Effects of cut height and inoculant application on yield, nutrient composition, fermentative profile, and in vitro degradability of brown midrib whole-plant corn silage

Abstract

Our objective was to determine the effects of cut height and inoculant application on brown midrib (BMR) whole-plant corn silage (WPCS) quality. Corn was harvested at 2 cut heights: low-cut height (LC, 30.5 cm) and high-cut height (HC, 56 cm). Three commercially available inoc- ulants were used as treatments: Lactobacillus plantarum and Pediococcus pentosaceus (SA), Propionibacteria freud- enreichii and Pediococcus pentosaceus (P2), and Lactoba- cillus buchneri and Pediococcus pentosaceus (B500). Mini silos were opened at 5 fermentation time points: 0, 2, 5, 30, and 90 d. Gross yield and DM yield of BMR WPCS decreased for HC compared with LC. The HC increased the concentrations of BMR WPCS DM, CP, and starch and predicted milk yield; decreased the concentration of NDF and ADF; and tended to increase NDF digestibility in 30-h in vitro digestion. The greater nutritive value of the HC possibly allows for an increased quantity of forage to be included in the TMR and de- creases the amount of ground corn needed to be added to the diet, potentially providing an economic benefit. The HC had lower acetic acid concentration compared with LC for CON and B500. The HC tended to have lower total acids and lactic acid compared with LC for all treatments. There was an interaction of height × length of storage for the fermentative profile. The increased acid concentra- tions during ensiling were expected and the greater acids concentration for LC compared with HC was probably due to more water-soluble carbohydrates for LC, which should have improved fermentation. The HC yielded a WPCS with better nutritional value; however, the fermen- tative profile was reduced compared with LC. Our results indicate that in the present conditions, the use of these particular inoculants did not improve WPCS fermentation profile.