Slurry & Manure
72-cow dairy on straw and shavings: a 24-inch slurry crust gone by spring, with very little agitation.
Newswenger dairy, 72 cows · Shelby, Ohio, USA · 22 October 2026
The challenge
Merlin Newswenger kept 72 cows bedded on straw and shavings. The lagoon had to be emptied about every four months, and the crust had grown so thick that the manure hauler charged extra to agitate it before every pump-out. Merlin also had to watch and move the agitation equipment several times over two hours each time.
The approach
In late December 2004 the liquid was taken out from under two feet of frozen crust and 6 gallons of MICROBE-LIFT®/DFP were added. One gallon a week followed for four weeks, then one gallon a month for February, March and April.
Results
24 in → gone
Surface crust at clean-out
Very little
Agitation needed
Even, top to bottom
Slurry
6 gal, then 1 a week, then 1 a month
Programme
At clean-out in early May the whole 24 inches of crust had gone, leaving only a thin scum that took very little agitation to mix in. Farmer and hauler both said the lagoon was consistent from top to bottom, and the slurry spread evenly without the usual chunks. The farm is remote, so odour was not recorded. Ecological Laboratories present this as a field report from one farm: results depend on the store, the bedding and the dosing, which is why we size every programme to the tank in front of us.
Source documentation
Ecological Laboratories case studies (opens in a new tab)