SOURCES OF VARIANCE IN FEED DISTRIBUTION SYSTEMS

Abstract

Geometric mean diameter (GMD), by mass, and by protein, calcium and phosphorus concentrations of mashpoultry feed were measured throughout a state-of-the-art feed distribution system. Data was taken from the post-mixermash to the point of consumption. The change in GMD of the feed particles was determined for each of the four primarycomponents of the system: (1) post-mixer and mill tank; (2) transport bulk feed truck; (3) four on-farm storage bins; and(4) two in-house feed distribution systems. The protein, calcium and phosphorus concentrations were measured and thevariances in GMD and nutrient contents were calculated for the bins and the in-house distribution systems. The resultsdefined the effects of various bin device configurations such as an electric hopper unloading aid (EHUA), a bin filldeflection device (BFDD), the combination of both devices and no devices on particle size and nutrient variance. Inhousedistribution was via a drag auger or a drag chain.<br><br>GMD was not significantly changed (p<0.05) by the post-mixer and mill tank, transport bulk feed truck, or the four onfarmstorage bin treatments. However, GMD significantly decreased (p<0.05) as a result of the combination of the postmixerand mill tank, transport bulk feed truck and the on-farm storage; and as a result of the in-house distributionsystems. The bin devices had no significant (p<0.05) effects on GMD, GMD variance, nutrient variance, or day-to-dayvariances of the feed introduced to the in-house distribution system.<br><br>Residual feed remaining in the feeder troughs had significant effects (p<0.05) on the change in GMD and samplenutrient concentrations from the first sampling location inside both production houses (prior to entering the drag augeror drag chain) and the first (of five) sampling locations in each in-house distribution system. In addition, there weresignificant (p<0.05) spatial differences only within the drag chain system; however, there were no significant (p<0.05)temporal differences between systems.