Crews continued to battle hotspots on Thursday at a London dairy farm where a fire broke out Wednesday night.

Fire crews were called to the scene after OPP officers spotted the blaze around 9:30 p.m. on Old Victoria Road, north of Wilton Grove Road.

Crews were able to contain the fire to the building housing 4,000 bales of hay.

Firefighters were immediately met with a challenge when they arrived, as no fire hydrants were on site. So, trucks were called into transport water from over a kilometre away.

Highway 401, along with many surrounding roads were closed for several hours.

London fire platoon chief Doug Shannon says officials closed the roadways not only because of thick smoke, but because of concerns that guide wires securing a nearby radio tower to could snap and cause the tower to collapse

Luckily the fire didn’t claim the lives of any of the 1,000 cattle on site, though there is a risk they were exposed to smoke inhalation. No other injuries are reported.

Fire officials tell CTV News that damage is estimated to be around $2 million. Just the bales of hay are estimated at around $400,000.

The Ontario Fire Marshal's Office has been called in to help determine the cause of the blaze.