Robert W. Gilbert, 48, general manager of the Springfield division of Shenandoah's Pride Dairy, died Monday at the Medical College of Virginia Hospital in Richmond after a long illness. He suffered from a kidney ailment.

Mrs. Gilbert also was assistant general manager and assistant secretary of the parent company. The Valley of Virginia Cooperative Milk Producters Association, which had headquarters in Harrisonburg.

He started work with the association in 1953 as a field employee and laboratory technician. He then served as plant manager at the Harrisonburg headquarters from 1956 to 1961.

Transfered that year to Northern Virginia as division general manager, Mr. Gilbert was responsible for planning and designing a new plant in Springfield to replace and consolidate facilities in Alexandria, Falls Church and Manassas.

Born in Roanoke, he grew up on a farm in Campbell County. He worked his way through Virginia Polytechnical Institute by milking the school herd of 45 Holsteins twice a day. He earned a bachelor's degree in dairy husbandry in 1950.

Mr. Gilbert worked on farms in Amelia and Patrick countries, studying cattle breeding experiments.

He was a former president of the Virginia Dairy Products Association of the board of directors of the Dairy Council of Greater Metropolitan Washington. He also had served on the board of directors of the National Dairy Council.

Mr. Gilbert was treasurer of the Advertising and Promotion Agency for the Mid-Atlantic Milk Marketing Area from 1972 to 1977. He had been a member of the FairFax Chamber of Commerce and former president of the Alexandria Sertoma Club. He belonged to St. John's United Methodist Church.

He is survived by his wife, Betty and a daughter, Cynthia, both of the home in Springfield; a son, Robert, and another daughter, Linda Hughes, both of Springfield; his parents, Mr. and Mrs. Saylor S. Gilbert, of Lynchburg; a brother, Saylor Jr., of Brevard, N.C., and a granchild.

The family suggests that expression of sympathy may be in the form of contributions to St. John's Church, to be divided between the memorial fund of the church and the Medical College of Virginia.