Mycotoxin Reflections

December 15, 2016

John A. Doerr, PhD

Getting ready for your new crop corn silage?  Some time ago interaction of aflatoxin (AF) and ochratoxin A (OA) was studied in chickens. AF birds had big livers were pale to yellow, with fatty inclusions.  OA birds had enlarged kidneys and livers.  Livers from AF+OA birds looked normal!  Kidneys were huge. If those organs were evaluated by a veterinarian, the normal colored liver would be the basis to discount aflatoxin and the excessive size of the kidneys would suggest something more insidious than the amount of ochratoxin in the feed.  This is a stunning example of a mycotoxin-mycotoxin synergistic interaction.  Fundamentally, putting two mycotoxins together yielded a new syndrome or disease, differing markedly in what one typically expects from either of these two mycotoxins.

Now, you might think you understand DON in the dairy cow.  You might have a handle on zearalenone in the Holstein you are trying to breed.  But what will you predict will happen when these two mycotoxins are combined with emodin, fusaric acid, mycophenolic acid and perhaps 5-25 others in the ration? (You aren’t going to test for these [have you heard of them?!] because they aren’t included in most commercial tests, but they do occur regularly in dairy rations!)  The combination of multiple mechanisms of action, sites of damage, etc. can produce effects both unexpected and unrecognizable as ‘typical’ mycotoxin issues.  This is consistent problem with feedborne mycotoxins…they can and do interact.

I’d love to stop there, but interaction is not confined to just mycotoxin on mycotoxin.  These fungal poisons interact with stressors, such as heat, cold, social stress, oxidative stress, etc.  They interact with disease agents, viral, bacterial, or parasitic.  And in many cases the outcome will be a mis-diagnosis which points the blame at an infectious agent or management or other, when the real initiator and potentiator of the problem are multiple mold toxins in the feed.  

So, what do you intend to do? Hope for the best? Use a binder with a single toxin high affinity capability and hope you plucked out the right toxin? Or do you think it is rather important to have a sound, continuous strategy for coping with mycotoxins on your dairy farm? In the face of multiple mycotoxin exposure, you may find the most economical and effective solution is a biological approach that enhances a natural defense mechanism in the cow. Please contact your local Select Sires representative to discuss your situation and the options that are available. http://agrariansolutions.com/d...