West-Central Forage Association

Milk Application on Pasture


Farmer talk has suggested that application of waste milk to fields (either as a byproduct of skimming fat for cheese or cream) shows better grass growth and palatability for cows.  Results have been seen in the first year, but may diminish over the years as the soil gets healthier and heals.  In the US it is thought that anywhere from 500 - 1000 farmers are using this practice.  When the price of milk is low, some farmers find it more cost effective to use it as a soil enhancer.

Noted benefits

  • Better quality grass (higher nutrient content) and higher yields
  • Softer soil with higher porosity (better ability to absorb water and air)
  • Better penetration in the winter
  • Cows seemed to choose the patches of grass that had milk applied to them.
  • Causes grasshoppers to disappear - milk has high sugar content and since grasshoppers do not have a pancreas they cannot process the sugar.   
  • Sodium levels in the soils are reduced - may reflect damage from chemicals that is cleaned up by the microbes or enzymes. 

Why milk might works: Milk is high in protein and sugars that the soil microbes need for growth.   Raw milk has one of the most complete amino acid structures known in a food (proteins).  It also has a really good sugar complex.   It is an excellent source of vitamin B can works with enzymes to break down food for microbes and plants (tillage, sprays, chemicals, overgrazing can kill microbes)

The top 6" of soil has x lb's of bacteria per acre - let's call it 4000 lb's per acre.  Bacteria need perfect food for growth and health.  Raw milk is this source as it contains Vitamin B's, enzymes, protein structure, sugar etc... Under perfect conditions bacteria will double every 15 minutes.  Bacteria are 90% protein (worms need protein to thrive), and give off 14% of weight in nitrogen, 3% phosphorus and 1% potassium.  It does not take much growth to put out 140 lb's of nitrogen through growing bacteria.  The healthier the soils the easier it is to make a difference when doubling the counts.  Also watch for fungicide action and insecticide action.


The Dairy Industry Act does not restrict a dairy producer from spreading milk onto their fields / pastures.  This is often done when a load is rejected at the farm and the producer must dispose of it from the bulk milk tank.  The Dairy Industry Act does prohibit the sale of this milk so a dairy producer could only use it for application on their own land. They could not supply it to neighbors, friends etc. for application onto their land.  Natural Resource Conservation Board (NRCB) who administers the Agriculture Operations Practices Act (AOPA) stated they advise their legislation does not prohibit this type of application as their legislation deals only with the application of manure.  A review of the Environmental Protection and Enhancement Act which is administered by Alberta Environment and this legislation would not prohibit this type of activity.  To ensure their legislation does not contain any sections that may prohibit this practice it is suggested to call the closest office location.

Keith McAllister, Manager Inspection and Investigation Branch with the Government of Alberta.  Keith.McAllister@gov.ab.ca


Application rates

For the purpose of this trial four applications rates have been chosen:

.5, 1.5, 2.5 and 5 gallons per acre with moist soils above 55°F (12°C) with application 30 days apart for four applications.  Forage quality and yield will be assesed annually

Over years you might find diminishing returns...as your soils heal and become healthy again.  Mastitis milk should not be used (or any milk from cows treated with antibiotics).  Ideally, it would be milk out of the bulk tank, but fresh cow milk (without antibiotic residue, i.e. ~ 60 days dry period) might work. 

Soil sampling

  • Biology to be done with Soil Food Web Canada
  • Late October is too late to do biology on the soil as they are no longer really active.  It is best to wait until the spring after the soil has reached about 10°C for about 2 weeks (and before application!) then follow up in late September.  Once the soil is below 8-10°C bacteria activity is cut by about 75%.
  • Fungi and protozoa should be done in the fall.  They are not active in the spring; rather, they feed on bacteria and increase in numbers in the summer and fall (starting about July)
  • Basic chemistry

There are no results on this project as 2012 was the first year. Spraying was conducted from July to August but no comparative information is available until soil samples are taken in the spring of 2013.