Before we get into why grass-fed dairy is so important, we might wonder what exactly is grass-fed dairy?
Grass-fed dairy is exactly what it says it is, milk sourced from cows that have grazed in pasture or grass or dried forages (such as hay) during their life. This means their diet consists of 0% processed foods - no grains, no corn, and no soy.
So, what difference does a cow's diet make?
THE COW
The difference starts with the cow's life! A cow's digestive system is designed to digest pasture. A grain-based diet can actually harm a cow's health and the safety of its milk for humans. A cow's health is enhanced when it can feed on nutritionally rich mixtures of grasses, shrubs, and trees. Thus, these animals need less antibiotics. Meanwhile, the overuse of antibiotics in conventional feedlots contributes to the global health concern of antibiotic resistance.
THE HUMAN
The difference can also be noticed in the quality of the milk! Grass-feeding can improve the quality of cow's milk in several ways.
Let's begin with the better ratio of omega-6 to omega-3 fatty acids in grass-fed cow's milk. A healthy diet ideally consists of 1-4 times more omega-6 fatty acids than omega-3 fatty acids. Unfortunately, the standard American diet provides 11-30 times more omega-6 than omega-3. This ratio is out of control! This ratio has been suggested as one of the reasons there are so many inflammatory disorders in the US. The reason we need the ratio to be just right (no greater than about 4:1) is because excess of one family of fatty acids (omega-6 or omega-3) can interfere with the proper metabolism of the other family.
So how does milk from grass-fed cows compare to grain-fed cows when it comes to the omega-6 to omega-3 ratio? One study found the ratio 0.95 for grass-fed milk (remember, the smaller the ratio, the better) and 5.77 for conventional milk.
We know dairy intake is so high in the US. Meanwhile, most households find it challenging to consume omega-3 rich fish on a regular basis to get all the omega-3 they need from their diet. Grass-fed cow's milk may help in that sense.
As a plus, grass-fed cows produce milk with almost four times more beta-carotene than milk of conventionally fed cows, more vitamin E, and more conjugated linoleic acid (CLA). CLA is an essential omega-6 fatty acid that actually has anti-inflammatory properties.
On the flipside, conventionally fed cows tend to produce milk with higher concentrations of cholesterol-raising saturated fats. Several studies suggest that a grass-based diet also increases the concentration of cancer-fighting antioxidants, such as glutathione and superoxide dismutase compared to grain-fed cows milk.
THE ENVIRONMENT
Finally, the difference can impact the environment. When cows graze, their nitrogen-rich manure contributes to better soil quality. Better soil means better quality grass for the cows to feed on.
One study found that grass-feeding results in les production of methane emissions per cow.
Interestingly, one study mentioned that of the 80 top ways to reduce climate change, grazing (as a part of regenerative agriculture) ranks as a number one way to reduce greenhouse gas emissions.
If either of these things - health (especially metabolic and cardiovascular health), animal welfare, or environmental health - are important to you, grass-fed dairy may be a good option.
Thankfully, the number of options out there for grass-fed dairy products is growing. Butter, yogurt, and cheese products can also be found that are made with grass-fed milk. Finally, if you're looking to stick to grass-fed dairy, you may want to make sure that even your whey protein powder is made from grass-fed cow's milk, such as ProEnergy Whey Protein Isolate from EnergyFirst.
References
Alothman, M., Hogan, S. A., Hennessy, D., Dillon, P., Kilcawley, K. N., O'Donovan, M., Tobin, J., Fenelon, M. A., & O'Callaghan, T. F. (2019). The "Grass-Fed" Milk Story: Understanding the Impact of Pasture Feeding on the Composition and Quality of Bovine Milk. Foods (Basel, Switzerland), 8(8), 350. https://doi.org/10.339/foods8080350
Benbrook, C. M., Davis, D. R., Heins, B. J., Latif, M. A., Leifert, C., Peterman, L., Butler, G., Faergeman, O., Abel-Caines, S., & Baranski, M. (2018). Enhancing the fatty acid profile of milk through forage-based rations, with nutrition modeling of diet outcomes. Food science & nutrition, 6(3), 681–700. https://doi.org/10.1002/fsn3.610
Elgersma A, Ellen G, van der Horst H et al. Quick changes in milk fat composition from cows after transition from fresh grass to a silage diet. Animal Feed Science and Technology, Vol 117, Issues 1-2, 10 Nov 2004, 13-27.
Couvreur S, Hurtaud C, Lopez C et al. The Linear Relationship Between the Proportion of Fresh Grass in the Cow Diet, Milk Fatty Acid Composition, and Butter Properties. Journal of Dairy Science, Vol 89, Issue 6, June 2006, 1956-1969.
Hebeisen, D. F., Hoeflin, F., Reusch, H. P., Junker, E., & Lauterburg, B. H. (1993). Increased concentrations of omega-3 fatty acids in milk and platelet rich plasma of grass-fed cows. International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition, 63(3), 229–233.
Dhiman, T. R., Anand, G. R., Satter, L. D., & Pariza, M. W. (1999). Conjugated linoleic acid content of milk from cows fed different diets. Journal of dairy science, 82(10), 2146–2156. https://doi.org/10.3168/jds.S0022-0302(99)75458-5
Hawken P. Drawdown: The Most Comprehensive Plan Ever Proposed to Reverse Global Warming. New York, NY: Penguin Books; (2017)
Provenza, F. D., Kronberg, S. L., & Gregorini, P. (2019). Is Grassfed Meat and Dairy Better for Human and Environmental Health?. Frontiers in nutrition, 6, 26. https://doi.org/10.3389/fnut.2019.00026