Published 11 December 13

Key messages

  • Penicillium and Aspergillus derived mycotoxins are often associated with the storage of feedstuffs and ensiled forages.
  • Penicillium based mycotoxins in particular, can affect the sensory quality and palatability of forages, leading to a reduction in feed intakes.
  • Effects of mycotoxin poisoning are often diverse and hard to isolate from other issues
  • Test your forages and any home-grown cereals for mycotoxins – testing has become much cheaper at <£10 per sample.
  • Introducing rumen buffers, mycotoxins absorbers or particle binders may help alleviate the problem.

 

Mycotoxins

Good harvesting conditions this year have led to high quality forages being produced for this winter (see Silage Update in 15 November edition of FfK). Although the risk is somewhat reduced by good fermentation, mycotoxins caused by mould growth and poor silage management, can still pose a threat to cow production. Here’s what you need to know about mycotoxins.

Mycotoxins: the basics

Mycotoxins are toxic compounds which are produced naturally from fungal species or moulds. One mould is capable of producing several mycotoxins, and one mycotoxin may be produced by several different moulds. However, the majority of mycotoxins are derived from three main mould groups: Fusarium, Aspergillus and Penicillium.

 Penicillium and Aspergillus derived mycotoxins are often associated with the storage of feedstuffs and ensiled forages. Penicillium based mycotoxins in particular, can affect the sensory quality and palatability of forages, which can lead leading to a reduction in feed intakes.

As mycotoxins are very stable compounds that ‘survive’ on the crop/grain long after the initial mould has disappeared, the absence of mould does not necessarily mean the crop is ‘clean’ (the reverse situation also applies). Although routine testing is carried out for mycotoxins, such as DON, producers utilising home-grown grain and conserved forage to feed animals on farm may be at increased risk of introducing a mycotoxin challenge to their animals.

Symptoms of mycotoxicosis

With around 500 different types of mycotoxins, the effects of mycotoxin poisoning are often diverse and hard to isolate from other issues. Fusarium derived mycotoxins, such as zearalenone, have been linked to animal fertility reducing embryo survival, decreasing conception rate and causing abortions. Likewise deoxynivalenol, another common Fusarium mycotoxin has been associated with reductions in milk production.

Ruminants are less susceptible to many mycotoxins compared with non-ruminants due to the ability of the rumen microbes to degrade them to less harmful compounds. However, if this ability becomes impaired by an antibiotic action, then the animal becomes increasingly susceptible to those mycotoxins. To this end, Penicillium mycotoxins are receiving increased attention.

Penicillium mycotoxins are described as ‘silage’ mycotoxins due to their presence in conserved forage (including silage, haylage and hay) and there are many factors that contribute to the level of contamination. As Penicillium is a storage mould, ‘stressors’ during harvesting and ensiling lead to proliferation of associated mycotoxins. Contamination avoidance is virtually impossible but following good silage management practices such as keeping a clean silage face and minimising mould growth can go a long way to minimising the risk to livestock.

If you suspect that mycotoxins may be a problem on your farm it is advisable to test your forages and any home-grown cereals for mycotoxins. New technology has meant testing for mycotoxins has become much cheaper (<£10 per sample). More information on testing can be found on the HGCA website at http://www.hgca.com/publications/documents/cropresearch/FusariumGuide-Testing.pdf.

If you have identified high levels of mycotoxins on your farm, introducing rumen buffers, mycotoxins absorbers or particle binders may help alleviate this problem.