Huron County OPP were called to a crash on Donnybrook Line at Belfast Road in Ashfield-Colborne-Wawanosh last Tuesday afternoon around 5:30.
They arrived to find an SUV colliding with a horse and buggy.
No one was hurt but the horse suffered serious injuries and had to be put down.
An investigation revealed that the SUV was travelling at highway speed when it rear-ended the buggy.
Drivers of motorized vehicles are being reminded to slow down when approaching a horse-drawn carriage or any slow-moving vehicle on the road.