Last week, guest poster Joanna Samuelson Lidback explained that milk – conventional or organic – is safe to drink and why her family has chosen to remain a “conventional” farm. Today, we have another guest post, this one from Kirstin Hendrickson, on health and environmental problems with large-scale dairy farming.
You may be wondering why on earth we’re spending so much time talking about milk on a parenting blog. That’s a good question, and I admit that we’ve gotten a bit off topic. However, I think that Americans, and especially our children, are far too disconnected from their food supply. It is important for us to understand where our food comes from and the impact of our buying decisions – and to pass that understanding on to our kids. Kirstin gives us more food for thought on organic vs. conventional milk, and I hope that the respectful discussion of these issues continues.
Organic Versus Conventional Milk: Health Issues And Environmental Perspectives
By Kirstin Hendrickson
Ah, the organic versus conventional debate. It’s easy to get overwhelmed by information flying around — much of which seems to change on a daily basis — with regard to whether organic is safer and healthier, or a scam directed at fearful parents. There are some important health issues associated with organic foods, but I don’t want to get into those in this post. Instead, I want to address all the reasons to buy organic food — specifically, organic milk — that AREN’T associated with individual health. Or at least, aren’t ostensibly associated with individual health.
A small, conventional dairy farm like the one described by Joanna Samuelson Lidback in this recent guest post on Science of Mom sounds lovely. Joanna paints a picture of an idyllic family farm, and I think it’s terrific that she and her family are raising dairy cattle so cleanly, despite forgoing the organic label. Hats off to Joanna. If everyone raised dairy cattle like she does, there’d be little reason to consider organic milk.
Joanna’s farm is the exception in the U.S. dairy industry, and a rare exception at that. Cattle raised like hers make up only a tiny fraction of the U.S. dairy herd. The vast majority of U.S. dairy cows are housed in animal feeding operations (AFOs), and specifically in concentrated animal feeding operations (CAFOs) (see D. Imhoff, ed [book], FoodAndWaterWatch.org). As defined by the Environmental Protection Agency (EPA), an AFO is an animal housing operation that confines animals for more than 45 days per growing season, and does not produce vegetation within the confinement area. The narrower term CAFO refers to an AFO that: a) meets the size requirements for a large CAFO (by definition a number of animals that produces significant environmental pollution); or b) meets the size requirements for a medium or small CAFO and has been determined a significant contributor of pollution. Both AFOs and CAFOs are designed to be efficient means of producing a large quantity of animal product (meat, eggs, milk) on a relatively small plot of land (note the use of the word relatively; AFOs/CAFOs can be huge, but they take up far less land per animal than pasture would). By EPA definition, then, both AFOs and CAFOs are crowded, and CAFOs are major sources of environmental pollution. The EPA defines a factory farm as a CAFO, for instance, if animals come into direct contact with surface water and/or animal waste is piped into surface water. In addition to the CAFO being a significant environmental polluter, the conditions are also ideal for spreading disease. This is one of the reasons that animals housed in CAFOs are routinely dosed with antibiotics (see, for example, Raymond et al, Sawant et al, and Penn State College of Agricultural Science). The antibiotics necessitated by the very nature of a CAFO are the first major issue associated with conventional dairy farming. Milk from dairy cows, regardless of how they’re raised, is free from antibiotics. However, antibiotic overuse — meaning use of antibiotics in a prophylactic sense and as necessary for treatment of diseases spread through unnecessary husbandry practices — is promoting the development of antibiotic-resistant bacteria. While any conventional farming operation that utilizes excessive quantities of antibiotics can promote antibiotic-resistant bacteria (see, for example, Walczak et al), CAFOs are notorious breeding grounds for such species, which then spread outward (see, for instance, Chapin et al, Gibbs et al, Langford et al, Makovec et al, Pruden et al, Sapkota et al, Thames et al, Wells et al). If a person becomes infected with one of these antibiotic-resistant bacterial species, the resulting infection can be quite difficult to treat. Some examples of existing bacterial species that display antibiotic resistance include: Clostridium difficile, which causes severe diarrhea; Escherichia coli (E. coli), which causes severe — and sometimes fatal — food poisoning; Pseudomonas aeruginosa, which causes pneumonia and septic shock (among other things); Salmonella, which causes severe food poisoning; and Staphylococcus aureus (of the MRSA infection). Because conventional operations including CAFOs promote the development of antibiotic-resistant bacteria that then proliferate in the environment, it’s not necessary to have contact with or consume a conventionally-raised animal or product to be negatively impacted by these practices.
Another major issue associated with CAFOs is that they produce tremendous amounts of concentrated environmental waste. While it can be argued that a certain number of livestock animals produce a certain quantity of waste-per-head, the concentrated nature of the CAFO increases its impact. Pastured animals in relatively low concentration produce manure (poop), which fertilizes the soil and is part of the natural nitrogen cycle. In low concentrations, poop is good for the soil. The manure produced in a CAFO, however, is exceedingly concentrated. There’s far too much of it for the land to absorb, so it runs off into the surface water (lakes and rivers) and leeches into the groundwater (aquifers that feed municipal supplies and wells). Nitrogen-containing compounds in the manure that are healthy for the soil in appropriate concentrations — including nitrates and nitrites — are very unhealthy in high concentrations. Excess nitrogen in the water affects its pH (acidity), killing fish and other aquatic organisms. It also promotes the excessive growth of algae, which in turn robs the water of oxygen and suffocates fish. The nitrogen spreads through the atmosphere and contributes to acid rain, which kills trees and aquatic life. Nitrogenous chemicals in drinking water are toxic, particularly to very young children; consumption of water high in nitrates and nitrites causes blue baby syndrome, which can be deadly. Then, too, there’s the fact that the nitrogen species in manure runoff (recall that by definition, CAFOs produce significant manure runoff in excess of what the land can absorb) are greenhouse gases. These gases contribute to global warming (Koneswaran et al, VandeHaar et al).
There are also animal welfare issues associated with CAFOs. First off, crowding leads to increased likelihood of animal injury and incidence of disease (Gurian-Sherman, D.). Animals housed in CAFOs are denied the pasture access that would be natural to such stock, and are fed modified diets that have major ramifications for animal health, as cows are not native consumers of grain (Pollan, M.). Absence of grass aside, the diet of the CAFO dairy cow leaves a lot to be desired. While the FDA no longer allows the feeding of cattle byproducts (cow brains, spinal cords, etc) to cattle, it’s perfectly legal to feed this meat waste to chickens (Sapkota et al). It’s then legal to turn around and feed what’s euphamistically called “chicken litter” — a mixture of feathers, feces, discarded chicken feed, and so forth that’s swept off the floors of chicken coops — to cattle. The majority of conventional cattle are therefore unwitting cannibals. Further, they eat a reasonable quantity of chicken feces. Does this affect the milk? No, not really. However, it’s a morally questionable way to treat an animal. Furthermore, it increases the likelihood of spreading “mad cow disease” — bovine spongiform encephalopathy, or BSE — which is contracted by a cow when it consumes the contaminated meat of another infected cow. A case of BSE in a California dairy cow was reported just last week. Humans can get a fatal illness called Creutzfeldt-Jakob disease if they consume the contaminated meat of a BSE-infected cow, regardless of how well the meat is cooked. While a “mad” dairy cow isn’t a risk to humans in a direct sense — the disease can’t be transmitted via milk — any BSE in U.S. cattle increases the risk of the infection spreading, and CAFO practices provide the perfect environment for transmitting BSE from one cow to another because of the de facto cannibalism.
Moreover, many conventional operations, CAFOs included, use the hormone recombinant bovine somatotropin (rBST) (though use has been falling somewhat in recent years). Joanna and previous Science of Mom guest poster Dr. Katie Schoenberg both pointed out (correctly) that there’s no difference between the milk produced by a cow given rBST and a cow not given rBST. A meta-analysis (a study of studies) of the effects of rBST revealed that rBST administration does increase milk production, and makes very little difference in milk composition (Dohoo et al). There is no reason to believe that rBST in milk has any effect whatsoever upon humans. Is milk from rBST-administered cows safe to drink? Absolutely. But whether milk from rBST cows is safe to drink isn’t the only issue. Despite the fact that two isolated studies, cited by Dr. Schoenberg in her guest post, showed no increase in the risk of mastitis in cows receiving rBST, there are a great number of studies that show the contrary. The Dohoo meta-analysis revealed that, looking at the combined data of 53 different studies, cows treated with rBST are 27% more likely to develop mastitis than untreated cows. Not only is this an animal welfare issue (as anyone who has ever had mastitis knows), it also contributes to the overuse of antibiotics and the development of antibiotic resistant bacterial species.
Despite the fact that milk from rBST-treated cows and that from cows not treated with rBST is nutritionally equivalent, the same can’t be said for conventional versus organic milk. The vast majority of conventionally farmed dairy cows — including all CAFO cows — are fed a diet comprised largely of grain (see, for example, Eastridge et al, Jenkins et al, VandeHaar et al). The cows do not graze on grass, as pastured, organic farm dairy cows do. This produces a difference in the fatty acid (fat) profile of the milk from the cows. Compared to conventionally farmed cow milk, organic cow milk is significantly higher in omega-3 fatty acids (Ellis et al), which are anti-inflammatory, promote heart health, and help growing brains to develop. That organic milk is higher in omega-3s comes as little surprise, given that grass-fed beef is higher in omega-3 fatty acid than grain-fed beef. The Ellis study also found that organic cow milk has a lower omega-6:omega-3 fatty acid ratio than does conventional cow milk. American diets are notoriously high in omega-6 fatty acids, which are generally pro-inflammatory. A lower omega-6:omega-3 fatty acid ratio is an indicator of higher nutritional quality. Thus, though rBST doesn’t make a difference in milk quality, what the cows are eating most certainly does. The nutritional difference between conventional and organic milk is particularly important with regard to the whole milk (as opposed to skim) that is recommended for toddlers and young children.
Of course, organic milk (the USDA requirements for which preclude CAFO housing) is more expensive than conventional milk. Or at least, it appears that way. In reality, we pay more for conventional milk than we think we do, both in terms of the costs to the environment and in very literal monetary terms. CAFO farming is highly subsidized by the U.S. government, and taxpayer dollars go to supporting CAFOs. Grain subsidies for all CAFO livestock cost about $3.86 billion a year in taxpayer dollars (Starmer 2007), while cleaning up leakage from manure storage facilities (which barely mitigates the threat to the environment) is estimated to cost an additional $4.1 billion (Volland et al). It’s estimated that the direct public health costs associated with antibiotic overuse are around $1.5-3 billion a year (National Research Council, 1999 data), though this doesn’t include all the indirect costs, such as death and morbidity associated with antibiotic-resistant infection. CAFOs also affect the value of nearby properties by an estimated $26 billion in total loss (Mubarak et al). Conventional milk is cheap by the time it gets to the store, because taxpayers have already paid for it to the tune of billions of dollars a year.
Ultimately, the issue of organic versus conventional milk is one of consumer health. While a glass of organic skim milk may be quite similar to a glass of conventional skim milk, when it comes to 1%, 2%, or whole milk, organic is packed with healthier fats. Further, to buy conventional milk is to vote with one’s purchasing power for CAFO agriculture. To purchase conventional milk is to support continued government subsidies to CAFO operations, which drives the price of conventional milk down at the grocery store (but keeps the price high overall, because of all the tax dollars poured into the dairy industry). To purchase conventional milk is to vote for, among other things:
-Antibiotic resistant bacteria and an increase in drug-resistant infections
-Blue baby warnings and deaths
-Cows that eat other cows…and chicken poop
-Decreased property values
-Higher taxes due to farm subsidies
-Increased risk of mad cow disease
-Increased risk of painful mastitis in cows
Is all the conventional milk in the dairy aisle from CAFO cows? No, of course not. Joanna’s farm is an example of a non-CAFO, conventional farm with practices that sound quite ethical. If I could be sure that I was buying milk from a farm like Joanna’s, I’d be happy to serve it to my family. However, the vast majority of conventional milk in the dairy aisle does not come from farms like Joanna’s; it comes from CAFOs. For this reason, unless one is familiar with a particular conventional farm and its practices and purchases one’s milk expressly from that farm, conventional milk must be assumed to be CAFO milk, replete with its baggage.
The organic versus conventional debate is an insidious one. If conventional milk were significantly lower in nutrients than organic milk — or if there were data that showed it was high in harmful compounds — the vast majority of parents would stop buying it for their children. Providing for the health and welfare of our children is about more than just making sure the milk in the glass is nutritious, however; it is also about providing for our children’s (hopefully long) lives and livelihoods. It is about doing everything we can to avoid promoting antibiotic-resistant bacteria, so our children and grandchildren don’t succumb to a simple infection as humans so often did prior to the advent of antibiotics. It is about ensuring clean air for them to breathe, and clean water for them to drink. It is about setting an example of appropriate use of the land and the animals that live on it, so our children can follow in our footsteps. It is about maintaining our planet’s forests, oceans, and climate to the best of our abilities, and eschewing those practices that adversely impact them. It is about the big picture.
Author Bio: Kirstin Hendrickson is a science journalist and senior lecturer in the Department of Chemistry and Biochemistry at Arizona State University, where she focuses on sustainability and environmental issues. She has a PhD in Chemistry, and studies the reciprocal relationship between science and society and methods of communicating about science. She has written a textbook called Chemistry In The World, which focuses on the ways in which humans affect each other and the environment through chemistry. She blogs about evidence-based parenting and analyzes parenting-related research at www.SquintMom.com.
Chapin et al. Airborne multidrug-resistant bacteria isolated from a concentrated swine feeding operation. Environ Health Perspect. 2005 Feb;113(2):137-42.
Dohoo et al. A meta-analysis review of the effects of recombinant bovine somatotropin. 1. Methodology and effects on production. Can J Vet Res. 2003 Oct;67(4):241-51.
Dohoo et al. A meta-analysis review of the effects of recombinant bovine somatotropin. 2. Effects on animal health, reproductive performance, and culling. Can J Vet Res. 2003 Oct;67(4):252-64.
Eastridge et al. Major advances in applied dairy cattle nutrition. J Dairy Sci. 2006 Apr;89(4):1311-23.
Ellis et al. Comparing the fatty acid composition of organic and conventional milk. J Dairy Sci. 2006 Jun;89(6):1938-50.
Gibbs et al. Isolation of antibiotic-resistant bacteria from the air plume downwind of a swine confined or concentrated animal feeding operation. Environ Health Perspect. 2006 Jul;114(7):1032-7.
Imhoff, D., ed. CAFO: The Tragedy of Industrial Animal Factories. Earth Aware Editions, 2010.
Jenkins et al. Major advances in nutrition: impact on milk composition. J Dairy Sci. 2006 Apr;89(4):1302-10.
Koneswaran et al. Global farm animal production and global warming: impacting and mitigating climate change. Environ Health Perspect. 2008 May;116(5):578-82.
Langford et al. Antibiotic resistance in gut bacteria from dairy calves: a dose response to the level of antibiotics fed in milk. J Dairy Sci. 2003 Dec;86(12):3963-6.
Makovec et al. Antimicrobial resistance of bacteria isolated from dairy cow milk samples submitted for bacterial culture: 8,905 samples (1994-2001). J Am Vet Med Assoc. 2003 Jun 1;222(11):1582-9.
Mubarak, H., T.G. Johnson, and K.K. Miller. 1999. The impacts of animal feeding operations on rural land values. Report R-99-02. College of Agriculture, Food and Natural Resources, University of Missouri Columbia.
Mubarak, Johnson, and Miller 1999. Extrapolation from Mubarak, H., T.G. Johnson, and K.K. Miller. 1999. The impacts of animal feeding operations on rural land values. Report R-99-02. College of Agriculture, Food and Natural Resources, University of Missouri Columbia, based on national CAFO numbers.
National Research Council (NRC). 1999. The use of drugs in food animals: Benefits and risks. National Academies of Science. Washington, DC: National Academies Press. Extrapolation based on U.S. population of 300 million.
Pollan, M. The Omnivore’s Dilemma. Penguin, 2007.
Pruden et al. Antibiotic resistance genes as emerging contaminants: studies in northern Colorado. Environ Sci Technol. 2006 Dec 1;40(23):7445-50.
Raymond et al. Assessment and promotion of judicious antibiotic use on dairy farms in Washington State. J Dairy Sci. 2006 Aug;89(8):3228-40.
Sapkota et al. Antibiotic-resistant enterococci and fecal indicators in surface water and groundwater impacted by a concentrated swine feeding operation. Environ Health Perspect. 2007 Jul;115(7):1040-5.
Sapkota et al. What do we feed to food-production animals? A review of animal feed ingredients and their potential impacts on human health. Environ Health Perspect. 2007 May;115(5):663-70. Epub 2007 Feb 8.
Sawant et al. A survey on antibiotic usage in dairy herds in Pennsylvania. J Dairy Sci. 2005 Aug;88(8):2991-9.
Starmer, E. Personal communication with D. Gurian-Sherman of the Union of Concerned Scientists. 2007, see Gurian-Sherman, D. Cafos Uncovered. Union of Concerned Scientists, 2008.
Thames et al. Excretion of antibiotic resistance genes by dairy calves fed milk replacers with varying doses of antibiotics. Front Microbiol. 2012;3:139. Epub 2012 Apr 10.
VandeHaar et al. Major Advances in Nutrition: Relevance to the Sustainability of the Dairy Industry. J Dairy Sci. 2006 Apr;89(4):1280-91.
Volland et al. Cost of remediation of nitrogen-contaminated soils under CAFO impoundments. Journal of Hazardous Substance Research 2003; 4: 1–18.
Walczak et al. Manure as a Source of Antibiotic-Resistant Escherichia coli and Enterococci: a Case Study of a Wisconsin, USA Family Dairy Farm. Water, Air and Soil Pollution 2011; 219: 579-89.
Wells et al. Isolation of Escherichia coli serotype O157:H7 and other Shiga-like-toxin-producing E. coli from dairy cattle. J Clin Microbiol. 1991 May;29(5):985-9.