Nutritional and Economic Implications of Protein Variance and Application of Statistical Process Control in the Chinese Feed Industry
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The adoption of Statistical Process Control (SPC) in the Chinese feed industry to reduce finished feed protein and moisture content variation can improve feed quality and profitability. Two studies were conducted to characterize protein variation in the Chinese feed industry. Study I involved four participating feed mills where we collected three samples per bag from four bags per lot of soybean meal, rapeseed meal, fish meal, corn gluten meal, meat & bone meal, and cottonseed meal. We analyzed these ingredients for protein and moisture content. Cottonseed meal and meat & bone meal displayed the highest protein variability between bags and within bags compared with other protein ingredients. We found no significant difference for within-bag protein variance of the other feed ingredients; however, soybean meal had a significantly lower between-bag variance (0.04%). Study II assessed the effect of adopting SPC. Five feed mills provided data for one year of finished feed protein and moisture content before and after adopting SPC. Three of the five feed mills experienced a significant (P < 0.10) reduction (0.20, 0.52, and 0.70%) in the absolute finished feed protein variation after adopting SPC. The two feed mills that did not display a significant reduction in absolute protein variation were already manufacturing feed with a low (<0.4% protein) absolute deviation from the target. These data demonstrate that feed mill managers can control finished feed variability through a number of management techniques including SPC.