A new study has found wintering barns on dairy farms will not necessarily be profitable, or better for the environment, but that's not why a lot of farmers want them.
DairyNZ and AgFirst have undertaken the study on the economic and nutrient loss impacts of building and running cow houses, basing it on five South Island farms that have the barns.
Dairy NZ senior economist, Matthew Newman said the study showed the barn can be either a potential money maker, or reduce the environmental footprint of a farm, but it was difficult to achieve both.
But he said the farmers generally invested in wintering barns for other reasons, including reducing the pugging of paddocks and better control of grazing management and feeding.
"Farmers that we visited and interviewed said it was more for management purposes, things like preventing pasture damage, improving conditions for cows and staff and reducing the reliance on winter grazing contracts.
"So it's about peace of mind and having control over the farm system."
But he said looking at the environmental side running a barn system would not necessarily lead to lower nitrogen loss.
The second stage of the study will involve nine Waikato barns and the final results will be completed early next year.