I've walked past this statue of a draft horse pulling a cart many times and just recently looked up its name and history. It part of a public art installation by the British artist Sarah Lucas and is called "Perceval."
On the publicartfund.org website I read, "The piece is a replica of a popular knick-knack that adorns many mantelpieces in the UK; the subject matter reflects Lucas' predilection for reexamining everyday objects in unusual contexts. The installation of Perceval at the entrance to Central Park, where horse drawn carriages line-up daily to offer guided visits of New York, plays off of its urban and pedestrian surroundings."
It was at Fifth Avenue and Central Park South until recently when it ended its run. I'll have to go back and see what they've got there now.