A New Protocol for Homogeneity Testing in Feed Mill Concentrate Rations

To ensure an accurate homogeneity test, animal feed manufacturers should apply standardised techniques and procedures, which aim to guarantee the product quality. Our objective was to propose a new protocol for performing concentrate ration homogeneity tests in commercial feed mills, based on three main points: the suitability of different minerals as markers; establishing a simplified and reliable sampling protocol; and developing a simplified statistical approach for evaluating marker dispersion among increments. Four horizontal commercially available mixers were used. Increments were collected sequentially during the mixer-emptying time over five consecutive days, totalling 200 increments, in which nine potential mineral markers were evaluated. The minerals potassium (K) and magnesium (Mg) were considered suitable, as they simultaneously exhibited low variability among batches, among mixers, and among increments. Based on the variation patterns of K and Mg, the new protocol for homogeneity testing in feed mill concentrate rations is based on the following additional key points: two increments must be collected per ration batch, taken during the mixer-emptying operation—specifically at the second and eight tenths of the mixer-emptying time, and a concentrate ration mixture is considered homogeneous when the ratio between the highest and lowest marker contents in the increments is lower than 1.26.