Mixing and clean-out properties of sulfamethazine and carbadox in swine feed (1995)

Abstract

Two forms of sulfamethazine (pelleted and granular) and one form of carbadox (granular) were evaluated for their mixing and clean-out properties in replicated batches of swine feed prepared at the research feed mill at Kansas State University. Analysis of variance indicated that carbadox was incorporated into the feed more uniformly than sulfamethazine. Additional mixing beyond 1.5 minutes did not improve drug distribution (P>0.05). A paired-comparison T-test was used to compare mixing properties of drugs versus salt (the latter is commonly used to test mixer performance). We found the mixing properties of sulfamethazine and salt to be different (P 0.05). Ground corn was used to flush the mixer and conveying system between feed batches; then the mixer, leg, and sack-off bin were cleaned, and materials were assayed for drug carryover. Sulfamethazine was detected in the mixer cleanout material at concentrations of 12.6 ppm and 8.1 ppm for the granular and pellet forms, respectively. Carbadox carryover was not detected in mixer clean-out material. Detectable concentrations for all three drugs occurred in cleanout material from the leg and sack-off bin.