With the start of the new dairy season only weeks away the recent death of an estimated quarter of a dairy herd near Cambridge, believed to have been caused by nitrate poisoning, will be a devastating tragedy for the farmers involved. While the number of dead cows is not known the financial and potential production loss will be significant blow.
There will also be a more personal loss; In spite of what is seen by many as the emergence of factory farming in recent decades, most dairy farmers still become attached to their herds. They have reared many of them from, calves and they handle them and work with them every day.
It is also very clear that the massive expansion and intensity of dairy farming since the 1990s has created a number of serious environmental and animal health issues previous generations of farmers did not have to deal with. They had natural nutrient and trace element deficiencies which they addressed by applying artificial fertilisers as early as the 1860s when the nutrient from ash from forest fires began to run out. Guano was then imported from islands in the Pacific for use on farms but there was still a lack natural of cobalt and other trace elements with the lack of phosphorus the most serious deficiency in most regions.
By 1880 superphosphate, a phosphorus-rich fertiliser, was being imported, local production started two years later and the world class New Zealand dairy industry was born and has continued to grow ever since.
From an initial 50,000 tonnes in 1885 the annual application of superphosphate has increased to more than three million tonnes today in addition to about 500,000 tonnes of nitrogen from urea. While experts and from farming, agricultural fertiliser companies and environmentalists argue the details too much artificial fertilisers and too many cows, and other ruminant animals are the root cause of many of our pollution and animal health problems through the overload of nutrients in soil and adjacent waterways.
The disposal of milking shed effluent was always a problem even when the average herd was less than a couple of hundred. Today herds of a thousand or more are not uncommon and the national dairy herd is about 6.5million. The disposal of effluent on that scale has become an industrial science and most dairy farms now have efficient systems of storage and recycling.
The massive increase of nutrients into the New Zealand ecology however remains a major threat to the environment. Nutrient monitoring, emissions limits and unenforced regulations have done very little to reduce the overload and nitrate poisoning is only one of many resultant animal and human health threats.
Nitrate poisoning will also cause blue baby syndrome in humans and is caused by high nitrates levels in drinking water. In cattle and infant humans high nitrate levels decrease the ability of blood to carry oxygen and the condition, if not quickly treated can be fatal. Last year the Ministry for the Environment reported that nitrogen levels at over half of monitored river sites were getting worse. In areas of pastoral farming 72 per cent of sites had worsened, while only28 per cent improved. While some environmental groups want a total ban on the use of synthetic nitrogen on New Zealand farms, orchards and market gardens, slowing down these successful export industries will be much easier demanded than done.
The ugly truth that no one really wants hear however is that, if the New Zealand environment is going to remain safe for human life, we have probably reached the limit of pastoral farming of ruminant animals and the use of artificial fertilisers.
Some will say we have well exceeded that limit and we need urgently return to a more basic and natural form of farming before the environmental damage becomes irreversible. Others will claim there is too much scaremongering about environmental issues and that we still need to produce food at a higher rate than ever before.
There is some truth to both arguments if we are discussing the same thing but too often we are not.
In spite of the growing organic farming movement there is no possibility of ever returning to subsistent farming even if we only produce enough to feed New Zealand.
When opponents to reduced cattle numbers and fertiliser use talk about food production are they not really talking about profits? The two are legitimate reasons to be in farming but they have very different incentives and outcomes and we already produce enough to supply an estimate 34 million people who dont live here.
We could farm efficiently, although less profitably, with vastly fewer animals and almost no artificial fertilisers but no one has yet to come up with the incentive to do so.