With these advantages also come the challenges of handling sand-laden manure. If handled as a liquid, the sand tends to settle out of suspension. It is very abrasive and hard on equipment. Ideal bedding sand contains no stones, no organic matter, negligible clay, and has a loose, porous structure. Sand having a large particle size settles out quickly and is difficult to put back into suspension in manure storage units.
Coarse sand is also the most abrasive to manure handling equipment.
Fine-textured sand tends to pack and is less porous. Also small particles of sand are easily tracked by the cows into the milking parlor and they can enter sealed components in equipment. Since sand has a density of 100 lbs per cubic foot, it adds considerable weight to the manure mixture. A gallon of raw manure with organic bedding weighs about eight lbs, while sand-laden manure weighs ten lbs or more. Two problems associated with handling sand-laden manure are rapid rate of wear on pumping equipment and the agitation required to get the sand into suspension.