Effect of Harvest Age on Forage Production and Silage Quality of Pearl Millet Hybrid in Cerrado Biome

Pearl millet (Pennisetum glaucum L.) is a promising crop for silage production in the Cerrado biome, but its use is still limited, and the ideal age for ensiling has not been well defined. This study aimed to evaluate the ADRf 6010 pearl millet hybrid at four harvest ages for ensiling: 75, 85, 95, and 105 days after planting (DAP). Forage production (green and dry forage mass), chemical composition, and fermentation parameters were analyzed. Harvested forage was chopped into 2.0 cm particles and treated with a concentration of 1 × 105 CFU/g (Colony Forming Units; Lactobacillus plantarum CNCM I-3736 and Pediococcus acidilactici CNCM I-4622) of fresh forage. Forage mass increased linearly with harvest age. At 105 days of growth, the crop yielded 65,980 kg/ha of fresh forage and 15,569 kg/ha of dry matter. The dry matter (DM) and neutral detergent fiber (NDF) concentrations also increased with advancing harvest age. The concentrations of crude protein (CP), non-fibrous carbohydrates (NFC), and in vitro dry matter digestibility (IVDMD) decreased with increasing harvest age before ensiling. In the silages, pH, ammoniacal nitrogen (NH3-N), effluent loss, gas losses, and silage density decreased linearly, while DM recovery increased. With advancing harvest age, there was a positive linear increase in the concentrations of DM, NDF, and acid detergent fiber (ADF). On the other hand, CP, NFC, and IVDMD showed a negative linear trend. Based on the results, the ADRf 6010 pearl millet hybrid demonstrated high forage yield and favorable fermentative characteristics when harvested at different growth stages during the summer season. Advancing harvest age resulted in increased forage mass, dry matter content, and dry matter recovery, along with reduced fermentation losses such as effluents and gases. Although later harvests led to reductions in crude protein concentration and in vitro digestibility, these effects were compensated for by the higher dry matter yield per hectare and better preservation conditions. Thus, ADRf 6010 pearl millet is a promising crop for silage production under tropical conditions.