Mycotoxins in dairy cows: the role of rumen

Margaux Lecolinet, Global Marketing Manager for Mycotoxin Management, Adisseo

Damien Prévéraud, Global Scientific Manager for Mycotoxin Management, Adisseo

1. Rumen protects dairy cows against mycotoxins… only partially

Mycotoxins are toxic metabolites, produced by fungi, that can develop in grains and forages. The most well-known and probably the most feared type of mycotoxins in dairy production are aflatoxins, and aflatoxin B₁ (AFB₁) in particular. When fed to cows, it is metabolically transformed in the liver into aflatoxin M₁ (AFM₁), which is hepatotoxic and carcinogenic. AFM₁ can be carried over into milk, and this can result in severe public health issues and direct losses for producers.

However, aflatoxins are not the only mycotoxin group of concern. Six other main families of mycotoxins have been identified: ochratoxins, zearalenone, two trichothecene groups (including deoxynivalenol (DON) and T-2 toxin), fumonisins and ergot alkaloids. Ruminants are naturally partially protected against some mycotoxins, thanks to the ability of the rumen microflora of such animals to produce enzymes that are capable of detoxifying some mycotoxins. However, most mycotoxins are still a source of major concern regarding the health and performance of cows. The main types of mycotoxins, the sensitivity of dairy cows and their main target organs or systems are presented in Figure 1.