CASE: Future-proofing silage: Controlling silage fermentation to improve its quality and reduce the risk of mycotoxins in a changing climate

Ensiling is used to preserve forages through fermentation and ensure a year-round feed supply with grass silage being the most common forage fed in the UK (Defra, 2025). Understanding and controlling the microbial and biochemical process involved in ensiling grass silage is therefore critical. The inoculation of grass at harvest with bacteria that promote a hetero or homofermentative fermentation presents an opportunity to more predictably control the ensiling process and improve forage quality. However, under certain conditions fungal growth can occur within silage and at feed out leading to the production of mycotoxins which is predicted to increase due to climate change (Kos et al., 2023). Mycotoxins are secondary fungal metabolites that can impair animal health, fertility and productivity and may enter the human food chain through milk and meat products. Most mycotoxin research has focused on maize silage with limited information available on grass silage or their effects on digestion, dairy cow health and productivity (Manni et al., 2023).

The aims of this studentship will be to investigate the effects of manipulating the fermentation of grass silage on the nutritive value and mycotoxin contamination of silage, and determine the subsequent impact on animal health and performance. Mini scale silos will be used to investigate the effects of fermentation pathways on silage quality and mycotoxin production. This will be followed by in vitro fermentation studies to investigate the effects on digestion to identify key treatments and mitigation strategies that will then be used in dairy cow performance studies.