Harleen Dhillon Year: Senior Major: Biology Rebecca Neal Year: Junior Major: Anthropology and Religious Studies Sydney Endres Year: Junior Major: Dairy Science and Life Science Communication | Scenario | Abstract | Introduction | Literature Analysis | Materials and Methods | Results | Conclusion | Discussions | Limitations of Finding | Scenario The American Medical Association (AMA) approached a group of researchers at the University of Wisconsin-Madison requesting a detailed report on milk nutrition and the potential health benefits of milk. The AMA has also requested that the researchers assess the economical, environmental, and social sustainability of both a conventional and organic milk production systems in order for patients to make an informed decision about the milk they consume. The question is if there are more health benefits to milk produced following certain dairy production practices, as well as to analyze if one production method is more sustainable than another. Abstract Milk provides several key nutrients such as calcium, protein, fat, vitamins A, D, and B12. It is recommended that a person eats three servings of dairy every day as part of a healthy, balanced diet. Since milk is essential to our diets, it is important for consumers to know the nutritional contents in both conventional and organic milk to determine which kind provides the most health benefits. Both organically and conventionally practices produced milk that approximately had the same levels of nutrients, however, the fat content in the milk contained different levels of fatty acids, specifically the ratio between omega-3 fatty acids and omega-6 fatty acids. An LCA, meta-analysis of the scientific literature, and MIR spectroscopy were conducted to determine sustainability and fatty acid content of milk. The results indicated that neither conventional or organic milk production is more sustainable than the other. The conventional systems have fewer greenhouse gas emissions per unit of milk than organic systems. On the other hand, organic milk has a better ratio of omega-3 fatty acids to omega-6 fatty acids.It is difficult to give a recommendation of one type of milk over another since both have their own advantages and disadvantages. It is important for the patient to do their own research to make a fully informed decision. Introduction Milk is an essential part of our daily diets and it provides many key nutrients. It is recommended that a person consumes three servings of dairy every day as part of a healthy diet (USDA, 2016). A healthy diet has an optimal ratio of omega-3 and omega-6 fatty acids along with a healthy diet. The average American now consumes approximately four times more omega-6 fatty acids than humans in the past however the consumption of omega-3 fatty acids has not increased, and in many cases, has decreased. This recent trend tends to skews the ratio of omega-3 and omega-6 fatty acids in our bodies, which can impact who are genetically predisposed to diseases such as heart disease, stroke, arthritis, and asthma (Simopoulos, 2002). The decrease of omega-3s in our diet is partially due to the fact that meat and milk producing animals have gone from a diet based on pasture plants to grain, concentrates, and less fresh plant material (Tally, 2016). Many scientists advise drinking organic milk because it tends to have higher amounts of omega-3 fatty acids and lower amounts of omega-6s. The difference in fatty acids is because organic cows are required to get a certain amount of their food from pasture, leading them to eat more fresh plants and, therefore, their milk has a higher amount of omega-3 fatty acids. The controversy lies in this overgeneralization of health benefits because drinking organic milk alone is not necessarily large enough to make much of a difference in human health. If a person wanted to substantially increase their omega-3 intake from milk, they would have to drink gallons of organic milk per day. There is still disagreement between scientists on the optimal ratio between fatty acids is unclear (Chang, 2016). Likewise, the sustainability of the conventional and organic system must be done to determine long-term impacts of milk environmentally, socially, and economically. Different systems have different impacts on the environment and are accepted differently in the society. Society views the organic and conventional farms different and this can impact milk sales. Likewise, the difference in production impact cost of milk the consumer must pay. We hypothesized that while there may be differences in milk composition from various management practices, none are significant enough to make a large nutritional difference or environmental impact. The question is if there are more health benefits in certain dairy production practices as well as if one production method is more sustainable than another. Literature Analysis Many past studies have provided evidence and background knowledge helping to form hypotheses for this research project. Dairy foods are nutrient-dense and health-promoting foods that offer many health benefits. Researchers have observed the association of dairy with bone, cardiometabolic, cognitive, and digestive health in many cross-sectional studies. Due to the current evidence of its benefits, at least 3 daily serving of a dairy item is recommended by the dietary guidelines. This review concludes with a description of the current public health impact of dairy food research as well as recommendations for the food industry to formulate dairy foods that are both palatable and health-promoting for consumers (Hess, J. M., Jonnalagadda, S. S. and Slavin, J. L. 2016). From this research, we hypothesize that that milk has many nutritional benefits and must be researched to determine what specific nutrients can make one type of milk better than another. Over the last century, intakes of omega-6 fatty acids in Western diets have dramatically increased, while omega-3 intakes have fallen. The need for omega- 3 fatty acids have increased with recent finding indicating health benefits (Ruxton, C., Reed, S., Simpson, M., Millington, K, 2004). These trends have been impacting the ω-6/ω-3 intake ratio causing them to raise to nutritionally undesirable levels. We conclude that consumers have options to reduce their average ω-6/ω-3 ratios, thereby reducing risk factors for a wide range of health problems (Benbrook, C. M., et al. 2013). In addition, organic milk appears to yield more CLA and linolenic acid, which are assumed to be beneficial to health. Organic milk also contained less stearic acid, the major fatty acid in the omega ­6 (Tunick, M. H., et al. 2016). From this research, we hypothesize that the omega-6/omega-3 ratio is important in determining the nutritional content of milk and must be further researched. During a 12-mo longitudinal study, milk was collected from an organic and conventional dairy farms in the United Kingdom. All milk samples were analyzed for fatty acid content in regard to farming system type, herd production level, and other nutritional factors affecting the fatty acid composition. This source indicated that season, access to fresh grazing, or use of specific silage types could be used by producers to enhance the fatty acid content in milk (Ellis, K.A., Innocent, G., Grove-White, D., Cripps, P., McLean, W.G., Howard, C.V., Mihm, M. 2006). There has been an intensification of dairy production so there have been questions on whether the implementation of intensive feeding incorporating maize silage and concentrates is altering milk quality. Fatty acid and antioxidant profiles of milk were analyzed and found that the highest concentrations of nutritionally beneficial compounds were found in the low-input organic system. Grass-based feeding strategies such as pasture offer the potential to produce a distinguishable milk product quality (Kusche, Daniel, et. 2013). From these studies, we can conclude that there are ways to improve fatty acid content and measures can be taken to enhance this in milk production. There are ways to impact the fatty acid content in milk and must be examined further. Both organic and conventional production pathways impact the environment in different ways. Organic milk production reduces pesticide use in agriculture but this production form also requires more farmland than conventional production. The import of feed by conventional dairy farms often leads to an input of phosphorus and nitrogen into the system. The difference in production methods between the systems impact greenhouse emissions (Cederberg, C. 1998). Likewise, other researchers have examined the carbon footprint of confinement dairy systems in the U.K and U.S. and grass-based dairy systems in Ireland. The LCA calculated the carbon footprint per unit of milk and compared emissions from manure, feed coming into the farm, feed being grown on the farm, etc (O’Brien, D., Capper, J., Garnsworthy, P., Grainger, C., Shalloo, L. 2014). These studies have helped to hypothesize that differences in the conventional and organic system do cause different environmental impact. It is important to assess the sustainability of each system especially the environmental pillar to determine the long-term consequences of each system. It is also important to observe the social pillar of sustainability even though it is difficult to quantify. Research has been done to see how organic milk is popularized because of numerous different influences and norms in society. The norm‐activation‐model by Schwartz is used to predict and observed purchase behavior of organic milk. The purchase of organic milk is predicted by personal ecological norms, social norms, and perceived behavioral control. Personal norms are activated by awareness of need, awareness of consequences, perceived behavioral control, and social norms (Klockner, C. A. and S. Ohms 2009). Organic meat and milk differ markedly from their conventionally produced counterparts in measures of certain nutrients. The varying levels of fatty acids and the ability to lowering health risks were used in marketing in the organic milk. Whether these differences are scientifically backed up is disputed. Some scientists assert that organic and conventional foods are nutritionally indistinguishable, and others find significant benefits to organic. Many people who buy organic food do so not for a nutritional advantage, but because of environmental concerns and to avoid pesticides (Chang, K 2016). It is important to address the social influence and ideas when it comes to organic milk being healthier and this must be further researched. All in all, the literature review conducted helped to formulate hypotheses needed to enhance knowledge needed to conduct this research. Materials and Methods To assess the health benefits and sustainability of milk, a life cycle analysis was conducted to assess the outputs and inputs of each system individually. In addition, an MIR spectrometry and interviews were conducted to assess the nutritional component of milk and to determine health benefits. The objectives of the LCA (Ellis, K.A., Innocent, G., Grove-White, D., Cripps, P., McLean, W.G., Howard, C.V., Mihm, M. 2006) was to investigation the following: - identify which system has the largest environmental impact and to suggest which method is more sustainable -to collect data on feed used in the life cycle assessment (LCA) There are three key components of any LCA: -A functional unit is the measure of output from the system. In regard to this research, the FU is corrected for before leaving the farm gate. ECM is a correction factor used by the dairy industry and considers the fat and protein content of the milk. -The system boundaries define the processes included in the LCA. In regard in this LCA, the conventional milk production is characterized by 466,625 cows and the intensity in feeding has increased along with a rising milk yield. Organic milk system is characterized by 11,259 cows and more farms are transitioning to this method. -The co-product allocation refers to the process of allocating the environmental impact to other products that are inevitably associated with the production of the main product of interest. In the case of this research, the size of farm and quality of the feed impact two main outputs: milk and meat. In regard to the LCA, we examined the outputs and inputs of each system to determine sustainability. Likewise, we considered factors such as farm size and feed in assessing each system. In addition to examining LCAs and different research papers, we conducted interviews with University of Wisconsin-Madison Dairy Science professors Dave Combs and Heather White. These interviews gave us a better understanding of what is truly causes the differences in milk composition and gave us more information on the subject matter. Both Dr. Combs and Dr. White gave brief overviews of the history of the debate on which fats are considered healthier than others. Finally, we also conducted an MIR spectroscopy to analyze the omega fatty acid contents in milk. A mid-infrared spectroscopy examines molecules that differ in the combinations of functional groups and can be used to identify them and characterize their structure. Omega 3 and Omega 6 fatty acids differ in structure and an MIR spectroscopy is more generic than an NIR and so it is easy to obtain results. Results From the interviews, we found that the difference in fatty acids (omega-3, omega 6, and CLAs) shouldn’t be differentiated by organic versus conventional, but rather, a forage-based diet versus a pasture-based diet (White, 2016). The fats in forages and pasture are digested differently in the rumen, leading to different levels of conjugated linoleic acids (CLAs) and omega-3s in the milk (White et al., 2001). A pasture-based diet has 83% more CLAs than a forage based diet (White et al., 2001). Of all the fatty acids in milk, omega-3s make up less than one percent so it is not the best indicator of milk nutrition. A forage-based diet is around a half a percent of the fatty acids and a pasture-based diet will double that (White, 2016). The image below demonstrates the different ratios of omega 6/ omega 3 fatty acids in regard to region. Regardless of location, the conventional practice was larger than the organic. Also, there is variability in the ratio of fatty acids based on the location of the farm. This graph demonstrates how fatty acid content can be impacted by factors such as location and that conventional milk ratio is greater than organic milk. [Abbreviations: NW  =  Northwest, CA  =  California, RM  =  Rocky Mountain, TX  =  Texas, MW  =  Midwest, NE  =  Northeast, M-A  =  mid-Atlantic.] (Benbrook, C. M., et al. 2013) In addition, for the most part, conventional systems have fewer greenhouse gas emissions per unit of milk than organic systems. While the conventional systems have more inputs such as machinery to harvest crops and energy to house animals, the cows in these systems tend to produce more milk because the cows have a higher energy diet, and therefore fewer GHGs per unit of milk than organic practices. The image below demonstrated that overall conventional practices have more greenhouse gasses than organic practices. However, organic practices have more methane compared to conventional practice. Methane is the greenhouse gas that most are concerned about and the organic practices produce more. (Cederberg, C 1998) Conclusion Neither conventional nor organic milk production is more sustainable than the other or offers significant enough nutritional differences to make an impact on health. Greenhouse gas emission constitutes a large portion of dairy production’s environmental impacts in both organic and conventional systems. Although the USDA’s organic guidelines are designed to cater to people's’ social ideologies, actual dairy production methods do not necessarily result in the fruition of them. Therefore, the label “organic” does not necessarily mean production is more sustainable. GHG emission reduction practices would improve the environmental sustainability of dairy production and, in some cases, lead to higher levels of omega-3 fatty acids in the cow's milk. Since greater sustainability would result in a practice by practice basis, the best option for consumers is to know and understand the companies they are buying milk from. If increasing omega-3 fatty acid intake is a consumer’s goal, they are often more likely to achieve that by purchasing from pasture-fed cows. If a consumer has access to a farmer’s market, then farmers are present to ask about their practices and know what methods the farmer used to produce the milk. Discussions Because the difference in milk composition comes from a pasture-based diet versus a forage-based diet, we cannot conclude that organic milk is healthier than conventional milk. While organic milk does consist of a primarily pasture-based diet, this diet is not year-round and milk composition varies between species. In addition, a farmer has the ability to add CLAs to a TMR, which would then increase the amount of CLAs in the milk. People should not base their decision of purchasing milk based solely based off higher omega-3s and CLAs. It is hard to know the difference of fatty acids in each gallon of milk and the difference itself does not make a significant nutritional impact. Organic Milk vs. Conventional Milk: Sustainability or Lack Thereof We define sustainability as having three pillars: environmental, economic, and social. Conventional methods are modeled around producing the most food for the most people (Wattiaux: in class). Economic sustainability is the main concern because profitability is what drives the market. Farmers must make an income from milk so this pillar of sustainability gets the most focus. With the dimensions of USDA guidelines and affordability concerns, environmental and social sustainability often fall by the wayside. Organic methods are modeled on social values (Gomez 3/4/16). People want to feel good about their purchases, and people have personal opinions about protecting the environment, animal welfare, and their personal health such as omega fatty acid content. The organic market serves those desires in the people that can afford to buy organic products. Whether or not the outcomes always reflect interests is debatable, but in organic production systems, social sustainability is key because of the social perception that organic producer produce healthier milk. Arguably, the USDA organic standards are to improve environmental sustainability, while still providing organic food for a “fair” price, but ultimately organic farming attempts to draw consumers by their social ideologies. There is much overlap between their sustainability issues for both organic and conventional dairy production. Environmental: Greenhouse Gas Emissions Methane: In dairy production, 72% of greenhouse gasses are produced on the farm before reaching the consumer. Emissions are widespread in both conventional and organic farming (Wattiaux, Silva, Anderson, 2015). Methane’s impact on climate change is 25x greater than carbon dioxide’s making it a major concern for farmers. Methane is unavoidably produced via enteric fermentation, a normal part of digestion, and manure management practices (USEPA). Most methane is released when cows breathe out during digestion, and through chemical reactions in manure in anaerobic environments such as a sealed lagoon, or when it is liquefied and spread on crops. Research for methane mitigation are still relatively new and more research is needed to determine benefits. In regard to enteric fermentation, altering a cow’s diet like adding dietary oils, or feed promoting greater digestion in intestines instead of the stomach can decrease the amount of methane released (Center for Climate and Energy Solutions, 2009). Some dietary oils have a high percentage of omega-6 fatty acids, and others are higher in omega-3. If oil's high omega-3 fatty acids were added to a cow’s diet, the cow’s milk would then have a higher concentration of omega-3s as well (Newmark, 2014). Today’s cow’s diets have been modified to maximize milk production in part through making the dry feed more easily digestible (Grandin, 2015), which leads to less enteric fermentation. However, altering a cow’s diet in this way often means sacrificing the foliage that puts omega-3 fatty acids into the cow’s milk. On the other end, manure management also greatly affects methane production. Many large farms, organic and conventional alike, liquefy manure and store it in tanks or lagoons in order to spread it on fields as fertilizer. Both types of storage provide an anaerobic environment in which methane is released. One method of mitigating methane emission is burning methane for fuel or to generate electricity (Kowitt, 2016). On large dairy operations, methane produced by biodigestion of manure can substantially reduce the electricity costs. Burning methane results in carbon dioxide emissions, but those emissions would less than those produced from fossil fuels or generating electricity (Wattiaux). The USDA organic guidelines require cows to have a certain amount of pasture time, which contributes to increases in omega-3 fatty acid concentration in milk. During this time, solid manure decomposes in an aerobic environment. This environment reduces methane emissions, but releases more nitrous oxide, which has 300x the greenhouse potential of carbon dioxide pound for pound (EPA). There are no perfect solutions for the best methane mitigation practices in dairy farms, however, a balance between milk output and dietary adjustment seem to be promising. Nitrous Oxide: Nitrous oxide is released through the process of productions, transportation, and application of commercial fertilizers. In fact, the largest emission levels of nitrous oxide result from fertilizer use (EPA). Fertilizers are commonly associated with conventional farming methods. Organic farms are banned from using traditional fertilizers, however, organic farmers can fertilize the land with products certified “organic.” In both practices, most fertilizers are nitrogen-based, which emits high levels of nitrous oxide (Mcguire, 2009). Rain causes excess fertilizer to wash into lakes and rivers which can affect drinking water quality and ultimately flows down to the Gulf of Mexico where it causes massive algae blooms and subsequent dead zones (Shepard, 2012). One popular nitrogen-fixing process for creating fertilizers is the Haber-Bosch system. In this process, atmospheric nitrogen is pressurized at high temperatures and turned into ammonia and is then used to produce urea. It uses huge amounts of energy derived from natural gas, which is a nonrenewable resource, to create the fertilizer and produces large amounts of CO2 as a byproduct as well (Silva). Nitrous oxide emissions can be reduced by reducing nitrogen-based fertilizers and applying fertilizers more efficiently, however this does not always happen in practice. An alternative to nitrogen fertilizers is planting nitrogen fixing pasture plants such as clover, field peas, and other legumes as cover crops and/or for cows to graze on while simultaneously fertilizing the soil for the future. As well as adding stable nitrogen to the soil when cows are rotated out of the pasture and other crops are being grown. This practice involves cows consuming more raw vegetation, which increases omega-3 fatty acid content in milk (Neal, 2016). Today 82-94% of farms rotate their crops, but only about 3-7% of farms utilize cover cropping (Stone Barns Center, 2014). Although this practice may result in higher omega-3 fatty acids, many conventional farmers do not allow cows much pasture time. Cover crops can increase soil quality in the offseason, reduce costs for fertilizer inputs, and can provide an extra source of income by selling parts of cover crops as salad mixes and tea. Carbon Dioxide: Carbon dioxide is produced as a byproduct of fuel from machinery used in tilling, planting, fertilizing, watering, and harvesting fields, as well as spreading any pesticides and herbicides. When cows are indoors, the climate needs to be regulated by heating, cooling, and drying. In addition, pumps for milking, processing, and refrigeration milk all requires energy. The transportation of milk to retail and the facilities also burning fuel producing carbon dioxide. For the most part these inputs of carbon dioxide is shared by both conventional and organic dairy systems. Utilizing alternative methods of generating energy through solar, wind, or water power, as well as minimizing transportation of milk by selling more locally can reduce CO2 emissions. If a cow spends more time in the shade during pasture that can result in an increased omega-3 fatty acids in milk due to more grazing time as well as saving fuel on controlling the indoor climate. Carbon sequestration can also greatly reduce CO2 emissions. Removing tilling practices allows gradual bacteria consumption of carbon, instead of mixing all the carbon up allowing bacteria to utilize it all at once. This can deplete the soil of its nutrients so more fertilizers are needed the next growing season. On the other hand, less tillage usually results in higher herbicide usage to combat weeds. Cover-cropping prevents carbon from being released into the air, allows the soil to hold more water and nutrients, and utilizes carbon dioxide itself by removing it from the air. Social Social sustainability looks at two completely different systems in different ways. The organic dairy production model is directly related to the personal and social values of a particular group of their customers. The organic market, although growing rapidly, is much smaller than the conventional dairy production. There are not many farms that have incorporated organic practices because for generations, conventional methods were dominate in the market. Some organic farms are more sustainable than their conventional counterparts, but it is not always the organic guidelines that drive this difference of sustainability. Although the USDA organic standards could use some updating, the sentiment is still true that they promote and feed off of people's’ opinions toward the environment, animal welfare, and their personal health (USDA). Conventional dairy consumers also hold certain personal values, but conventional farming methods are made to provide more food available to a lot of people at a decent price. Many people cite as their reasons for purchasing organic products that they are better for the environment and emphasize the cow’s welfare. Organic dairy’s environmental sustainability is often as questionable as conventional dairies. Although, the USDA organic standards provide loose guidelines for better animal welfare, their looseness allows for a lot of variability. USDA guidelines state that organic cows must have access to the outdoors year-round, save for, during inclement weather, however, they do not specify what outdoor “access” entails or what is considered “inclement weather.” Cows are required to spend their grazing season in the pasture, but there are no guidelines as to what the grazing season is, what the pasture constitutes, or how much shade the cows should get in hot climates. Cows are highly sensitive to heat and produce less milk when overheated or when energy is spent cooling their bodies and walking around grazing. Because of this, climate concerns are often a reason cited by farmers for confining their cows to cramped indoor pens. It was noted that many farms who did follow USDA guidelines declared that their grazing seasons were very short, sometimes only two months long, in order to be able to keep their cows indoors for longer (Huffstutter, 2010). Because of this, in 2010, the USDA implemented a grazing season baseline so that cows had to be outside at least 120 days per year. This specific minimum time frame of 120 days ensures a certain amount of outdoor activity for cows and proves the importance of more specific guidelines if organic dairy production is to actually uphold consumers’ values as opposed to just being marketed that way. In order for organic dairy production to remain socially sustainable, it must continue to reflect consumers’ social priorities, even as the farms change or intensify. Economic Conventional and organic systems are different in that conventionally produced milk is the most affordable option on the market, whereas certified organically produced milk consumer must pay a premium. Because the higher cost of organic, most middle-upper class populations in wealthier countries often can afford this luxury. Many people hold social values regarding the environment and animal welfare, they are willing to pay the premium because organic is presented as the more sustainable option (Chang, K 2016). However, in countries like Peru, organic milk is rare because there is no market of people willing to pay more money for their milk (Gomez, 2016). People want to feel good about their purchases and organic systems market their product as healthier and more sustainable, people who can afford it are more likely to buy it. This market strategy gives organic an advantage compared to conventional milk, however since not everyone can afford organic, the general population will continue to purchase conventional. As the vast majority of organic milk production systems exist today, it is not sustainable enough to support the dairy needs of the majority of the world’s population. Organic milk is too expensive for most people to afford. It is important to be aware of the high prices included in buying organic and to balance one's budget as well as diet when making food choices. Patients can research specific producers of both the conventional and organic milk available to include in their evaluation. Limitations of Finding Much of the science and research surrounding the controversy of milk production and nutrition, particularly in regards to organic versus conventional methods, treat food systems as mutually exclusive. Abundant research has been done that considers milk as a singular component, however, some scientists such as Dr. Richard Bazinet, and popular voices like Michael Pollan hint to a larger idea of interconnectedness and dependence between food systems. It is difficult to isolate specific differences in nutrition between organic and conventional milk since most research focuses on how milk in general is beneficial to health. It often does not distinguish between organic or conventional milk but rather as milk as a whole. Likewise, most research mainly focuses on milk, however, as milk consumption among Americans has steadily fallen over the past few decades, many people obtain their daily serving of dairy through other products such as cheese and yogurt. The United States consumes more milk products such as cheese and yogurt than liquid milk so more research needs to be done to determine if obtaining milk through other sources impacts health benefits. The process of converting liquid milk into other products could influence the ratio of omega-3 and omega-6 fatty acids in the dairy product. When observing the sustainability of each system, different research projects find different results and analyze each system differently. Different studies draw different boundaries when conducting the LCAs, making it difficult to come up with concrete answers. There is variability between conventional farms and organic farms practices that vary by the environment they are within themselves making it difficult to come up with definitive answers as to which is more sustainable. Regardless of the limitation, a lot of research has been done to prove that milk is beneficial to health and can prevent numerous diseases. Many researchers have examined the ratios of omega 3 and omega 6 fatty acids in milk to prove that this ratio does have an impact on the nutritional content of the milk. Likewise, there have been LCA’s conducted and analyzed for both conventional and organic systems to demonstrate that there are differences in sustainability. The evidence from his study that is valuable because it demonstrates that regardless of the perception of organic milk, it is not necessarily more beneficial to human health or the environment. Next steps There needs to be more research done to break down the specific differences in the nutrition of organic and conventional milk. This study focused mainly on the difference in fatty acid differences between organic and conventional milk, however, other components such as protein content should be studied. Likewise, more research should be done to assess each production method to determine the inputs and outputs of each system. It is important to understand the whole picture when assessing the three pillars of sustainability by conducting another LCA specific to that region. 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