A cow that survived a barn fire on Friday morning roams the grounds of a farm near Sarsfield. (Chad Pawson/CBC) Dozens of dairy cows have been killed in an overnight barn fire near Sarsfield in Ottawa's rural east end.

Fire fighters were called in shortly after 3 a.m to the farm located at 3750 Canaan Rd. near Colonial Road, about 40 kilometres east of downtown Ottawa.

Fire investigators said the fire started in the milking barn and spread to one of the three large silos located on the property.

It took 50 firefighters and 26 fire trucks to bring the blaze under control.

Fire officials said 70 cows perished in the fire, while another 50 survived.

The damages were estimated at $1 million.

By sunrise Friday, emergency crews could be seen putting out hotspots in a scorched silo.

Surviving cows blackened with ash were still roaming the property, as emergency crews and the farm owners attempted to round them up to be checked by a veterinarian.

Barn was brand new

The farm, owned by Henri Joly, his daughter Martine and son-in-law Christian, has been in operation for more than 50 years.

Relative Paul Paget said the barn had been built just two years ago.

"Yep, it's a brand new barn. So, it's all gone," he said.

Fire crews are still trying to determine if two silos on the farm will need to be demolished.

The milking equipment was not damaged, and officials believed it would be operational later Friday.

Fire officials have not released the cause of the fire.