He did not have an exact figure yet.
His focus was on assuring the physical and mental wellbeing of his staff and welfare of his animals, he said.
It was something he would "not wish on anybody".
"Some people don't think so, but farmers are very close to their animals, that's why a lot of us do it.
"The real tough part is they are all individuals. Farmers know their livestock, kids take them to calf clubs. The emotion that strikes them is the same as if they were your pets.''
He has farmed since 1956 and the event was a first for him.
Since the fire he had been "absolutely inundated'' with neighbours seeking to help out.
He did not need to take them up on their offers as he had a big team, and Mycoplasma bovis fears made it difficult for others to come on to the farm.
The building had two pens still standing, but he did not know whether it was salvageable.
The fire was extinguished with the help of two fire appliances, from Oamaru and Glenavy, backed by water tankers from Glenavy and Weston.
The firefighters, some of who used breathing apparatus, had left the scene by 8.20pm.
Fire and Emergency New Zealand spokesman Dan Reilly said when firefighters arrived at the scene people were using diggers to remove hay bales from the building.
The fire was not being treated as suspicious.
They would likely know more about the cause within the next week.