About 29 cattle were killed this morning after a tractor trailer rolled over on Highway 20 between Saint-Hyacinthe and Drummondville.

The truck carrying about 35 cattle flipped over and landed in the median at about 2:30 a.m.

About a dozen of the cattle were thrown from the trailer and police had to shoot several of them in order to prevent danger to motorists.

Cattle-dead-truck-crash-highway-20

Several of the injured cattle were removed from the crash site after they were euthanized by veterinarians. (CBC)

Police said the remaining cattle inside the truck will be euthanized by a veterinarian and six of the cattle are expected to survive.

It appears the driver, who suffered minor injuries, fell asleep at the wheel.

Police are still investigating to determine the cause.

Highway 20 eastbound is open to traffic and one lane on the westbound highway is open.