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Effect of lignosulfonates on the dry matter loss, nutritional composition, and microbial counts of high-moisture alfalfa silage.

A. Y. Leon-Tinoco

Abstract:

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Effect of lignosulfonates on the dry matter loss, nutritional composition, and microbial counts of high-moisture alfalfa silage.
A. Y. Leon-Tinoco*1, B. C. Guimar�es2, S. T. R. Almeida2, D. C. Reyes1, S. Rivera1, R. Hollandsworth1, M. Killerby1, Z. X. Ma3, B. Perkins1, S. L. Annis1, C. Wu4, C. Knight1, A. Lichtenwalner1, D. Skonberg1, J. J. Romero1. 1University of Maine Orono, ME, 2University of Lavras Lavras, Minas Gerais, Brazil, 3University of Florida Gainesville, FL, 4University of Delaware Newark, DE.

Our objective was to evaluate the effect of 2 technical lignins, sodium and magnesium lignosulfonate (NaL and MgL, respectively) and an inoculant mixture (INO) on high moisture alfalfa silage spoilage. Treatments were untreated (0%), NaL and MgL applied independently at 0.5, 1, and 1.5 (% wt/wt, fresh basis) and INO (Pediococcus pentosaceus and Lactobacillus plantarum; 5 and 4 log cfu/fresh alfalfa g, respectively). An alfalfa field was divided into 5 plots (blocks), and unwilted alfalfa was chopped, treated (randomly within block), and ensiled for 229 d in mini-silos (0.29 L). Data were analyzed as a randomized complete block design (5 blocks) and differences were declared at P ≤ 0.05. Linear (L) and quadratic (Q) polynomial contrasts were used to determine dose rate effects for NaL and MgL and orthogonal contrasts for INO effects. At d 0, increasing NaL dose from 0 to 1.5% increased DM (21.9 to 22.7 � 0.12%; L) and decreased mold counts (4.48 to 3.62 � 0.142 log cfu/fresh g; L). No treatment effects were observed on yeast (6.94) and lactic acid bacteria counts (7.04 log cfu/fresh g), sugars (6.15), CP (21.7), and NDF (43.2% of DM). At opening (d 229), increasing the NaL dose from 0 to 1.5% increased pH (4.33 to 4.56 � 0.018; L) and DM (18.9 to 19.9 � 0.19%; L), and decreased lactic acid (8.80 to 7.13 � 0.24% of DM; L) and the lactic to acetic acid ratio (2.39 to 1.78 � 0.07; L) but did not affect DM losses (~11.8 � 0.67%). MgL increased pH (4.33 to 4.45 � 0.018; L) and DM losses (11.28 to 14.05 � 0.67%; L), and decreased lactic acid (8.80 to 6.74 � 0.24%). Neither NaL nor MgL had an effect on sugars (~0.67 � 0.07%), NH3-N (~10.9 � 0.54% of N), acetate (~3.82 � 0.13% of DM), and ethanol (~1.02 � 0.04% of DM). Compared with untreated (P ≤ 0.05), INO increased DM losses (11.28 vs. 13.7 � 0.67%), pH (4.33 vs. 4.46 � 0.018), and decreased lactic acid (8.8 vs. 7.37 � 0.24%) and sugars (0.8 vs. 0.45 � 0.07% DM). Across treatments, yeasts and molds were below 2 log cfu/fresh g. In conclusion, additives tested did not improve the preservation of high moisture alfalfa silage, with INO and MgL actually increasing DM losses relative to untreated.

Keywords: alfalfa, silage, lignosulfonates.