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Forage Particle Size

Dairyland provides Forage Particle Size analysis using the ASAE S424, which is the standard analysis that the Penn State Particle Separator is based upon (Lammers, 1996).  ASAE S424 was originally developed by researchers at the University of Wisconsin to evaluate the particle size of chopped forages.  This laboratory analysis features mechanical operatation, use of as-fed samples, and very large surface area, all of which enhance the repeatability and accuracy of the measured values (Mualfair et al., 2010).  Since its adoption by the American Society of Agriculture Engineers, this analysis has become the standard by which forage harvestor manufacturers measure particle length.

Dairyland Laboratories, Inc.
50 Corn Silage samples analyzed by ASAE S424 and the Penn State Particle Separator at Dairyland


The Forage Particle Size Report includes the following measurements:

Screen Number Length of particles on the screen Weight on screen (g) Percent of the total weight on screen Percent of weight on screens 1&2
1 >1.06 in. 88.5


2 >0.71 in. 88.6 5.83% 11.46%
3 >0.35 in. 551.3 36.27%  
4 >0.22 in. 397.7 26.17%  
5 >0.065 in. 255.4 16.88%  
PAN   141.4 9.30%  
MPL - Mean Particle Length = 0.29 Inches


The forage particle size seperator divides a sample into 6 particle size classes
The forage particle size separator divides a sample into 6 distinct particle size classes by shaking the sample through screens that vary in both width and depth of openings.


Researchers from the University of Wisconsin recommend the following for lactating dairy rations:

Forage Type Mean Particle Length (MPL) % of weight on screens 1&2
Individual Forage 0.375 15-20%
TMR Undefined 7-10%

Lammers, B.P., D.R. Buckmaster, and A. J. Heinrichs. 1996. A simple method for the analysis of particle sizes of forage and total mixed rations. J. Dairy Sci. 79:922-928.
Maulfair, D.D., G.I. Zanton, M.Fustini, and A.J. Heinrichs. 2010. Effect of feed sorting on chewing behavior, production, and rumen fermentation in lactating dairy cows. J. Dairy Sci. 93:4791-4803.


For more information call Dairyland Laboratories, Inc. at 608-323-2123 or contact us here.