Intake and digestibility by sheep, in situ disappearance in cannulated cows, and chemical composition of crabgrass hayed at two moisture concentrations and treated with a non-viable Lactobacillus–lactic acid additive

Crabgrass (Digitaria ciliaris [Retz.] Koel.) is a high-quality warm-season annual that can be used as hay, but field curing time may be lengthy compared with other forages. A 1.6-ha field of common crabgrass was divided into 12 plots (8.25 m × 50 m) that were used in a randomized complete block design with a 2 × 2 factorial treatment arrangement to determine the effects of a non-viable Lactobacillus–lactic acid additive and moisture concentration at baling on heating characteristics and pre- and post-storage chemical composition. Half of the plots within each block were treated with 0.081 ml/mg dry matter (DM) of a solution containing 110 g lactic acid/kg and non-viable Lactobacillus acidophilus at the time of mowing (T) and half were not treated (U). Within T and U plots, half were baled in small square bales at 163 g moisture/kg DM (L) and half at 251 g moisture/kg DM (H) of moisture. Six bales per plot were selected at random, weighed, and stored in separate insulated 6-bale stacks. Core samples were taken from 3 bales initially and 3 bales post-storage. Initial bale moisture concentrations were greater (P<0.05) and initial neutral-detergent fiber (NDF) concentrations were lower (P<0.05) from H vs. L. Post-storage concentrations of NDF and acid-detergent insoluble N (ADIN; g/kg DM and g/kg N), were greater (P<0.05) from H vs. L. Dry matter intake in sheep was unaffected (P>0.05) by either treatment, but DM digestibility and digestible DM intake were both positively affected (P<0.05) by the spray treatment. In addition, DM digestibility was also affected (P<0.05) by moisture, with H>L. In situ DM disappearance was largely affected by spray treatment × moisture interactions (P<0.05). The immediate soluble fraction and effective ruminal disappearance were greater (P<0.05), and the undegraded portion in the rumen was less (P<0.05) for HT compared to HU, indicating a positive relationship between applied spray treatment and digestibility of high-moisture crabgrass. Treating crabgrass with the additive at mowing may not affect forage chemical composition, but may improve digestibility in hay baled at elevated moisture levels.