Biomass production and chemical composition of corn for silage in different reproductive stages

The ongoing professionalization of corn silage production is related to the specific productive and qualitative agronomic characteristics of the different hybrids available on the market, which define the dynamics of the appropriate moment for harvesting and making silage. This experiment evaluated the morphological and chemical composition, dry biomass production, and rumen degradation of plants from different corn hybrids, harvested at various reproductive stages. The experimental design was randomized blocks, in a 3 x 21 and/or 8 factorial arrangements, with three corn hybrids (B2401PWU, B2782PWU, and B2801PWU) associated with 21 and/or 8 harvest times, to evaluate productive and chemical parameters, respectively, at regular intervals, between the R1 and R6 reproductive stages, with four repetitions each. Changes in the reproductive cycle increased the production of dry biomass of forage and grains up to R5, reaching 26,536 and 10,142 kg.ha-1, respectively. This resulted in reduced average costs, reaching values of 0.51 R$ kg.DM-1. As the reproductive cycle advanced, there was a greater participation of grains and a dilution of structural components, resulting in reductions in NDF (44.44%) and ADF (27.66%) at R5. At this stage, the plant showed an average DM of 30%, while the grains had a DM of 56%. In situ degradability values were higher at the R4-R5 transition stage, while other chemical parameters were higher at R5 and/or before reaching physiological maturity at R6. In addition to the reproductive stages described in the literature, the transition stages are also relevant due to the physiological changes in the plant that affect the productivity and chemical quality of corn plants used for silage production.