Abstract: An improved, stakeless livestock trailer includes sidewalls and a front wall constructed of stacked and interlocked extruded tubular members. In addition to forming the walls, the tubular members also form the exterior framework of the trailer, allowing a modular floor system to be attached directly to the sidewalls. The tubular members themselves have a unique tongue and groove interlocking structure which allows an adhesive to be inserted therebetween and which provides interior voids for excessive adhesive to collect during assembly. An improved gooseneck design eliminates the large support I beams required by prior art gooseneck designs, thus increasing storage space and/or increasing the clearance of an overhead storage compartment.