Maize ready for shelling. [Christopher Kipsang, Standard]

After the long drought, livestock farmers can breathe a sigh of relief with the onset of rains. But there is a new challenge. With the warm and humid conditions, stored feed is likely to be attacked by fungi which when broken down produces aflatoxins. 

What are aflatoxins?

Aflatoxins are a group of toxic compounds that are produced by certain fungi of the genus Aspergillus. These fungi are commonly found in soil, decaying vegetation, and crops such as peanuts, maize, and cottonseed. They can also be found on hay and silage if not properly stored.

How do aflatoxins develop?

The development of aflatoxins begins when the Aspergillus fungi infect crops such as peanuts, maize, and cottonseed. These fungi grow best in warm, humid conditions and are particularly prevalent in tropical and subtropical regions. Once the fungi have infected the crops, they produce aflatoxins as a by-product of their metabolism. Aflatoxins are particularly dangerous because they are heat-stable and can survive cooking and other food processing methods.

Aflatoxins are known to be highly toxic to animals, causing a range of adverse effects. The toxins are primarily metabolised by the liver, where they can cause damage to cells and impair liver function. This can lead to reduced appetite, poor growth rates, and weight loss in affected animals. Aflatoxins can also suppress the immune system, making animals more susceptible to infectious diseases.

Aflatoxicosis, the condition resulting from exposure to aflatoxins, can manifest in different ways depending on the species and age of the animal, as well as the level and duration of exposure. In general, signs of aflatoxicosis can include decreased feed intake, decreased weight gain, reduced milk production, and poor reproductive performance. In severe cases, animals may experience diarrhoea, excessive bleeding, jaundice, and even death.

What can farmers do?

Good agricultural practices: Farmers should avoid planting crops in areas with high humidity or moisture and ensure that crops are properly stored and transported.

Proper harvesting: Farmers should harvest their crops at the appropriate time to minimise the risk of fungal infection. They should also ensure that crops are properly dried before storage to prevent moisture buildup.

Quality control: Farmers should implement quality control measures to ensure that their crops are free from fungal contamination. This can include regular testing for aflatoxins and other contaminants, and implementing strict quality control standards for the storage and transportation of crops.

Proper storage: Feeds such as concentrates, hay, silage among others should be stored in a dry place, well-ventilated and devoid of damp conditions. The use of wooden planks below the said feeds to avoid contact with the ground is also very important.

Other prevention strategies include the use of binders, such as clay minerals or activated charcoal, which can bind to aflatoxins and prevent their absorption in the gut.

[The writer is a Veterinary Surgeon]