Raw waste milk as a pasture amendment

2013 Annual Report for ONE12-155

Project Type: Partnership
Funds awarded in 2012: $14,944.00
Projected End Date: 12/31/2014
Region: Northeast
State: Vermont
Project Leader:
Dr. Sid Bosworth
University of Vermont

Raw waste milk as a pasture amendment


Spaying dilute raw milk onto pastures is a novel, untested practice that has recently gained widespread prominence as a potential means of increasing forage production and quality. This partnership project investigated if foliar applications of dilute raw milk on pasture would improve the productivity, palatability and quality of pasture using an on-farm testing method on two organic dairy farms.   In 2012, two Vermont organic dairy farms, Choiniere Family Farm and Applecheck Family Farm, partnered with University of Vermont researchers to examine the impact of raw milk on pasture yield, forage quality and soil fertility. Each of the farms followed a similar research protocol. Dilute raw milk (2X) applied at a rate of 20 gallons active ingredient per acre was compared to a non-treated control, replicated in six paddocks on each farm. We found no significant difference in forage quality, soil quality, and forage production between areas sprayed with milk and non-treated control areas.  In a concurrent greenhouse study using perennial ryegrass seedlings, the only growth parameter that showed a significant increase to raw milk was tillering rate during the initial growth but no in the subsequent regrowth. To follow up on the 2012 year, a replicated field trial comparing raw milk applied at two rates, 5 and 10 gallons/acre, was conducted at the Larson Farm in Wells, VT. As in 2012, we found no difference in pre or post grazing yield during the subsequent grazing period. It may be that there are too many environmental variables in the field for the slight benefits we found in the controlled environment of the greenhouse to be expressed and be biologically or economically significant.

Objectives/Performance Targets

Objective 1: Assess changes in pasture soil health, and forage production, quality, and palatability that occur as a result of a dilute foliar application of waste (or raw) milk.

       As a follow up to the 2012 year, a replicated field trial was implemented at the Larson farm in Wells, VT in July of 2013. The field was an existing pasture consisting of mixed grasses predominately tall fescue. A soil test of the study area showed that all major nutrients were adequate and the soil pH was 7.1. There were four treatments with six replications, a control, raw milk applied at 5 and 10 gallons/a, and diluted whey applied at approximately 40 gallons/acre. Plots were 12 by 25 feet each. Pre and post grazing mass was measured during the subsequent grazing using a calibrated rising plate meter. Samples were also collected for forage analysis.

Objective 2: Provide graziers with a prototype On-Farm Testing (OFT) methodology that can be replicated on other farms in order to test other products and practices.

A draft manual was developed in January and used in a session at the Vermont Grazing and Livestock Conference. The final product will be produced in January 2014.


January 2013

Findings regarding raw milk application were presented at Vermont Grazing and Livestock conference. Accomplished. Bridgett Jamison Hilshey, graduate student and project assistant, gave a 30 minute presentation on the study to approximately 30 farmers.

February 2013

Present findings regarding raw milk application at Northeast Pasture Consortium Annual Meeting Accomplished. The results were presented during a poster session at the NE Pasture Consortium meeting by Sid Bosworth. The title of the poster was, “Raw Waste Milk as a Pasture Amendment” Approximately 60 attended the consortium with most of them viewing the poster.

February – April 2013

Prepare and submit experimental data for publication in a peer reviewed journal (Bosworth and Graduate Student). Bridgett Jamison Hilshey completed the data evaluation and interpretation of the 2012 studies and as a result completed her M.S. Thesis, which is published at the University of Vermont Library. She is currently working on two papers for peer review publication. One will be a methods paper entitled, “Simple, low cost method of separating living and dead pasture plant tissue using image spectroscopy”. It describes a new method of determining the amount of dead forage in a sample using digital image analysis. The method was developed in conjunction with the field research. A draft of the paper is attached. The second paper describes the effects of milk on pasture using both the field and greenhouse studies.   It is currently in the works and will be completed by the summer of 2013.

May 2013

Identified a new farm site at the Larson Farm in Wells, VT to conduct another field trial.

July 2013

The study was implanted July 17 at the Larson Farm. The study was highlighted during a field meeting held at the farm on July 24. Results from the previous year were discussed. No results were yet measured at the Larson farm.

August 2013

Pre and post grazing mass measurements were collected at the Larson study. Samples were collected for forage analysis.

Dec 2013

Analyzed results of Larson trial.

Impacts and Contributions/Outcomes

Even though an application of raw milk had a positive effect on initial grass tiller production and yield in the greenhouse study, we found no effect of milk on pasture growth or yield within the first 60 days of application in three different on-farm trials. There are several possible explanations.   First, the dry conditions present during the summer of 2012 may have inhibited any stimulatory effect milk might otherwise have had. During the summer of 2012, the experimental sites received less than 3.5 centimeters of rain. As a result, very little of milk sprayed onto plant leaves was likely not washed into the soil via a natural precipitation event. In addition, under the doughty summer conditions soil microbial activity and nutrient cycling would process slowly. The dry conditions may have inhibited the movement of the beneficial bacterial into the soil thereby negating the potential for milk to positively influence soil and forage parameters. The other condition that may make this difficult for dairy grazers is the level of residue at time of application. In all three farm studies, the pasture residue at time of treatment was at least at four inches. This could have interfered with any milk getting to the soil while still biologically active. Or, it may also be that there are too many environmental variables in the field for the slight benefits we found in the controlled environment of the greenhouse to be expressed and be biologically or economically significant.

The results of this experiment indicate that the application of raw milk onto pasture is not an economical means enhancing forage production or forage and soil quality. The meager gains recorded are neither great enough to influence milk production nor consistent enough to be a reliable solution.  

Results of this project were presented at the following events:

  • Initial results were presented at a University of Vermont Plant and Soil Science Seminar in 2012 (approximately 20 attendees).
  • A brief article outlining the study was also submitted to The Solar Dollar, the Vermont Grass Farmer’s Association Newsletter in 2012.
  • A presentation on the raw milk studies was given at the Vermont Grazing and Livestock Conference at Lake Morey Inn in January 2013 (30 farmers)
  • A presentation on conducting on-farm pasture research was made at the same Vermont Grazing and Livestock Conference (15 attended)
  • A poster presentation was given at the Northeast Pasture Consortium in Manchester, NH in Feb. 2013
  • An article was published in On Pasture in April 2013 (http://www.nodpa.com/research_ed_milk_as_biostimulant_060313.shtml)
  • An article was published in the Northeast Organic Dairy Producers Alliance News in June 2013 (http://www.nodpa.com/research_ed_milk_as_biostimulant_060313.shtml)



Bridgett Jamison

Graduate Student
University of Vermont
Plant and Soil Science Dept. Jeffords Hall
63 Carrigan Drive
Burlington, VT 05405-0082