Mesquite (Prosopis L.) is considered an invasive browse species in most of the American Southwest. Mechanical intervention removes yields an excess of organic debris. Anecdotal evidence in the past has supported using such browse as feed for livestock. Thus, our objectives were to (1) determine the nutritive value and fermentation characteristics of silage produced with mesquite biomass, and (2) evaluate solvent treatment of mesquite biomass prior to ensiling. In Experiment 1, we evaluated mesquite inclusion rate (0, 250, 500, 750, or 1000 g kg−1 DM), length of fermentation (28, 56, or 84 d), and silage inoculant. In Experiment 2, we evaluated the effects of mesquite pre-treatment with acid (H2SO4) or alkali (NaOH) solutions. Concentrations of NDF, ADF, and ADL, as well as IVTD, decreased (p < 0.05) with increasing mesquite inclusion. However, 250 g mesquite kg−1 DM did not differ from grass silage. There was no effect (p > 0.05) of inoculation, though increasing length of incubation did increase (p < 0.05) VFA production and decrease (p < 0.05) silage pH. Solvent treatment did not improve ensiling properties. Results are interpreted to mean that mesquite biomass may be effectively incorporated into silage at levels up to 250 g kg−1.

Mesquite (Prosopis glandulosa Torr.) is considered an invasive browse species in most of the American Southwest. Over the past several decades, mesquite has spread rapidly in Texas, leading to destruction of native grasslands. In addition to trying to manage its encroachment on grazinglands, producers have been known to use mesquite wood in times of drought as a feed source for livestock, specifically in cow/calf production. This also represents a potential sustainable solution to dealing with debris from brush control measures. Thus, our objective was to evaluate the inclusion of chipped mesquite wood as a partial grass replacement in silage production. This experiment used a factorial treatment structure of silage inoculant (yes, no), grass replacement (0, 25, 50, 75, 100%), and length of incubation (28, 56, 82 d). Bermudagrass [Cynodon dactylon (L.) Pers. cv. Coastal] was used as the grass base in the silage mixtures. Samples were incubated in a convection incubator at 29.4°C for their respective incubation lengths. Following incubation, each sample was assayed for NDF, ADF, ADL, CP, and IVTD, as well as a silage acid profile. There was no effect of inoculation, grass replacement, or incubation time (P ≥ 0.13) on CP (μ = 10%), nor was there an effect of inoculation or grass replacement (P ≥ 0.67) on NDF (μ = 70%). Both ADF and ADL increased (P &lt; 0.05) with increasing inclusion of mesquite wood. In vitro true digestibility decreased (P &lt; 0.05) with increasing inclusion of mesquite wood (50% from grass silage; 40% from mesquite silage). Results are interpreted to mean that mesquite wood may be used as a grass replacement in silage production at low inclusion levels.