Assessing the impact of climate action mitigation strategies on key microbial pathogens in bovine production systems

Ireland aims for a fifty-one percent reduction in greenhouse gas emissions by 2030, with the agricultural sector tasked with achieving a twenty-five percent cut. In the bovine sector, current efforts focus on implementing feed additives to reduce both enteric methane emissions and emissions from stored slurry.

These interventions are expected to change the microbial ecosystem, potentially impacting zoonotic pathogens such as Shigatoxigenic E. coli, Salmonella spp, and Listeria monocytogenes. The resulting effects might be positive, reducing pathogen carriage and survival, or negative, enhancing pathogen survival or virulence.

A key area of study is the methane-reducing feed additive 3-nitrooxypropanol (3-NOP, Bovaer®), which has recently received positive feedback from EFSA in 2021. However, its full impact on the microbiome and bovine gut pathogens remains under investigation. Other additives with commercial potential include seaweed extracts like Asparagopsis, direct-fed microbials (such as lactic acid bacteria strains), essential oils, and halides.

The project also examines the impact of additives used in stored slurry. These include acidifiers and bioinoculants, which may affect the survival of zoonotic pathogens in waste, influencing pathogen recycling on grazing lands or during crop/horticulture production.

This research offers a crucial microbial safety assessment of these climate action interventions in the bovine production cycle.