Comparison of In Vitro Fermentation Characteristics Among Five Maize Varieties

Maize (Zea mays L.) silage in the irrigated and flat areas of Italy represents the most important large ruminant feed crop due to the high dry matter yield and nutritive value per hectare. The aim of the investigation was to evaluate the chemical composition and the in vitro fermentation patterns of five maize varieties (Tiesto, R700 1, MAS 78.T, DKC 7074 and KWS Kantico) freshly chopped and preserved via ensiling. The results indicated that the chemical composition was not significantly different among varieties. The substrates were incubated for 72 h with buffered rumen fluid collected from cow. The ensiling process slightly reduced gas production and fermentation kinetics, likely due to the consumption of soluble sugars during fermentation. Organic matter loss (OM loss) differed significantly (p < 0.01) among varieties in ensiled maize, correlating with their neutral detergent fiber (NDF) content. While total volatile fatty acid (VFA) production showed no significant differences between varieties, the buffer capacity ratio (BCR), an indicator of protein degradation, varied significantly. Ammonia production (NH3) was significantly higher in ensiled samples, supporting previous findings that ensiling increases non-protein nitrogen (NPN) due to microbial proteolysis and plant enzyme activity. The gas production profiles and fermentation rates over time showed minor differences between fresh and ensiled samples, with fresh material exhibiting faster fermentation kinetics due to the presence of soluble sugars. These findings highlight the importance of evaluating maize silage quality to optimize ruminant nutrition and feed efficiency.