Home Pasture Health Raw Milk to Help Grass Grow?

Raw Milk to Help Grass Grow?


Thanks to Bridget Hilshey for this great piece.

By Stefan Kühn – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=23754

Sawing a person in half is magic. So is spraying a couple gallons of anything onto an acre of pasture and expecting production to double. When the lights come on or the sun comes up, the person is whole again and the pasture looks just like it did before you sprayed. Anyone who tells you anything else is either a conjurer or selling you something.

Spraying dilute raw milk onto pastures has recently gained attention as a potential means of increasing forage production and quality.  All dairy operations generate milk and whey that is not saleable, usually around 5.75 to 16 gallons per cow per year. For farmers, it can represent a large economic loss to the farm and a confounding disposal problem. Disposal through waste-water treatment plants impair the plant’s functioning.  Effluent storage ponds don’t fair any better.  With biological oxygen demands of more than 10 times that of raw sewage, milk and whey discharged into storage ponds can overwhelm the processing bacteria.  The result is inefficient and very stinky anaerobic decomposition.  The easiest, least expensive and most environmentally friendly means of disposing of large quantities of milk has always been to feed it to other livestock or land application.  In fact, disposing of milk by spreading it is a recommended means of dealing with it.

But how did we get from simple, safe disposal to applying milk as  soil amendment?  Raw milk is not something you’d pick up at Agway, so even though it has no sales force behind it, maybe there is a reason some people promote it as a way to improve pastures. Milk contains proteins and other compounds which are potent fungicides and viricides. There are amino acids in milk and maybe they  stimulate grass growth and vigor. There is a wide variety of bacteria naturally occurring in milk; those night be beneficial soil microbes.  But do all these factors add anything to your bottom line?

The short answer is: no, we don’t think so.

Graziers expressed interest in learning more about this practice to help them decide whether it was worthwhile to adopt this practice.  So researchers complied, setting up the first and only known controlled and replicated on-farm analysis of the effects of raw milk on pasture.  The study was completed this year under a SARE Partnership Grant.  Two Vermont dairy farmers, John Clark, of Applecheek Family Farm, and Guy Choiniere, of Choiniere Dairy Farm, sprayed 20 gallons of raw milk per acre on 2-3 acres of mature pasture in the spring of 2012. Then, one and two months later, University of Vermont graduate students analyzed almost 200 forage and soil samples from those pastures and from adjacent pastures not getting raw milk. Extremely dry weather that summer could have muted any effects of raw milk, but there were no differences between the plots, and the farmers couldn’t tell where they had sprayed either. There probably wasn’t any difference because the raw milk simply doesn’t do anything.

It would be nice to think raw milk is a great pasture rejuvenator, but  so far, it hasn’t shown any signs of being one. Unless and until other research proves otherwise, we say spraying raw milk is simply a way to get rid of excess milk. If you have data or documentation to prove otherwise, please share it with us. We’ll be sharing more stories on this topic in issues to come.


  1. Has anyone questioned if the fat/cream in the milk effects results? The above article mentions raw milk. I’ve read in another report that a dairy farmer sprayed skimmed milk on his field because the cream was removed and used for butter. Just wondering if the cream in the milk would actually cancel out any good the milk would do for the biology of the soil.

  2. I may be crazy, but the idea that you can apply milk to pasture, wait 2 months and then test it seems like a poor study. It takes time to amend soils and for beneficial microbes to flourish. I’m no scientist, nor an expert on grazing. However, I do know that it can take months and years to see results from a natural soil amendment. Quite frankly I’ve seen chemicals that state you must apply numerous times for maximum effectiveness. It appears to me the study was a bit skewed toward the good of big-business. For those of us who aren’t interested in promoting big-business and using chemical means of improving our ground (which is an oxymoron in my opinion), we are willing to take the TIME (which this so-called study obviously did not) to deliberate and see how soil is improved over years and repeated applications. It’s a shame no studies were done on the soils where dairies sprayed their pastures with raw milk. That would have given a much more accurate picture on what was going on with the soil health.

    It is also important to add that few people have access to large quantities of raw milk. Thanks to most state laws making raw milk illegal to sell, and the majority of people not having the space, knowledge and know-how to raise a family milk cow and have enough left over to put on pasture, many individuals are without the ability to test this theory themselves. Many of us who do have access are testing this theory.

    What I find truly disturbing about this article is that there seems to be little emphasis on soil improvement and more about improving the bottom line and doing so immediately. The long term benefits aren’t brought up at all. I suppose that makes sense considering the test was only 2 months long. The bottom line is important to all farmers, but it’s not always the first item on the list.

    • Hello Kristi,

      We agree 100% with you that soil amendments take time to flourish. But not everyone knows that. In this case Ms. Hilshey’s study was created in part to address claims made that such rapid improvements do occur by spraying raw milk on pasture. These claims arose in part because of a one year study done in Nebraska at a dairy farm using raw milk. As I noted in my reply to Chuck’s comment, I have seen the data from the Nebraska study, and what they tell us is that there was no statistical difference between the control pastures and the treatment pastures. Unfortunately the results of the short trial were misinterpreted and the idea that huge increases in forage could result from raw milk application was widely distributed. Some farmers tried the practice, others asked for more information. Thus, we felt it was important to share the results of Ms. Hilshey’s study.

      Dairies have struggled with what to do with excess or unusable milk and disposing of it by spreading it on pasture is an approved and common practice. This may have led to the thought that there might be beneficial effects from the application of raw milk. As noted in the article, Ms. Hilshey’s study was conducted on dairy farms, and their waste raw milk was used for the trial so that as you said, they could get a more accurate picture of what was going on. The results are just one of the bricks that we can all use to build a better understanding and additional research will of course give us more knowledge. We continue to invite anyone with data on the benefits of raw milk as a soil amendment to share them.

      I’ve re-read the article numerous times since receiving your comment, trying to find how you inferred that it promoted “big-business and using chemical means of improving our ground” or that there was “little emphasis on soil improvement and more about improving the bottom line…immediately.” Having contributed to the article’s development, I know that our goal was simply to let readers know that the immediate results they may have been led to expect from raw milk spraying are wishful thinking at best. What to do to achieve success wasn’t within the scope of this article and would require a lot more than the article’s 570 or so words.

      It is one of our goals to provide information that helps readers understand their soils so that they can make educated decisions about how best to spend their time and money to improve them. To that end we have begun a series of articles that you can find here. We hope they clarify our thoughts on soil and its management and improvement.

  3. Howdy,
    I posted on FB also but I’m wondering if you have a link to this study? If the fields were in good condition biologically then there will likely be little difference. Raw milk can be viewed as a “jump starter” for degenerated soils with poor biological communities.
    Very few things (inputs) will be of any value to an already healthy soil system.
    I would really like to see the details of the study.

    • Hello Chuck,

      The data from this masters thesis will be defended mid-May, and all data will be available after that, so we can share more. In the meantime, we’d love to see data that you have that supports raw milk as a “jump starter.” I am also working with the people in Nebraska to release the data that they have that was the foundation for claims of 2 gallons of milk per acre causing large increases in forage quantity and quality. I’ve seen the data and, unfortunately, it doesn’t support that conclusion.

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