ARS | Publication request: In Vitro Gas Production and Bacterial Biomass Estimation of Lucerne Silage Inoculated with One of Three Lactic Acid Bacterial Inoculants

Submitted to: International Silage Conference
Publication Type: Abstract
Publication Acceptance Date: February 20, 2005
Publication Date: July 3, 2005
Citation: Contreras-Govea, F.E., Muck, R.E., Filya, I., Mertens, D.R., Weimer, P.J. 2005. In vitro gas production and bacterial biomass estimation for lucerne silage inoculated with one of three lactic acid bacterial inoculants. In: Park, R.S., Stronge, M.D., editors. Silage production and utilisation, XIVth International Silage Conference, July 3-6, 2005, Belfast, Northern Ireland. p. 207.

Technical Abstract: An in vitro method was used to study differences in potential ruminal fermentation among alfalfa silages inoculated with different microbial inoculants. Alfalfa was ensiled in glass jars in two trials [48 and 39% dry matter (DM)] with four treatments [three microbial inoculants (L. pentosus, MTD1, 1174) plus uninoculated control]. The alfalfa silages (1-g samples, wet-ground, frozen until analyzed) were incubated in sealed 160 ml Wheaton bottles. In vitro gas kinetics were carried out at 39°C, and gas pressure was measured at 3, 6, 9, 24, 48, and 96 h. At 9 h, 4 bottles of each treatment were opened, pH measured, and microbial biomass yield estimated using the method of Blümmel et al. (1997). On average, the gas production increased linearly during the first 9 h of fermentation and was greater in control than inoculated silage. Although harvests were not statistically compared, greater gas production (GP), in vitro true digestibility (IVTD), and microbial biomass yield (MBY) were observed on second cut than first cut due to the higher quality of the second cut (282 vs. 391 g neutral detergent fiber/g DM). Even though treatment differences within harvests were not always significant, the trend among treatments was the same, lower gas production and gas production efficiency (ml/g DM digested) on MTD1 and L. pentosus than control and 1174. In addition, alfalfa inoculated with MTD1 had consistent trends toward higher IVTD and MBY than those of the control. Methane production was different among treatments, but trends were not consistent between cuts. The results indicate that microbial inoculants, particularly MTD1, produced silages that shifted in vitro rumen fermentation toward less gas production and more microbial biomass than untreated silages.