Effect of the Addition of Enzymes on Chemical Composition and In Vitro Gas Production of Hybrid Maize Varieties Preserved by Silage in the Highlands

The aim of this study was to evaluate the chemical composition and in vitro gas production of ten varieties of corn hybrids (Owl, Copper, Chrome, H40, H47, H66, H70, HIT7, Pioneer 1832 and Victoria) cropped in the high valleys of Mexico, preserved by ensiling with three treatments, control (CTR), acetic acid 1% (AAC), or enzymes (ENZ, Sill all ® 10g/ton); samples were performed in microsilos (n=90); After 60 days, the micro-silages were opened. The data matrix was analysed using two multivariate techniques: (i) the variables considered for the Principal Components Factor Analysis (PCFA), and (ii) Hierarchical Cluster Analysis (CA). The first multivariate technique was to reduce the information and generate major factors. Cluster analysis shows the presence of four groups with different characteristics between the groups: G1 as energy silages (H47 and Pioneer varieties), G2 protein silages (Chrome, H66, Victoria varieties), G3 easily degradable silages (Copper, HIT7 varieties), and G4 balanced silage (Owl, H40, H70 varieties). Treatments AAC and ENZ in G2, and ENZ in G3 were higher in crude protein (CP) content than the rest of the treatments. Treatments with ENZ in G1, G2, and G3 had the highest neutral detergent fiber (NDF) content (P 0.05) for in vitro dry matter digestibility, but NDF digestibility was higher (P<0.01) for G1 treated with CTR, AAC and ENZ, G2 treated with CTR, and G4 treated with ENZ than the rest of the treatments. As a conclusion, the study shows depending on the focus, all the four groups of the silages i.e., energy silages (G1), protein silages (G2), easily degradable silage (G3), and balanced silage (G4) can be used in livestock feeding.