Dozens of cows perished in a fire at a dairy farm near Aylmer, Ont., Wednesday that destroyed several large buildings and took more than seven hours to bring under control.

Damage is estimated at $3 million.

Fire officials say the flames destroyed office buildings, the milk house and the milk parlor at Walker Dairy, as well as accessory buildings, but firefighters were able to save some of the operation.

The director of fire services for Malahide Township, Brent Smith, said 78 cattle weren’t able to escape the flames but firefighters and others on the scene were able to save about 850 cows.

“We know the ones that were lost in the fire we could not get out, but certainly there are others that … may succumb to the smoke from the fire. So (the number of dead cattle) is highly likely to climb,” said Smith.

A huge effort was made staff at the farm to corral the cattle in other areas when the flames broke out. Firefighters assisted with the rescue mission when they arrived on the scene.

Elgin County OPP spokesperson Const. Troy Carlson said officers had to put down some of the injured cows.

The cause of the fire is still under investigation, but Smith said it was likely the result of an electrical failure in the milk house.

“All of the electrical – which is very high voltage – comes into the building and all the electrical panels are located within there.”

He said the fire is not considered suspicious and that the Ontario Fire Marshall’s office has indicated its satisfied with his department’s analysis of the cause.