SOURCES OF VARIANCE IN FEED DISTRIBUTION-SYSTEMS

Geometric mean diameter (GMD), by mass, and by protein, calcium and ph osphorus concentrations of mash poultry feed were measured throughout a state-of-the-art feed distribution system. Data was taken from the p ost-mixer mash to the point of consumption. The change in GMD of the f eed particles was determined for each of the four primary components o f the system: (1) post-mixer and mill tank; (2) transport bulk feed tr uck; (3) four on-farm storage bins; and (4) two in-house feed distribu tion systems. The protein, calcium and phosphorus concentrations were measured and the variances in GMD and nutrient contents were calculate d for the bins and the in-house distribution systems. The results defi ned the effects of various bin device configurations such as an electr ic hopper unloading aid (EHUA), a bin fill deflection device (BFDD), t he combination of both devices and no devices on particle size and nut rient variance. Inhouse distribution was via a drag auger or a drag ch ain. GMD was not significantly changed (p<0.05) by the post-mixer and mill tank, transport bulk feed truck, or the four on-farm storage bin treatments. However; GMD significantly decreased (p<0.05) as a result of the combination of the post-mixer and mill tank transport bulk feed truck and the on-farm storage; and as a result of the in-house distri bution systems. The bin devices had no significant (p<0.05) effects on GMD, GMD variance, nutrient variance, or day-to-day variances of the feed introduced to the in-house distribution system. Residual feed rem aining in the feeder troughs had significant effects (p<0.05) on the c hange in GMD and sample nutrient concentrations from the first samplin g location inside both production houses (prior to entering the drag a uger or drag chain) and the first (of five) sampling locations in each in-house distribution system. In addition, there were significant (p< 0.05) spatial differences only within the drag chain system; however t here were no significant (p<0.05) temporal differences between systems .