Influence of wilting on chemical and microbial parameters of grass relevant to ensiling.

Abstract

Plots of Lolium perenne were subjected to the normal farm routine for making wilted silage. The grass was sampled periodically during (generally moist) wilting and analysed for chemical and microbial factors. The daily increase of the ammonium-N content was 5.8 g/kg N; the CF content also tended to increase during wilting (6 +or- 4.3 g/kg DM), though the correlation was poor. The sugar content of the grass and the in vitro digestibility decreased during wilting (9 +or- 6.1 g/kg DM per day and 1.1 +or- 0.11 percentage units/d, resp.). Counts on rogosa agar increased on av. by 0.24 +or- 0.16 logarithmic units (LU)/g DM per day and on MRS agar by 0.13 +or- 0.17 LU/g DM per day. Enterobacteria enumerated on violet red bile glucose agar increased by 0.23 +or- 0.18 LU/g DM per day. Inoculation by spraying the standing grass as an alternative to application on the forage harvester was investigated. In 4 separate trials the standing grass was sprayed with approximately 6.6 LU/g DM of a silage inoculant containing Lactobacillus plantarum. During wilting the counts on rogosa agar declined by 0.72 +or- 0.33 LU/g DM per day and on MRS agar by 0.65 +or- 0.35 LU/g DM per day whereas the counts on the uninoculated control field increased by 0.17 +or- 0.19 and 0.17 +or- 0.17 LU/g DM per day for the rogosa and MRS media, resp. It was concluded that inoculation of the standing grass was probably only useful in combination with a short wilting period. (Abstract retrieved from CAB Abstracts by CABI’s permission)