Mycotoxins: An emerging risk to ruminants
Mycotoxins, in large doses, can be the primary agent causing acute health or production problems in a dairy herd. Feed and crop management is vital to control mycotoxin contamination in feed given to lactating cows, heifers and especially calves.
BY SAMANEH AZARPAJOUH, INDEPENDENT CORRESPONDENT T
he dairy industry is an important part of international economy, and it plays a significant role in providing high quality food for human beings. According to Food and Agriculture Organization of
the United Nations, dairy industry contributes up to 46.8% in the agriculture and milk and dairy products account for about 14% of global agricultural trade. Feed is one of the largest costs in the dairy industry and low- quality feed and naturally occurring toxic contamination in feedstuffs (e.g., mycotoxins) can adversely affect dairy cattle performance and health and causes serious economic issues. The economic impact occurs through the direct market costs associated with lost trade or reduced revenues due to the rejection of contaminated animal products, reduced productivity, death of the animals especially calves which are more sensitive, and increased cost of treatment and mycotoxin mitigation.
What are mycotoxins? Mycotoxins are toxic secondary metabolites produced by fungi and cause mycotoxicosis in exposed animals. Exposure is usually by consumption of contaminated feeds, contact or inhalation. Fungi that can produce mycotoxins grow on numerous feedstuffs such as cereals, dried fruits, nuts, and spices. Fungi growth can occur either before or after harvest, and during storage under warm, damp, and humid conditions. Most mycotoxins are chemically stable and survive food processing. After consuming contaminated feed, animals show a variety of clinical signs. Clinical signs of major mycotoxins in lactating cows, heifers, and calves are summarised in Table 1.
Major mycotoxins Several different mycotoxins have been identified, but the most observed mycotoxins that present a concern to dairy cattle health include aflatoxins, deoxynivalenol, fumonisins, ochratoxin A, zearalenone, T-2 toxin and ergot alkaloids.
▶ MYCOTOXINS | NOVEMBER 2021 7
PHOTO: IMFOTO
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