Eight cattle and one horse were killed Tuesday morning in a barn fire north of Wellesley.

Firefighters from Wellesley, St. Clements, Linwood and Baden were called to the Hessen Strasse barn shortly after 7 a.m. Tuesday.

According to acting Wellesley fire chief Steve Martin, there was a significant amount of flame consuming the upper portion of the barn when crews arrived.

The fire may have been smouldering for quite some time before it was noticeable.

Martin says a likely scenario involves the fire starting Monday night, as farm workers were using a thresher.

“When they were doing that, they thought they heard something going through the thresher which could have been a rock or a piece of metal,” he said.

Although the workers searched the barn, they didn’t find any signs of the object at the time.

When they returned to work Tuesday morning, they discovered smoke inside the barn and called 911.

Martin said that 10 cattle were kept in the barn, two of which were brought to safety.

No injuries to humans were reported.

Damage is estimated at somewhere between $300,000 and $400,000.

With reporting by Nadia Matos