PS10-10. Warm-season Forage Mixtures Effects on Silage Nutritive Value and Fermentation Characteristics.

Abstract

The objective of this study was to evaluate the effects of different warm-season forage mixtures on silage nutritive value and fermentation characteristics. The study was conducted at the Texas A&M AgriLife Research and Extension Center in Stephenville, TX, from May to September 2025. Treatments were of four warm-season forage mixtures: 1) ‘S72’ sorghum sudangrass (SO; Sorghum spp.) + ‘Crescent sun’ sunn hemp (SH; Crotalaria juncea L.) + ‘Camello’ brachiariagrass (B; Urochloa spp.), SOSHB, 2) SO + SH + Spain gunieagrass [G; Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs] SOSHG, 3) SO + Red mini rattlepod (R, Crotalaria ochroleuca G. Don.) + B, SORB, and 4) SO + R + G, SORG, distributed in a randomized complete block design with four replicates. Plots were seeded in May 2025 and harvested at 20-cm stubble height every 6 weeks. Forage from the second harvest (11 September 2025) was chopped to a particle size of 5 to 10 cm and packed into mini-silos (aluminum containers with rubberized lids) to a 600 kg (as fed)/m³ density. Silos were opened after 60 days and samples analyzed for nutritive value and fermentation characteristics. There was no difference in herbage accumulation (mean = 6,400 kg/ha, SE = 900, P = 0.95), NDF (mean = 59.2%, SE = 1.61, P = 0.91), and TDN (mean = 56%, SE = 0.47, P = 0.84); however, ADF was greater or tended to be greater (P < 0.10) for SOSHG (41%) than SORB (38%) and SORG (38%), but it did not differ from SOSHB (40%). The CP for SOSHG (11.5%) was greater (P < 0.03) than SORG (8.8%) and SORB (8.1%) but it did not differ from SOSHB (10.4%). The SOSHB did not differ (P = 0.14) from SORG. There was no difference among treatments for pH (mean = 4.07, SE = 0.21, P = 0.56), lactic acid (mean = 8.35, SE = 1.02, P = 0.11), acetic acid (mean = 1.5, SE = 0.21, P = 0.64), or butyric acid (mean = 0.01, SE = 0.01, P = 0.84). However, total acids did not differ (P > 0.25) among SORG (11.7%), SORB (10.3%) and SOSHB (10.0%), but SORG was greater (P = 0.01) than SOSHG (7.5%). There was no difference (P > 0.05) in ammonia-N concentrations among SORB (5.7%), SOSHB (6.7%), and SORG (6.7%) but they were greater (P < 0.04) than SOSHG (4.2%). The SOSHG treatment had slightly better fermentation characteristics with greater CP concentration, but all treatments had adequate fermentation for proper silage preservation.