Dairy is a staple commodity in the diets of many Americans. Many cannot get through the day without reaching for a tall glass of milk or succumbing to the temptation of a bowl of ice cream. According to the US Department of Health and Human Services (2005), Americans consuming a standard 2,000 calories per day should have 2 to 3 servings of low-fat or non-fat milk products in a balanced diet (US Department of Health and Human Services, 2005). This indicates that dairy plays a critical role in the average diet, so it is widely produced and distributed. However, despite Americans consuming milk products at a high rate, many fail to consider the major environmental impacts of dairy production. The complete process of getting dairy to a consumer’s refrigerator has many steps including production, transportation, and storage that add up to a large ecological footprint. Milk production emits greenhouse gases at a rapid rate while simultaneously harming other ecosystems through eutrophication and deforestation. However, there are ways in which this footprint can be limited, such as through utilizing conventional production and using chemicals and cow fertility to increase milk yield. Because dairy production has many widespread environmental impacts such as the emission of greenhouse gases and the destruction of habitats, it is necessary to implement solutions that will limit these impacts and allow dairy to be produced sustainably.
Although dairy is one of the most popular food products in the United States, the process of creating it leaves a major ecological footprint. The primary way in which it impacts the environment is through greenhouse gas emissions. A study conducted by Rotz, Montes, and Chianese (2010) found that agricultural production results in 6 percent of the total greenhouse gas emissions in the United States. However, it contributes to 75 percent of the total nitrous oxide and 30 percent of the methane produced in this country. The pollution from each dairy farm analyzed ranged from 0.37 to 0.69 CO2 equivalent units per kilogram of milk produced. (Rotz, Montes, & Chianese, 2010) This study exhibits the idea that although agriculture makes up only 6 percent of the total greenhouse gas emissions in this country, it is still the top contributor of nitrous oxide while also producing a large amount of methane. These emissions need to be brought down so that every farm can start emitting closer to 0.37 CO2 equivalents per kilogram of milk. Another study by Phetteplace, Johnson, and Seidl (2001) found that methane (CH4) makes up about 52 percent of the total CO2 equivalents, and this methane is due to enteric fermentation and the manure of cattle. The sources of nitrous oxide (34 percent of the total emissions) include nitrogen excretion of the cattle, fertilizer application to animal feed, and nitrogen fixation by crops. Carbon dioxide (CO2) makes up the remaining 14 percent of total emissions, and its emission sources include fertilizer synthesis for cattle feed and transportation. (Phetteplace, Johnson, & Seidl, 2001) The issue with these greenhouse gas emissions is that they prevent heat and radiation from escaping the atmosphere, so the planet is warmed more rapidly. This warming results in a plethora of problems worldwide, including the destruction of habitats, rising sea levels, spread of disease, abnormal atmospheric conditions, and heat-related medical issues. To prevent these issues from intensifying, we must limit greenhouse emissions as much as possible, starting with those released during dairy production.
Milk production also harms the environment by crippling ecosystems and habitats directly through processes such as eutrophication and deforestation. Eutrophication is the process in which fertilizer or other contaminants run off into ponds or lakes, causing algal blooms. The sudden growth of algae absorbs oxygen out of the water, thus destroying the ecosystem and causing fish and other wildlife to die. A study by Filip and Middlebrooks (1976) analyzed the algal growth potential of cattle waste runoff into water wells. They found that the runoff contained high levels of nutrients such as nitrogen and phosphorus that could cause eutrophication (Filip & Middlebrooks, 1976). Therefore, cattle farms near bodies of water run a high risk of harming aquatic ecosystems. To prevent eutrophication, farmers should build walls to both prevent the manure from seeping into the water and allow them to collect it as a natural fertilizer. Another way in which dairy production can harm habitats is through deforestation. Raising cattle requires a lot of land, so as the need for pastureland increases, more forests will be destroyed so that cows may roam freely. A study based in Central America found that as the market for beef and dairy expands, so does the deforestation problem, because these markets need the extra land to raise their cattle (Nicholson, Blake, & Lee, 1995). Deforestation is a serious problem because tearing down forests and destroying land kills off populations of species and decimates ecosystems. Dairy production leads to the destruction of habitats and the death of populations, so it is crucial that humans find a way to produce their milk in a more sustainable way.
In order to combat the negative environmental issues caused by dairy production, it is necessary to find productive solutions that will maximize milk yield while limiting the amount of resources, cows, and land used. Switching all milk productions from organic to conventional and altering the hormones of cows to produce more milk will help limit the environmental impact. The first and most critical step that must be taken is using solely conventional dairy production rather than organic production. One study conducted by De Boer (2003) used life cycle assessments to analyze the environmental impact of conventional dairy production versus organic dairy production. The study found that organic production has just one environmental benefit over conventional production. It uses fewer fertilizers in its crop feed, so it has a lower eutrophication potential than conventional production. However, because organic does not use anything artificial to increase milk production efficiency, it requires a lot more cattle, land, and resources than conventional production. (De Boer, 2003) This means that the extra animals and resources will cause organic production to emit more greenhouse gases than conventional. Therefore, it will greatly reduce the environmental impact of dairy production if all operations are switched to conventional production.
Influencing the hormones of cows by treating them with safe chemicals and increasing their fertility will also allow farms to produce more milk with fewer resources, thus reducing the footprint of dairy production. First, administering cattle with safe chemicals will allow them to produce larger amounts of milk without harming the quality of their life. For instance, a study by Capper, Castañeda-Gutiérrez, Cady, and Bauman (2008) analyzed the beneficial impact of treating cows with recombinant bovine somatotropin (rbST), a chemical that can increase the efficiency of milk production. The experimenters were able to calculate the environmental impact by considering resource inputs and waste outputs. The experimenters evaluated the environmental impact of producing milk with one million cows treated rbST, and then compared that with the environmental impact of producing the same volume of milk with cows not treated with rbST. Because the untreated control group required a lot more cattle, they also produced a larger amount of greenhouse gases and higher levels eutrophication. The study stated that the chemical does not affect the livelihood of the cows at all. (Capper, Castañeda-Gutiérrez, Cady, & Bauman, 2008) Using recombinant bovine somatotropin is an easy way to reduce waste by limiting the number of cattle needed. Furthermore, the hormones of cows can be altered by increasing cow fertility. In one study, Garnsworthy (2004) created a mathematical model that correlates changes in cow fertility with milk yield and greenhouse gas emissions. This model was then used to find that when herds have lower fertility levels, they have higher greenhouse gas emissions, because when cows are unable to produce milk, more cows are required in the herd to meet the milk quota. These extra cows lower the fertility rate and increase methane emissions. The study stated that the best way to increase the fertility rate is by improving cattle nutrition. (Garnsworthy, 2004) Therefore, simply feeding cattle more nutritional food can raise fertility and reduce emissions. Altering the hormones in cows in healthy and sustainable ways is important because it allows producers to make the same amount of milk with higher efficiency, thus cutting the environmental impact.
Because dairy is a huge part of the American diet, it is critical that we minimize its environmental footprint so that we can continue to produce it sustainably. The production of dairy emits greenhouse gases such as methane, nitrous oxide, and carbon dioxide, and destroys habitats through eutrophication and deforestation. However, all of these effects can be limited by using conventional production rather than organic production and altering the hormones of cattle through safe chemicals like rbST and increasing cow fertility. These solutions allow farmers to produce the same (if not higher) levels of milk with far fewer resources, thus maximizing the efficiency of dairy production. These changes could limit the environmental impact of dairy and make milk production more sustainable as a whole.
References
- Capper, J. L., Castañeda-Gutiérrez, E., Cady, R. A., & Bauman, D. E. (2008). The environmental impact of recombinant bovine somatotropin (rbST) use in dairy production. Proceedings of the National Academy of Sciences, 105(28), 9668-9673
- De Boer, I. J. (2003). Environmental impact assessment of conventional and organic milk production. Livestock production science, 80(1), 69-77.
- Filip, D. S., & Middlebrooks, E. J. (1976). Eutrophication potential of dairy cattle waste runoff. Water Research, 10(1), 89-93.
- Garnsworthy, P. C. (2004). The environmental impact of fertility in dairy cows: a modelling approach to predict methane and ammonia emissions. Animal Feed Science and Technology, 112(1), 211-223.
- Nicholson, C. F., Blake, R. W., & Lee, D. R. (1995). Livestock, deforestation, and policy making: intensification of cattle production systems in Central America revisited. Journal of Dairy Science, 78(3), 719-734.
- Phetteplace, H. W., Johnson, D. E., & Seidl, A. F. (2001). Greenhouse gas emissions from simulated beef and dairy livestock systems in the United States. Nutrient Cycling in Agroecosystems, 60(1-3), 99-102.
- Rotz, C. A., Montes, F., & Chianese, D. S. (2010). The carbon footprint of dairy production systems through partial life cycle assessment. Journal of dairy science, 93(3), 1266-1282.
- US Department of Health and Human Services. (2005). Dietary guidelines for Americans, 2005.