Megadairies Are Bad for the Environment

Cows on pasture can feed themselves and return their waste directly to the soil. Thousands of cows living in confinement, on the other hand, need their food and water delivered to them and their tremendous volume of waste must be removed. All these inputs and outputs take a serious toll on the environment.


Perhaps the most dangerous emissions from dairy cows are the tremendous amount of greenhouse gasses they produce, through belching and flatulence. A dairy cow is estimated to annually produce more than 330 kg of methane, a greenhouse gas at least 25 times more potent than carbon dioxide. In California, the top dairy-producing state, dairy cows account for 45 percent of the state’s methane emissions and 38 percent of its nitrous oxide, another extremely potent greenhouse gas. Globally, the top five greenhouse gas-emitting meat and dairy companies together produce annual emissions greater than ExxonMobil, Shell or BP.


Megadairies also produce an incredible amount of manure. A 2,000-cow dairy generates nearly a quarter of a million pounds of manure daily, or almost 90 million pounds per year. Manure is high in nitrogen and phosphorus; these are important fertilizers in proper amounts but are toxic in excess. Nitrogen breaks down into nitrate, which causes algae blooms and dead zones in lakes and rivers. Nitrate is a human health hazard when it finds its way into groundwater, with the potential to cause serious illness in babies and pregnant women and an increased risk of colon, kidney and stomach cancers in other adults. Dairy waste can also contain pathogens such as E. coli or drug residues; wells in some counties with high concentrations of megadairies have tested positive for endocrine disrupting compounds.

At megadairies, waste is generally stored in large open ponds, called lagoons, and sprayed onto cropland as fertilizer or injected into the ground. The lagoons release methane and are prone to leaks, releasing toxic liquid manure into ground or surface waters. In just one dramatic example from 2015, nearly 200,000 gallons of manure spilled from a storage tank in Oregon, flowing across private property, into a river and a bay. State officials had to close the bay to fishing for a week.

Leaks are not the only problem. The manure from that 2,000-cow dairy contains as much nitrogen as sewage from a community of 50,000 to 100,000 people. That’s so much fertilizer that the standard practices to dispose of it are simply inadequate. It is not uncommon for operators to spray it onto fields at rates higher than the soil can absorb or under conditions that aren’t ideal, causing it to run off into nearby waterways or seep into groundwater. In some regions, land values have increased due to demand by dairy operators for a place to dispose of their excess manure.


Megadairies also need a lot of water to produce milk. Milk is about 87 percent water, so cows have to drink several gallons of water daily when they’re milking. Flushing all the manure and keeping the milking equipment clean takes even more: estimates range from 30 to 50 gallons of water per cow per day. This is especially troubling considering the expansion of megadairies in dry states like New Mexico, Texas and California.

Even Wisconsin, a state with abundant water resources, is struggling with how much water dairies are drawing from aquifers. High-capacity wells that draw over 100,000 gallons per day are proliferating to feed large dairies and intensive crop production. As a result, lakes and rivers are drying up, impacting property values and tourism in the state.


Huge ponds of manure have an obvious downside for the neighbors: they stink. The odors from a megadairy can dramatically impact the health and quality of life of surrounding areas, making it difficult for local residents to go outdoors. Ammonia and hydrogen sulfide, two of the major pollutants from dairy manure, irritate the respiratory system and at high doses can even cause death. Particulates (tiny dust particles from dried manure), dust and feed have similar impacts. Cities in California’s San Joaquin Valley, near the heart of the state’s dairy country, have some of the highest rates of particulate pollution in the nation. Tens of thousands of dairy cows are chief among the contributing factors.

Some states have laws and regulations regarding odor and emissions from CAFOs, but at the federal level, the US Environmental Protection Agency (EPA) does not require farm operations to report air emissions. In 2018, the EPA exempted farms from the two environmental laws that require reporting releases of hazardous substances. The exemption was ostensibly to ease the regulatory burden for family farms, which have much lower emissions, but in practice, it shields industrial-scale dairies from any transparency about their air pollution and its burden on surrounding communities.


Some constituencies, from the dairy industry to some environmentalists, promote anaerobic manure digesters as an environmentally sustainable way to manage the huge amounts of manure generated by factory farms. Unlike an open lagoon, a digester is a closed environment, using microbes, heat, water and agitation to process the waste. The methane is captured for energy, and the other manure outputs are cleaned of phosphorus and pollutants, making them safer to spread as fertilizer. The federal government has invested millions in digester research and some states offer significant incentives for their construction.

Sounds good, but digesters do not make megadairies “green.” Despite all the public investment in the technology, a new digester costs anywhere from half a million dollars to $2 million, making them not economical to build or operate without significant subsidies. Instead of coming up with alternate solutions for how to store and manage animal waste, a “digester-first” model of managing manure assumes that huge manure lagoons are a necessary part of dairy production. Digesters need a steady high volume of waste to run efficiently, so the model of one megadairy supporting one digester further entrenches the large-scale confinement model of agriculture. The expenditure of public research and subsidy dollars in this technology also comes at the expense of similar investment in composting systems or pasture management.

Big Dairy Is a Bad Neighbor

The growth of megadairies has significant impacts on local communities, both in the regions where family dairy farms are closing and those where thousands of cows are being moved in.


The expansion of megadairies and resulting oversupply of milk is a major factor driving milk prices down and sending family dairies out of business. Squeezed by low prices, farmers are foregoing major purchases and cutting household expenses. Farmers still trying to hang on are sometimes unable to pay their electric bill or buy groceries. One dairy cooperative sent out information about suicide hotlines with the milk checks and calls to farmer support hotlines have increased.

In addition to the grave psychological toll this takes on the family, the lost income has a ripple effect throughout the local economy: as farmers cut back, the supermarket, clothing store, coffee shop and other businesses earn less.

Across all livestock sectors, small and mid-size farms spend more at local businesses than factory farms do. Large shipments of feed ingredients and medications lend themselves to volume discounts from faraway dealers, and a megadairy is likely to have a veterinarian, as well as mechanics and other specialists on staff, rather than using the services of the community. Numerous studies in the last 50 years show that factory farms result in lower relative incomes; greater income inequality and poverty; a less active Main Street; a lost multiplier effect from interrelated business activity and fewer stores.

The local economy loses out when family dairy farms close. And when a megadairy moves in, often receiving considerable tax breaks, its neighbors have to pay the real costs of the externalities that it offloads. In some dairy-intensive regions in California, Oregon and Wisconsin, the water table has become so polluted with animal waste that residents must purchase water to drink, cook and bathe with. In Wisconsin, property values of homes near megadairies have dropped by nearly 15 percent. Megadairies, often owned by companies headquartered in another state, are just as environmentally taxing an industry as coal or natural gas, polluting the land, extracting water and sending earnings out of the community.


Small farms generally rely on the family or sometimes a hired hand to milk cows and run the farm. Large dairies milking thousands of cows three times a day need considerably more labor, and megadairies will tout job creation as a benefit to the local economy. The reality, as on most farms, is that the majority of dairy workers are immigrants, not long-time community residents. Since the dairy industry is year-round, dairy operations are not eligible to hire legal workers through the seasonal H-2A guest worker program, so they turn to undocumented workers. In one survey of New York State dairy workers, 93 percent were undocumented. Fearing deportation, these workers are less likely to speak up or complain about poor treatment or conditions.

In many dairies, conditions are appalling. The work is physically difficult, smelly, dangerous and has long hours for low pay. Twelve-hour days are the norm, with only rare days off and no overtime pay. While dairies pay an average of $11 to $12 per hour, workers are usually hired only if they have a social security number (usually fake), and so they take home more like $9 per hour after taxes. (And, since they are not officially paying into the system, they will never reap the benefits of those taxes.) Workers are often provided housing, but it is often substandard and overcrowded, and many workers feel isolated in rural communities. Working with large animals, heavy machinery and slippery surfaces, injuries and infections are common and deaths sometimes occur. Over the course of five years in the 1990s, there were 12 documented worker deaths in manure lagoons.

How State Policy Supports Megadairies

Megadairies have been able to grow and operate recklessly thanks to lax state policy. In many states, lawmakers have passed laws and enacted regulations that make it easier for megadairies to operate, even in the face of local opposition. Promising jobs and economic development, which rarely materialize, operators often expect — and receive — tax breaks and other public subsidies to build their operations.

Here are a few examples:

  • Operators are not responsible for everyday leaks or seepage; this reduces costs for a megadairy. In Wisconsin, state regulations allow manure lagoons to leak up to 500 gallons per acre per day. Some lagoons are as large as four acres, allowing them to legally leak 2,000 gallons per day onto surrounding land and waterways with no responsibility for cleanup.
  • Many states offer tax exemptions that benefit factory farms over small or pasture-based farms. Small farms can take advantage of some of these exemptions, such as for farm equipment, land or livestock, but they are of greater benefit to large operations: the tax savings on 2,000 cows is greater than on 50. Across the country, tax exemptions are common on sales of supplies like livestock feed and bedding, pesticides and animal medications, and on construction and improvement of manure storage facilities and animal housing. These tax breaks are not designed for pasture-based farms, which grow most of their own feed, use fewer medications, and need housing and manure storage for their animals only in inclement weather — but they can mean huge savings for megadairies.
  • In Iowa, counties are effectively barred from contesting a new factory farm (or CAFO — concentrated animal feeding operation), due to a 1995 law that also opened the door to corporate ownership of livestock. The law protects all farms — even factory farms — from nuisance lawsuits and prohibits counties from adopting any zoning, public health or land use provisions that might restrict construction of a CAFO. While many farm states have retained their local control over factory farm siting, a few states like North Carolina have similar restrictions.

Fighting Megadairies with the Law

Since megadairies are supported by the law, communities across the country have also turned to the law to fight them. For example, in 2012, a US Environmental Protection Agency study showed that wells in a part of Washington State with several megadairies had extremely elevated nitrate levels, posing serious danger to the residents who rely on the wells for drinking water. When the state agencies responsible for regulating the dairies took no action, community groups sued the dairies in 2015 for violation of water protection laws. In a groundbreaking decision, the court ruled that the dairies were responsible for the water pollution and in a subsequent settlement, the dairies agreed to implement changes in their operations. Two years later, Washington State implemented new water protections for dairies with more than 200 cows.

In eastern Oregon, the debacle of one failed megadairy prompted proposal of broader legislation. Lost Valley, a 30,000-cow megadairy, was plagued with problems from the start; it opened with its waste management infrastructure only partially built and water rights secured only through a legal loophole. The operation racked up the most fines the state had ever issued to a dairy before declaring bankruptcy 18 months later, leaving 30 million gallons of manure awaiting cleanup. Area residents, tired of the slow pace of enforcement by state agencies and all too aware of the threat that megadairies pose to local economic and environmental health, worked with state lawmakers to introduce legislation calling for a temporary moratorium on dairies with more than 2,500 cows.

Similar measures have been proposed or introduced in states including Wisconsin, Indiana and Iowa, addressing not only megadairies but other new or expanded large livestock operations. The meat and dairy industries, which often promote the interests of mega-operations rather than the interests of independent farmers, are politically powerful, especially in so-called “farm states.” As a result, none of these moratorium laws has passed so far, but as more and more people from farm states to suburbs to big cities want a food system that’s good for themselves, farmers, workers, animals, local communities, the environment and public health, momentum will continue to build for these measures.

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