The word mycotoxin is often talked about in the same way that one would talk about bad news — and it can be for dairy farmers, if not managed properly. Defined as a chemical compound that is produced by a fungus, mycotoxins can be toxic for cells when ingested in high concentration, especially when it comes to dairy cows. This isn’t anything new, though, as we have been dealing with mycotoxins since evolution, said Ohio State extension veterinarian Gustavo Schuenemann in an episode of “The Dairy Podcast Show.” While mycotoxins can be difficult to control, we can do our best to manage them through testing and adjusting inclusion rates in our rations.
While there are over 400 mycotoxin compounds and counting, most begin their journey to the cow when feed is still waiting to be harvested in the field. These chemical compounds also thrive in the cold, especially when being stored away in bunkers, silos, or bags. Whether originating in the field or while in storage, mycotoxins won’t usually kill the cow, but they will cause a reaction. Most reactions happen subclinically for the cow, resulting in abortion, low milk yield, mastitis, low digestibility in the rumen, and effects on the bacteria that produce the vitamin B complex in the rumen. While these can be detrimental to the herd, we can reduce the severity of mycotoxins by dialing in on what is put into the ration.
Mycotoxins begin to cause problems when the rates are very high in the total mixed ration (TMR), and often, you are not only dealing with one but multiple different compounds. Shorter gestation length has been linked to mycotoxin issues and can serve as a tell-tale sign that a problem is evolving. Sampling forages and sending them off to the lab for liquid chromatography testing is highly recommended.
After receiving lab test results, take note of what forages are highly contaminated and make a plan. Mycotoxin levels are often measured in parts per billion (ppb) and can be grouped into three categories: low, medium, and high. While there is usually some contamination in all feeds, 100 ppb is considered low, 300 ppb medium, and 1,000 ppb high. “By knowing the ingredient contamination rate, you can manage the inclusion rate, and through the inclusion rate, you can lower contamination in the TMR,” Schuenemann noted. Other approaches such as the use of binders and buffers were also recommended.
While completely avoiding mycotoxins is nearly impossible for a dairy farmer, there is good news in that if managed correctly, it is possible to lessen their effects. “The number one thing you definitely need to know is what you are feeding the cow in terms of TMR,” Schuenemann said.
