The Penn State particle separator, commonly called “the shaker box,” is a very useful tool for conducting nutritional analysis on dairy farms. The particle separator is a “square box” made up of two or three sieves having different sized holes at each level superimposed on a bottom pan.
Shaker box testing provides a simple way to evaluate particle size of wet forages and total mixed rations (TMR). A sample of 400 grams of feed is placed in the top sieve and the separator is shaken according to the user’s manual.
Feed particles retained on each level are then weighed. The proportion of feed particles retained on the top two sieves is considered a good estimate of the proportion of physically effective particles that are long enough to cause rumination in the cow.
Source: January 2009 issue of MilkPRODUCER magazine published monthly by Dairy Farmers of Ontario. Page 30