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Conference paper - Peer-reviewed, 2017

The effect of nitrate content in forage on quality of silage fermentation

Knicky, Martin; Spörndly, Rolf; Eide, Fredrik; Gertzell, Bengt


Nitrate content in fresh herbage is one of the factors affecting fermentation in silage. Hein (1970) observed that ensiling of forages with low nitrate content often results in silages with high butyric acid contents. Butyric acid is an undesirable product of clostridia in silages indicating low silage nutritional quality (Pahlow et al., 2003). The effect of nitrate on butyric acid formation is derived from its degradation products. Nitrate undergoes reduction to nitrite which can be further converted to nitric oxide which is considered to be toxic for clostridia (Spoelstra, 1983). Therefore, crops high in nitrate decreases clostridial activity and, hence, butyric acid formation. The effect of nitrate content in fresh crops on butyric acid formation was summarized by Weissbach (1996). The summary shows high occurrence (78%) of butyric acid in silages made from crops low (<105) in epiphytic lactic acid bacteria (LAB) while containing <0.5 g NO3 per kg dry matter (DM). In contrast, incidence of butyric acid in silages from crops with similarly low LAB count but containing >1 g NO3 per kg DM was only 26%. Since it is common to use silage additives to improve or secure a proper ensiling process, it is interesting to study how different nitrate contents in fresh crops influence efficiency of silage additives. The objective of the study was, therefore, to study the effect of nitrite containing silage additives on silage quality with crops differing in nitrate content.


silage fermentation; nitrate content; quality

Published in

Book title: Proceedings of the 8th Nordic Feed Science Conference, Uppsala, Sweden
Publisher: Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences


8th Nordic Feed Science Conference