Determination of Microbial Gas Production, Fermentation Kinetics and Digestibility of Alternative Crop Silages

Authors: İSMAİL AKYOL, EMİN ÖZKÖSE, MEHMET SAİT EKİNCİ

Abstract: Microbial gas production (MGP), fermentation kinetics and DM loss of crop silages made from 7 different plant families (barley/pea, clover, grass, kale, lotus, lucerne, sainfoin) and 10 different refusals were determined. The pressure transducer technique (PTT) was used to measure the microbial gas production of fresh and ground silages and refusal samples at regular intervals throughout the 120 h incubation. The MGP of fresh and ground silages were similar (r^2 = 0.90). The maximum gas production was obtained from kale for ground and fresh silages whilst grass silage yielded the maximum gas pool for refusals. No differences were found between lag time but times to produce 50% and 95% gas pool were shorter with ground silages than with fresh silages and refusals. Total volatile fatty acid (VFA) production was notably lower for refusals compared to fresh and ground silages, yet ground and fresh silages yielded similar VFA levels. Dry matter (DM) losses of ground and fresh silages were similar. However, lower DM losses were observed for refusals. These results suggest that refusals could be used as a valuable and digestible feed-stuff for animals.

Keywords: Microbial gas production, fermentation kinetics, silage digestibility

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