The effect of dry matter content and silage additives on the fermentation of grass silage on commercial farms

Abstract

A total of 1713 samples of silage from commercial farm silos were analysed to investigate the effect of dry matter (DM) content and chemical additives on fermentation as measured by ammonia-N concentration and pH, Increasing DM content without additive use had a major beneficial influence upon fermentation. When silage DM contents were greater than 260 g kg~' 83% of silages were well fermented, with average ammonia-N concentrations of 94 g (kg total N)"' and pH 4 36, With diminishing DM concentration the proportion of well fermented silages declined. In the DM range 220-260 g kg"' 67% of silages were well fermented with ammonia-N concentrations of 125 g (kg total N)-' and pH 4 30, in the DM range 180-220 g kg"' 48% were well fermented with ammonia-N at 151 g (kg total N)~' and pH 4 38 and with DM below 180 g kg"' no silages were well fermented with ammonia-

The effect of wilting and silage additives on the fermentation of autumn made grass silage ensiled in bunkers on commercial farms in South Wales 1983‐85

“…The present survey results support those of Ibbotson (1976) andHaigh (1987) in that use of sulphuric acid-I-formalin provided little or no reduction in pH or ammonia-N compared with untreated silages with DM levels below 220 g kg-'. They disagree, however, with other results (Haigh and Parker, 1985) and the commercial farm silage results for wet silages reported by Crawshaw and Hughes (1978) when sulphuric acid-f formalin treatment significantly reduced silage pH values compared with untreated silages.…”

“…The results presented here for formic acid treatment in terms of reduction in pH and ammonia-N are similar to those for wet commercial farm silages reported by Ibbotson (1976) and Crawshaw and Hughes (1978), but far better than those reported by Haigh (1987). However, in the latter work low and uneven rates of application were used, whilst in the present work high application rates were used for all the grass ensiled.…”

“…They disagree, however, with other results (Haigh and Parker, 1985) and the commercial farm silage results for wet silages reported by Crawshaw and Hughes (1978) when sulphuric acid-f formalin treatment significantly reduced silage pH values compared with untreated silages. Both results, however, apply to silage made from grass with a much higher WSC than in the present work (Haigh and Parker, 1985;Haigh, 1987). Therefore, although the application rate of the sulphuric acid + formalin additive in the present survey was near the manufacturers top recommended rate (Agricultural Development and Advisory Service, 1987) it would only reduce grass pH under laboratory conditions to 5-17 (Crawshaw, 1977).…”

“…Using this criterion, only formic acid with or without formalin treatments produced wellfermented silages. The pH values were, however, generally above the pH 4 2 level required for a good fermentation for silage with DM below 210 g kg-' (Haigh, 1987). Nevertheless lactic acid and total acid levels were similar to those found in silages treated with formic acid with or without formalin additives (McDonald, 1981;Haigh and Parker, 1985).…”

“…Details of the questionnaire form can be supplied upon request. Silage samples were taken after the silage had been made for at least 6 weeks as described by Haigh (1987). Random grass samples taken by cutting with shears at harvesting, together with unpublished data for ADAS plots in 1983-85, were used to indicate grass quality for ensilage.…”