“Shake It” like a Penn State Particle Separator Test

9-7 penn state

Total Mixed Rations (TMR) – How do you ensure you have a truly balanced ration? Measuring is the best way to know. The Penn State Particle Separator (PSPS) test takes 5 minutes to do and can save you months of headaches. Particle size distribution is imperative in preventing sorting and also ensuring cows are getting proper feed that will encourage rumen production and provide necessary nutrients.

When feeding a TMR, it is important not only to have a balanced ration, but to have a variety of particle lengths to aid in rumen function. The longer particles help to initiate rumen activity, which allows cows to chew cud, producing saliva to assist in fermentation. However, if particles are too long, the cows will sort through the feed and not eat them, meaning they don’t get the proper nutrition.

To perform a PSPS, stack the 4 plastic separator boxes on top of each other, with the largest holes on top, going down to the smallest on the bottom.  Take handfuls of feed from different parts of the feed line and place into the top sieve of the stack. Using a flat surface, shake 5 times in one direction, then rotate a quarter turn and repeat this process for a total of 8 sets (40 shakes). No vertical motion should occur during this time. Shake hard enough that particles are able to slide over surface and fall through to other levels below. Once done, weigh each sieve individually to see the weights of various particle sizes. Use the weights to get a ratio for each box (length) and compare to PSPS charts to see how your TMR stacks up.

For step-by-step instructions with pictures and charts, check out our previous blog post here.


“Penn State Particle Separator.” Penn State University

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