Effect of herbage water‐soluble carbohydrate content and weather conditions at ensilage on the fermentation of grass silages made on commercial farms

Abstract

A total of 1009 samples of silage made in bunker silos on commercial farms between 1972 and 1978 was analysed to investigate the effect of herbage water‐soluble carbohydrate content (WSC) and weather conditions at ensilage on fermentation as measured by ammonia‐N concentration and pH of first‐cut grass silages. Silage dry matter (DM) content had the major effect on fermentation. Factors influencing silage DM were rainfall and hours of sunshine during silage making, and DM content of the grass cut. WSC content of herbage ensiled also had a significant effect on subsequent fermentation. The major influences on herbage WSC were hours of sunshine and rainfall during the growing season. The effect of chemical additives, albeit at poorly defined and often inadequate rates, was small in comparison to that of silage DM. The minimum DM necessary to produce well‐fermented silage without additive was approximately 260 g kg−1. Use of formic acid significantly reduced this requirement to 240 g kg−1 and to 252 g kg−1 for sulphuric add + formalin. The results indicate that the minimum herbage WSC necessary to prevent a clostridial fermentation developing in silage with a DM content of 230 g kg−1 is approximately 37 g kg−1 without additive and 30 g kg−1 with formic acid. It is concluded that on commercial farms, weather conditions i.e. amount of rainfall and sunshine prior to and at ensilage, have a greater effect on subsequent silage fermentation than additive use.

Mixed sugarcane and elephant grass silages with or without bacterial inoculant

“…McCullough (1977) recommended soluble carbohydrate contents greater than 80 g/kg of the dry matter and moisture content close to 700 g/kg as potential for ensilage of a plant. However, Haigh (1990) suggested that there was an inverse relation between the need for sugars and the dry matter content of the forage to obtain proper fermentation. Van Soest (1994) reported that the SC: buffering capacity ratio should be high, to obtain good-quality silage, if the dry matter content of the forage is reduced.…”

Uso de diferentes aditivos em silagem de capim-elefante

“…Os carboidratos solúveis são o mais importante substrato para boa fermentação da forragem. O conteúdo de carboidratos solúveis de uma forrageira é considerado com um parâmetro indicador da qualidade da forragem para ensilagem, sendo necessária uma concentração mínima de 2,5 a 3,0% na MS (HAIGH, 1990). Segundo o mesmo autor, existe uma relação inversa entre a necessidade de carboidratos solúveis e o teor de matéria seca da forragem para que ocorra uma boa fermentação.…”

Ensiling of elephant grass with soybean hulls or rice bran

“…In contrast, the addition of rice bran to chopped elephant grass resulted in a significant linear increase (P < 0.05) in the WSC content of material, with a 0.177% increase for every 1% of rice bran added (Table 1). The WSC content is considered an indicator of the quality of the forage to be used for ensiling, with a minimum concentration of 2.5 to 3.0% required (HAIGH, 1990). Despite some elephant grass cultivars possessing a WSC content greater than 16% of DM (Taiwan A-148), reasonable silages have been produced when the cultivar used has a WSC content below 13% to 15%.…”