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

In this experiment, we evaluated the effects of sodium lignosulfonate (NaL) and magnesium lignosulfonate (MgL) applied independently at 0, 5, 10, and 15 (g/kg, fresh weight basis) and an inoculant (INO) on high-moisture (DM: 219 g/kg, fresh weight basis) alfalfa (Medicago saliva L.) silage nutrient preservation. The INO consisted of Pediococcus pentosaceus and Lactobacillus plantarum applied at a rate of 4.95 and 4.00 log cfu/g (fresh weight basis), respectively. Data were analyzed as a randomized complete block design (RCBD; 5 blocks) and linear and quadratic 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 15 g/kg increased linearly DM (219-227 g/kg) and decreased linearly mold counts (4.48-3.62 log cfu/g; fresh weight basis). No treatment effects were observed on lactic acid bacteria counts (7.04 log cfu/g; fresh weight basis), water soluble carbohydrates (61.5), and aNDF (432 g/kg of DM). After 229 d of ensiling, both MgL and INO increased DM loss ((x) over bar = 13.7 and 13.7 vs 11.3% of DM) due to a lower production of lactic acid ((x) over bar = 75.5 and 78.3 vs 92.3 g/kg of DM, respectively) which resulted in a higher pH relative to untreated silage ((x) over bar = 4.41 and 4.46 vs 4.33; respectively). Increasing doses from 0 (6.42) to 15 g/kg for both NaL (6.90) and MgL (7.06 log cfu/g; fresh weight basis) resulted in linear and quadratic increases of lactic acid bacteria counts, respectively. These counts were also higher in INO treated silages (6.98 log cfu/g; fresh weight basis), relative to untreated silage. Furthermore, both NaL and MgL decreased in vitro ruminal total volatile fatty acid concentration (x = 87.0 and 93.1 vs 97.1 mM; respectively), compared with the untreated silage. The greater acidification in untreated silage prevented additives tested from reducing the generation of NH3-N ((x) over bar = 110 g/kg of N) during ensiling. Overall, none of the additives tested improved the preservation of high-moisture alfalfa silage nutrients beyond what was observed in untreated.

Automated summary

This experiment evaluated the effects of different additives on the preservation of high-moisture alfalfa silage nutrients. The results showed that the addition of sodium lignosulfonate and magnesium lignosulfonate did not improve the preservation of the silage.