Escalating international prices for dairy products have prompted an understandable reshaping of New Zealand's dairying landscape. So rapid has been the expansion from the industry's Taranaki and Waikato heartland that today, more than a quarter of the country's cows are in the South Island.
Included in this process has been the establishment of dairying in locations that, often because of climatic chill or scarcity of water, are far from ideal for the practice. One of these is the Mackenzie Basin, a land of tussock traditionally devoted to sheep farming.
To make dairying more than marginally profitable in such areas requires techniques not usually associated with this country. Hence the large-scale stall-based farming proposed by three companies that want to set up 16 new farms in the basin.
According to their plans, nearly 18,000 cows would be housed in "cubicle stables" 24 hours a day for eight months of the year, and 12 hours a day from November to February. Such practice is common in Europe and the United States, where it is underpinned by large-scale subsidies.
But it represents a significant departure from this country's tradition of grass-fed, free-range dairying based on its comparative advantage in climate and clover.
That tradition has earned New Zealand strong plaudits internationally for environmental friendliness and animal welfare.
Dairying is seen as fitting snugly with the country's clean, green brand. It is on this ground that the Green Party has led the charge against what it describes as "industrial factory dairy farming".
It predicts "immense harm" to that brand if the three companies are granted resource consents by Environment Canterbury. Weighing in behind the Greens have been the Agriculture Minister, who says he is worried about the proliferation of dairying in fragile environments, and Fonterra, which considers stall-based farming inconsistent with New Zealand's reputation.
"We will be watching carefully to see if the farms are able to comply with the regulations governing animal welfare and sustainable land use," it says. Of these concerns, perhaps only that related to animal welfare is considerably overstated.
Most such operations in the US and Europe do not treat animals badly, even if the cows do not have the freedom offered by pastures. Cubicle stables are not comparable to sow crates.
Nonetheless, increasing concern, both locally and globally, over farming practices cannot be ignored. The outrage earlier this year over television images of pigs in sow crates and the increased preference for free-range eggs says much about the consumer appetite.
Internationally, anything smacking of inhumane practice will be seized on by those keen to dent this country's image in its biggest markets. Critics overseas would doubtless also query the need and motivation for stall-based dairying in a country so rich in pasture land.
They would ask why so much scarce water from the Mackenzie Basin's braided rivers was being used for this activity, and question the long-term impact of both this and the effluent run-off from this type of farming. They might also question the rigour attached to the pricing of that water and the emissions from these operations.
In an era of such environmental sensitivity and with all the talk about food miles from New Zealand's global competitors, these are not idle concerns. Our comparative advantage has sponsored a reputation that should not be jeopardised lightly.
Essentially, the Mackenzie Basin is not suitable for dairying. Something as alien as stall-based farming may make it possible and profitable. But that is not where this country's best interests lie.