The effect of a dacitic tuff breccia (Azomite) in corn, soybean, and dried distillers grains with solubles–based diets that vary in inorganic phosphate source on pellet mill production rate and pellet quality

Summary: Feed mill pellet production rate is of great importance to integrated meat bird production. Ingredients such as dried distillers grains with solubles (DDGS), inorganic phosphate source (IPS), and fat influence production rate and feed quality because of their composition. The naturally abrasive properties of an IPS may scour the pellet die and affect the feed production rate. The objective of the study was to evaluate the effect of a dacitic tuff breccia (Azomite [AZM]) inclusion in a corn, soybean meal, and DDGS–based diet with either dicalcium phosphate (DCP) or tricalcium phosphate (TCP) on pellet mill production rate, hot pellet temperature, and pellet quality. The assessment included 4 experimental treatments in a 2 (DCP or TCP) x 2 (AZM or no AZM) factorial latin square design across 4 manufacturing d with complete blocks in each d. Average temperature and humidity were 16°C and 67%, respectively. There was a 6 percent increase in production rate when AZM was added to DCP diets (0.99 vs. 1.05 MT/h; P < 0.001) and an 8 percent increase in production rate when AZM was added to TCP diets (1.10 vs. 1.19 MT/h; P < 0.001). The increased production rate that favored AZM and TCP diets may be associated with an additive effect of pellet die scouring. Inorganic phosphate source and AZM interacted to affect pellet quality (P < 0.021) demonstrating that increased production rate decreased pellet quality; however, the greatest amount of the observed change (3 percent) would likely have little effect on bird performance. This study was successfully designed to remove confounding treatment effects of the d of manufacture and run order.