373. Impact of Irrigation, Nitrogen Management and Ensiling Days on Silage Quality in Warm Season Annual Forages.

Abstract Ensiling fresh forage to produce silage is an effective strategy to ensure a stable, long-term feed supply. Maize (Zea mays) silage is generally preferred because of its high nutritional quality and palatability for cattle; however, its productivity and nutritional quality are drastically reduced under water-limited conditions. Sorghum (Sorghum bicolor) and pearl millet (Pennisetum glaucum) are promising alternative forages for silage because of their low-input requirements under sub-optimal conditions. The aim of this study was to compare the silage fermentation profiles of forage sorghum, pearl millet, and maize hybrids, and to assess the effects of irrigation and N fertilization, and ensiling duration on silage yield, quality, and antinutritional factors, with particular emphasis on prussic acid-free (PF) sorghum. Although irrigation and N fertilization affected silage quality, forage type and ensiling length exerted stronger overall influence on silage nutrient profiles. In general, dry matter remained relatively stable during ensiling, while protein, ammonia, starch, energy traits, digestibility, and fermentation acids increased with ensiling. In contrast, undegradable protein, fiber, lignin, soluble carbohydrates, minerals, and NO₃⁻ declined with ensiling. Limited irrigation treatments, irrespective of N fertilization, resulted in higher NO₃⁻ levels and lower starch and carbohydrate accumulation. Pearl millet was high in proteins and minerals, maize was energy-rich, non-PF sorghum was high in fiber, and PF sorghum exhibited the highest starch and non-fibrous carbohydrate contents along with lower NO₃⁻ levels. The potential of PF sorghum to inhibit or minimize the accumulation of antinutritional factors, combined with its ability to thrive under sub-optimal environments, makes it an ideal forage for semi-arid regions.