizona, and a brother, Gerald, of California.