The effect of type of additive on rumen fermentation and digestion of grass silage in cattle

Authors

• Aila Vanhatalo Agricultural Research Centre of Finland, Institute of Animal Production, SF-31600 Jokioinen, Finland
• Tuomo Varvikko Agricultural Research Centre of Finland, Institute of Animal Production, SF-31600 Jokioinen, Finland
• Ilmo Aronen Agricultural Research Centre of Finland, Institute of Animal Production, SF-31600 Jokioinen, Finland

DOI: https://doi.org/10.23986/afsci.72433

Abstract

Four grass silages made from a second cut cocksfoot-timothy grass were ensiled with the application of water, i. e., without additive (NA), formic acid (FA), lignosulfonate + formic acid + acetic acid (LFA) and cellulase + glucose oxidase enzymes (E), The silages were fed at maintenance level to four dry cows, which had been equipped with a rumen cannula and a simple T-shaped duodenal cannula, in a digestibility experiment designed as a 4x4 latin square. The silages and a mixture of barley and oats (1:1) were given at a ratio of 70:30 on a dry matter basis. All the silages were well preserved, but fermentation in the silo was more restricted in silages ensiled with acid-based additives. The enzyme treatment resulted in reduced levels of cell wall contents compared to the other silages. The apparent digestibilities of organic matter (OM) and neutral detergent fibre with E silage were higher (P<0.05) than with the other silages. The microbial N flow at the duodenum was significantly higher (P<0.001) with the LFA diet compared to the other diets (NA 52; FA 53; LFA 66 and E 47 g N/d) and the efficiency of microbial protein synthesis tended to be lower with the E diet compared to the other diets (NA 31; FA 31; LFA 38 and E 20 g N/OM apparently digested in the rumen). The molar proportion of acetate in the rumen was significantly higher (P<0.001) and the proportion of propionate significantly lower (P<0.001) with acid silages than with E and NA silages. The proportion of butyrate was significantly higher with E silage compared to the others.