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There are more cows in Vermont than the state’s agricultural land can accommodate under current practices, according to a new study from a UVM research fellow. But a promising solution to the problem would place a financial burden on struggling dairy farmers.
The study recommends “precision feeding” as a promising approach to reduce dairies’ rate of water pollution without reducing herd sizes. However, some Vermont counties, including Franklin and Orleans, may simply have more cows than the land can handle.
“We have in many parts of the state a herd size the land cannot support,” said Jon Erickson, a UVM professor who co-authored the study.
“I hope [the study] is yet another wake-up call, that despite our best efforts … in many senses the efforts are missing the target: We need to make some tough decisions around herd size and location,” Erickson said.
Authored by UVM’s Gund Graduate Fellow Michael Wironen, of the Rubenstein School of Environment and Natural Resources, the study focuses on phosphorus, and its accumulation in Vermont soil over the past 90 years.
The study looks at how much of the element is imported into the state, how much is exported through products like milk and meat, and how much remains in the state, either bound to the soil or polluting surface waters.
“While feed is imported and milk exported, manure remains in Vermont,” the study states.
Imported feed has allowed Vermont dairy farming to dramatically increase in efficiency, and while this drives down the price Vermont farmers can demand for their milk, the increased production costs the state in other ways, Wironen said.
“The places producing [Vermont’s milk] and bearing the water-quality costs are not the places benefiting from cheap milk,” he said.
Vermont farmers have for nearly a century imported far more phosphorus than they require to grow their crops and feed their cattle, Wironen’s study found. Since 1925, farmers in the state have imported more than 1,000 metric tons of excess phosphorus each year.
Much of that phosphorus finds its way to Vermont’s public bodies of water, where phosphorus pollution in recent years has nourished toxic blooms of cyanobacteria, an organism sometimes referred to as blue-green algae that has discolored some of the state’s biggest lakes.
One of the most surprising findings, Wironen said, was the fact that Vermont imports most of its phosphorus not in commercial fertilizer, but rather in the form of grain used to feed cattle. Since 1981, most of that excess phosphorus has been contained in feed, not fertilizer, he found.
It’s often believed that much of Vermont’s phosphorus pollution results from commercial fertilizer, which farmers apply to grow primarily corn for livestock feed. But that’s not the case, Wironen found.
Instead, the study suggests that most of the state’s agricultural phosphorus pollution comes from cow manure. And herds today are producing far more manure than ever before, according to Wironen’s study.
Cows produce so much manure these days because farmers gormandise their herds: between 1950 and 1997, Vermont dairy farmers increased the quantity of grains and supplements they gave each cow from 803 kilograms per year to 2,635 kilograms per year, according to the study.
This indulgence, in turn, dramatically boosts milk production: between 1925 and 2012, dairy farmers increased their per-cow milk production by 400 percent, the study found.
At the same time, by feeding cows grain instead of hay, and by importing that grain, farmers could concentrate their cattle inside structures and dramatically reduce the land required to support a herd.
As a result, Vermont agriculture takes up less than a quarter of the land area that it once did — from covering more than 60 percent of the state in 1935 to less than 15 percent of the state in 2012, according to the study.
The state’s total milk production has doubled over the same period.
Despite all these gains in efficiency and reductions in land use, Vermont still sells some of the most expensive milk in the country, the report states.
That fact complicates one of the few good solutions outside of reducing the number of cows in Vermont, which would be a tax on cattle feed, Wironen said.
If cattle feed cost more it would encourage farmers to “precision feed” their animals — giving them no more than the animals need — and would reduce the excess quantity of phosphorus the state imports annually, he said.
The vast majority of Vermont milk is exported, and in those markets most farmers can command only a set price determined in part by states whose dairies benefit from vast economies of scale that don’t exist in Vermont, Wironen said.
Milk prices today are dismally low, with Vermont farmers reporting that the current cost of production is higher than what they can fetch on the market.
This means a feed tax to encourage precision feeding “would basically impose a cost on farmers that they have no hope of recouping,” Wironen said.
The next best thing would be for the state to better track how phosphorus makes its way into, around and out of the state, he said. For instance, the state should make available information from farmers on soil tests, fertilization rates and other conditions that scientists can use to figure out where in Vermont the worst rates of pollution are occurring, he said.
Farmers are already required to acquire and maintain that information, in the form of a nutrient management plan. However, both Agriculture Secretary Anson Tebbetts and the Senate Committee on Agriculture Chairman Bobby Starr, D-Essex-Orleans, have sought to hide these documents from the public, including scientists.
The public also does not have access to state records of cattle feed imports, which the Agency of Agriculture, Food and Markets has been required to collect since 2016.
Agency of Agriculture spokesman Scott Waterman said that nobody at the agency was available for comment on Tuesday.
“This study points to a lot of missing information that we don’t have,” Erickson said. “We’re making a lot of decisions by throwing darts at blank boards, when we actually know a lot more about the board than we’re led on to believe.”
Wironen’s study will be published in May in the academic journal Global Environmental Change.
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