Relationship between climate and mycotoxin contamination

Livestock contribute to climate change mainly by releasing greenhouse gases. Climate change, in turn, negatively impacts livestock production through higher temperatures, drought, altered rainfall, and increased disease prevalence. Mycotoxin contamination of feed is part of this puzzle. Mycotoxins, such as deoxynivalenol (DON) and zearalenone (ZEA), cause feed refusal and decreased productivity in ruminants. However, there are limited studies correlating mycotoxin contamination with climate. Therefore, we aimed to study the correlation of climate variables with DON and ZEA levels in corn matrices such as silage, whole grain, mashed grain, and mashed cob with husk. For this, 11688 samples were collected by the Regional Breeders Association of Lombardy, from 2014 to 2023. Of this, 7504 samples were studied for DON and 4917 for ZEA contamination using ELISA. The contamination level was statistically analysed using Tobit regression and correlated with climate variables. We found that whole and mashed grains were the most contaminated by DON (1389- 1767 ppb). However, these values are less than 5000 ppb, the maximum levels recommended by the European Union (EU) for large ruminants. ZEA levels in corn matrices were also below the EU safety recommendations of 500 ppb. Climate variables were correlated to both DON and ZEA contamination in corn matrices. Specifically, cumulative monthly relative humidity (>80%, at two meters) was positively related to both DON and ZEA contamination. Conversely, consecutive dry days were negatively related to DON and ZEA contamination in corn. In conclusion, DON and ZEA occur in the corn matrices of Lombardy, but at levels below the EU safety threshold. Our findings highlight the relationship between specific climate variables, such as humidity and dry period, with mycotoxin contamination in corn. Monitoring individual corn matrices in relation to the climate is a key mitigation strategy to combat mycotoxin contamination.