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Digestibility of grass fibre increased by screw pressing in a bio-refinery

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In this study, the effects of screw-pressing prior to ensiling and days of regrowth of perennial ryegrass on fibre digestibility were investigated. Six rumen and duodenal fistulated, multiparous Holstein cows (176±93 days in milk;
mean ± SD) were used in an incomplete 6×4 Latin square design with four periods and a 2×3 factorial arrangement of treatments. The factors were developmental stage of grass at harvest [early (ERL; 35 days of regrowth) and late (LAT; 44 days of regrowth)] and processing prior to ensiling [traditional grass silage (GS; mowed, wilted, and chopped), pulp pressed once (1×P; fresh grass processed using twin-screw press producing the two fractions pulp and green juice), and pulp pressed twice (2×P; half of 1×P was soaked in water and processed a second time)]. Grass of all six treatments ensiled for four months before the digestibility experiment started. A total mixed ration with experimental silages, soybean meal, rolled wheat, and minerals (65.0, 6.60, 26.6, and 1.80% of DM, respectively) was fed in periods of 21 days duration. Two markers (titanium dioxide and chromic oxide) were dosed in the rumen twice a day to determine flow of digesta in duodenum and output in faeces. A model including developmental stage, processing, developmental stage × processing, and period as fixed effects, and cow as random effect was analysed in R. Across
developmental stage, DM intake was lower (14.9 vs 17.5 kg/d; P<0.01) and NDF intake was higher (7.07 vs 5.92 kg/d; P<0.01) for 2×P compared to GS. For rumen and total tract NDF digestibility, an interaction was found between
developmental stage and processing (P<0.05). No effect of processing was observed for ERL (average rumen and total tract NDF digestibility were 73.3 and 76.5%), but an increase was observed with increased processing intensity
for LAT (66.2, 71.5, and 76.6% for rumen, and 71.6, 73.8, and 78.3% for total tract NDF digestibility, for GS, 1×P, and 2×P, respectively). Across developmental stage, the amount of NDF digested in the total tract was higher for 2×P
compared to GS (5.47 vs 4.36 kg/d; P<0.01). The study showed that processing can increase intake of fibre and that processing has the greatest effect on fibre digestibility in more developed grass.
Original languageEnglish
Title of host publicationBook of Abstracts of the 72nd Annual Meeting of the European Federation of Animal Science
EditorsE. Strandberg, L. Pinotti, S. Messori, D. Kenny, M. Lee, J.F. Hocquette, V.A.P. Cadavez, S. Millet, R. Evans, T. Veldkamp, M. Pastell, G. Pollott
Number of pages1
PublisherWageningen Academic Publishers
Publication yearAug 2021
ISBN (print)978-90-8686-366-2
ISBN (Electronic)978-90-8686-918-3
Publication statusPublished - Aug 2021
Event72nd Annual Meeting of the European Federation of Animal Science - Congress Centre Davos, Davos, Switzerland
Duration: 29 Aug 20213 Sep 2021


Conference72nd Annual Meeting of the European Federation of Animal Science
LocationCongress Centre Davos
SeriesEAAP Book of Abstracts

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