Beef and dairy are the biggest guzzlers of water in U.S. food production. Cows are thirsty, water-intensive animals: Whether they’re fed by supplemental feed crops or grazing in pasture, it takes an immense amount of water to raise cattle. In addition to inefficient water use, grazing in arid landscapes and enormous amounts of water pollution also hurt water sources. Despite overwhelming evidence showing ecological damage to biodiversity and healthy habitats, much of the dialogue around water use and drought does not delve deeply into the impacts of cattle, water use and wildlife.
Globally, beef cattle use one-third of the water used for farmed animal production — the largest contribution to the sector’s water footprint. Overall U.S. beef production uses 21.2 trillion gallons of water annually. A cow eats 25 pounds of feed to produce a single pound of edible beef, making it an extraordinarily inefficient and water intensive source of human food. In drought-plagued California, feed production for animals consumes 34% of all irrigated water, and alfalfa alone consumes more water than any other crop in the state. Alfalfa and other water-intensive forage crops are often used to supplement the diets of grass-fed and dairy cattle.
Grazing cattle also take an enormous toll on U.S. water sources. The water footprint of grass-fed beef can be as much as 5 times greater than beef from cattle confined in feedlots. Water footprints are based on how much feed is consumed (feed conversion efficiency), what kind of feed is consumed (feed composition), and feed origin, which presents varying local climates, soil condition and agricultural practices. Meanwhile cows raised for dairy may take 30-50 gallons of water per day, equivalent to 5 pounds of water for every pound of milk produced. (Read more about feed conversion inefficiencies.)
Where feedlot cattle have a stronger impact on pollution and consumption of surface and pumped groundwater (what’s called “gray” and “blue” water) grass-fed cattle have a larger impact on rainwater (called “green” water). Blue water scarcity and water pollution mean industrial agricultural systems place greater pressure on ground and surface water than grazing, which uses less blue water.
However, it’s not accurate to claim grazing cattle use less water than industrially produced cattle. Feed conversion is more efficient in industrial systems (3.7 times more feed is required in grazing systems). In simple terms, grazing cattle use less blue water than factory farms, but significantly more green water.
Cattle excrete 120 pounds of manure each day per cow, about as much as 30 people. In intensive, factory-farmed systems, manure is spread on fields or collected in manure lagoons. In primarily grazing systems, cattle distribute manure through pastures, grasslands, forests, and riparian wetlands, which is a major contributor to water pollution in U.S. waterways. Both systems pollute groundwater from chemical runoff. But scaling grazing systems up to meet current beef demand would overrun our landscapes and waterways.
Cattle feces and urine deposited in or near watersheds contributes to nitrogen, phosphorus, and other nutrient concentrations in streams and can affect bacteriological quality of stream water. Livestock trampling and grazing near streambanks may increase bank sloughing and stream sedimentation, while reducing riparian vegetation needed for food, shade, and cover for fish and aquatic ecosystems.
In grass-fed systems, cattle are raised longer than the intensified feeding in factory-farm systems. In well-managed, small-scale systems with smaller herds, grazed in rotation away from watersheds and vulnerable ecosystems, manure can be nutrient-rich and promote crop diversity and soil health.
However, historically, grazing has led to trampled and polluted streams. Regional differences also have different capacities for livestock production, and this, too, complicates the broad claim of scaling up production. What works for cattle grazers in the riparian Northeast cannot work in the arid Southwest, for example. Furthermore, transferring all beef production to pasture-raised systems would stretch native ecosystems beyond capacity.
Riparian ecosystems, where land and streams meet, are vulnerable to grazing damage because of soil compaction and excretions and reduction of riparian vegetation that regulate water temperature and provide habitat for fish and wildlife. Cattle manure flows into aquifers and elevates nitrogen levels, creating “dead zones” that kill fish and contaminate drinking water.
A study of the Hart Mountain National Antelope Refuge in the U.S. Great Basin makes the impact of cattle in the West very clear and demonstrates the benefits of removing cattle from nonnative riparian ecosystems (Ripple 2015). The study assessed the ecological changes after decades of cattle removal and found that channel widths decreased by 64% and eroding banks decreased by 73%. Researchers found a 90% decrease in the amount of bare soil (P\0.001) and a 63% decrease in exposed channel (P< 0.001) as well as a significant increase in the cover of grasses/sedges/forbs as well as rushes (389% increase) and willow (388% increase).
Although regional differences in landscape and ecosystem, stocking rate, climate and management style are important, it remains clear that grazing cattle are generally at odds with the recovery of vulnerable wildlife and ecosystem integrity.
Cattle grazing reduces stream flows via channel and soil damage and increased surface runoff; it breaks down stream banks and increases sediment that reduces pools and salmonid survival; and increases water temperatures via vegetation, soil and channel damage.
A 2015 study of freshwater ecosystems, for example, demonstrated a substantial temperature difference in ungrazed vs. grazed aquatic systems, greatly affecting overall ecosystem health and species survival. Cattle trample and remove vegetation that provides shade and habitat within these ecosystems. The removal of this vegetation and the degradation of the riparian zone due to livestock activities harms cold-water salmonids in the West, for example, especially native golden trout, a species at risk due to degraded habitat and rising water temperatures.
Cattle seek out water, forage, and shade in riparian areas, resulting in trampling and overgrazing of streambanks, soil erosion, loss of streambank stability and declining water quality. This creates reduced habitat for riparian plant species, coldwater fish and other wildlife. Competition is worsened in the arid West, where in drier, hotter conditions with fewer water sources grazing cattle have damaged 80% of streams and riparian areas.
Other ways aquatic ecosystem integrity is harmed by cattle grazing include:
Water quality: Grazing increases nutrient concentrations, protozoa and bacteria. Sediment, turbidity and water temperatures increase while dissolved oxygen levels decline.
Cattle grazing has a significant impact on native wildlife. Water troughs and ponds created for cattle also create breeding habitat for the mosquitoes that carry West Nile Virus. The virus has been shown to infect sage grouse, a key indicator of overall ecosystem health.
Grass-fed cattle rely on grassland, rangeland and pasture forage that also takes a significant amount of rainwater. In a warming climate and pervasive drought, this creates further conflict with native wildlife in the West along with conflict over natural waterways. In California, tule elk, native to the public lands of the Point Reyes National Seashore, are in unfair competition for natural water resources with heavily subsidized cattle producers who graze their cattle operations in this national seashore. Tule elk are an ecologically critical part of these wild lands and many have died from a lack of access to water from fencing or have been killed by park employees on behalf of private cattle grazers. Native wildlife “thirsting” to death to prioritize highly scarce and valuable water for livestock is not sustainable.
Forage production for animals like cattle and sheep is the largest consumer of western water and the primary justification for dams that prevent fish migration and change water flows. Sixty fish species in the western United States are at elevated risk of imperilment or extinction due to flow depletion, and nearly 90% of these are primarily due to irrigation of cattle-feed crops.
What many consumers may not know is that “grass-fed” and “pasture-raised” cattle can sometimes still be supplemented with forage or graze irrigated pastures. Even in California, water for irrigated pasture and alfalfa are still the biggest consumers of water. Alfalfa, the primary feed crop for dairy cattle, is highly water intensive. Drought-prone California, meanwhile, is the biggest producer of dairy and alfalfa (75% of which is used for dairy).
By creating water scarcity, irrigation withdrawals and water developments impact endangered and threatened species. Groundwater pumping reduces the flow of springs and seepage, endangering mollusk and amphibian species due to the loss of wet meadows. For example, frogs must sometimes resort to artificial features like stock ponds because so much of their native aquatic habitat has been degraded, diminished and destroyed by livestock.
Similarly, when water is diverted from a stream for irrigation or to provide water to livestock, it means less habitat in the stream for aquatic insects and fish, as well as other wildlife dependent on those species like swallows, who eat insects, and bald eagles and otters, who eat fish. For example, a 2020 study found that 60 fish species in the western United States are at high risk due to water withdrawals primarily for irrigation of feed crops for cattle.
California, a state with the largest population and biggest domestic water use in the West, produces one-third of the nation’s vegetables and two-thirds of all U.S. fruits and nuts. Even with its boom in almond production and historic drought, most agricultural water in the state goes to cattle and sheep; water for irrigated pasture and alfalfa are the biggest consumers of water.
With a rising global climate and the impacts of this warming already seen and felt in the United States, especially by more marginalized communities, we must think seriously about how we produce food into the future. Food security around the world is going to be dependent on water conservation. As water becomes increasingly scarce, agricultural water is being taken from communities that don’t have enough drinking water. Foods that demand the most water will need to make way for smarter, more just and equitable food systems that provide more food to more people in a sustainable way, even amidst a rising climate and drought.
As demonstrated in the chart below, animal agriculture is overwhelmingly the biggest user of water:
In the U.S. West and Global North, the overconsumption and production of beef and dairy have dire consequences. Even with adaptations to grazing practices that may mitigate some of the soil damage or greenhouse gas emissions of beef production, we can’t overlook the price of water use and pollution when it comes to grazing cattle. Especially in the arid West, it simply does not make sense to continue to produce water-intensive foods like beef and dairy, in neither feedlot nor grazing scenarios. At current rates of consumption and production, at least a 50% reduction in dairy and a 90% reduction in beef in the United States is recommended by 2030 to transition to more water-efficient, drought-resilient and environmentally sustainable agriculture.
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