Drivers on Highway 401 in Mississauga, Ont., were forced to navigate around a herd of cattle late Friday and into Saturday after the animals got loose from a transport truck that struck a barrier.

The truck driver was hauling the cattle when he hit a guard rail in the westbound lanes approaching Hurontario Street around 11:30 p.m., according to OPP Sgt. Kerry Schmidt. The driver was transported to hospital with what paramedics described as "moderate" injuries.

VIDEO: Cows roaming all over Highway 401 near Hurontario St in <a href="https://twitter.com/hashtag/Mississauga?src=hash&ref_src=twsrc%5Etfw">#Mississauga</a> after the truck they were in struck the bull nose & split the side open. Driver to hospital, non-life threatening. <a href="https://twitter.com/IAFF1212?ref_src=twsrc%5Etfw">@IAFF1212</a> and <a href="https://twitter.com/OPP_HSD?ref_src=twsrc%5Etfw">@OPP_HSD</a> worked to corral the cows. <a href="https://twitter.com/MississaugaFES?ref_src=twsrc%5Etfw">@MississaugaFES</a> <a href="https://twitter.com/firechieftim?ref_src=twsrc%5Etfw">@firechieftim</a> <a href="https://t.co/DuONklEhcw">pic.twitter.com/DuONklEhcw</a> —@JeremyCohnTV

The collision split one side of the trailer, offering a path of escape for about a dozen cows and steers inside. A number of the animals were injured in the crash and had to be put down.

It took police and firefighters several hours to round up the loose cattle. (Jeremy Cohn/CBC)

Provincial police were forced to close the express lanes in both directions as officers and firefighters worked for several hours to corral all of the loose cattle. The closures lasted nearly seven hours before the highway reopened.