The Collaborative International Dictionary of English v.0.48:

Dogcart \Dog"cart`\, n.
   A light one-horse carriage, commonly two-wheeled, patterned
   after a cart. The original dogcarts used in England by
   sportsmen had a box at the back for carrying dogs. Dog day

WordNet (r) 3.0 (2006):

dogcart
    n 1: a cart drawn by a dog