Methodological Correction Using Inert Materials Improves the Evaluation of the Aerobic Stability of Sudan Grass Silage

Aerobic stability is a key indicator of silage quality, reflecting microbial activity through increases in pH and temperature during exposure to oxygen. However, fluctuations in ambient temperature may compromise the accuracy of this assessment. This study evaluated the aerobic stability of Sudan grass silage subjected to different particle sizes (PS) and inoculation with homofermentative microorganisms, as well as the use of inert materials as thermal references. Twenty-four experimental PVC silos were used in a randomized block design with a 2 × 2 factorial arrangement, including two PS (small or large) and the presence or absence of a homofermentative inoculant (Lentilactobacillus plantarum and Pediococcus acidilactici). Additional silos containing inert materials (sand, water, sawdust, hay, expanded polystyrene, and air) were used to monitor environmental thermal variation. Smaller particles resulted in lower pH values throughout the aerobic exposure period, while larger particles showed higher pH and greater temperature increases, indicating lower stability. Microbial inoculation did not affect pH or temperature. Among the tested materials, sand most effectively buffered ambient temperature fluctuations, enabling more accurate detection of biologically driven heating. Thus, small particles enhance aerobic stability, and the use of sand as a thermal reference enhances the reliability of measurements under variable environmental conditions, offering a practical approach for silage evaluation outside controlled settings.