Effects of common forage conservation methods on the alkaloid content of grassland growths infested by marsh horsetail (Equisetum palustre L.)

Abstract

The toxic sporophyte marsh horsetail (Equisetum palustre L.) increasingly infests moist and wet grasslands in Europe because of climate change, deeutrophication actions, and rewetting measures. Farmers, veterinarians, and authorities are insecure how to address this newly emerging situation, as only little information on toxin levels is available and information for no effect levels in livestock is based on outdated analytical methods. Hence, an important question is to what extent feed conservation measures could lead to a significant reduction in alkaloid levels. We investigated the capabilities of the two most common forage conservation methods, haying and ensiling, in reducing the initial alkaloid levels of fresh E. palustre contaminated biomass by field and lab-scale experiments simulating favourable and no favourable conservation conditions. Haying reduced the main alkaloid content up to 25% under ideal drying conditions only, probably due to friability losses of horsetail plant parts. However, under non-favourable weather conditions, alkaloid concentrations increased. Ensiling procedures reduced the main alkaloid content by less than 10%. There were no significant effects of ensilage duration or wilting degree on alkaloid content, despite a tendency toward a higher reduction in fresh silages. Common forage conservation methods have limited potential for degradation of the main marsh horsetail alkaloids. Our results give reason to consider other biomass utilization paths, such as composting or biomethanization for contaminated grassland growth instead of classical feed preparation.