Convert from truss to gamma

Unit Definition (truss)
The truss is a traditional weight unit, generally equal to 4 stone or 56 pounds (about 25.4 kilograms). The truss was used primarily for measuring hay. In 1795, Parliament specified that a truss of hay should equal 56 pounds for old hay or 60 pounds (about 27.2 kilograms) for new hay.

Unit Definition (gamma)
The gamma is an informal metric unit of mass equal to 1 microgram (µg).