By Dr Hsueh lui Ho, Volac’s Global Technical Manager for Feed Additives
It can be easy to associate mycotoxin risk with housed diets, but background levels in grazed grass and concentrates mean they need to be on dairy farmers’ radars all year round.
Mycotoxins are produced by certain moulds which can grow on bought-in feeds and forage. These mycotoxins have wide-ranging effects including reduced feed efficiency, suboptimal yields, poor fertility and lameness.
Moulds grow everywhere, even on fresh grass, and don’t have to be visible to be a problem. Mycotoxins that aren’t traditionally considered storage mycotoxins (such as DON) can still be found in grass silage samples, so it’s likely they were there at point of harvest. Fresh grass may be low risk, but it is still a risk.
Conserved forages, and parlour concentrates too, are a potential source of toxins, particularly if they include high-risk ingredients such as distillers’ grains or maize components. Results from 776 UK & Ireland feed and forage samples tested through Volac’s Mycocheck service in 2025 found that mycotoxins were present in 100% of concentrates, 99% of maize silage samples and 80% of grass silage samples.
Low background levels of mycotoxins can cause cows to perform below their full potential, likely leading to suboptimal yields. An animal “in balance” with no stressors should be able to cope reasonably with mycotoxins, depending on the exact challenge, but any additional stressor can tip this delicate balance, impacting productivity, health or fertility.
Stress can be caused by multiple things, such as high temperature and humidity or turnout following winter housing. With that in mind, it’s important to take a preventative approach towards mycotoxins and incorporate a mycotoxin remediator into the diet.
Ultrasorb - a triple-action mycotoxin remediator and endotoxin binder - binds, transforms and degrades a wide range of mycotoxins using a combination of specifically selected clay binders, yeast fractions and biological active agents. It is available through Trident MicroNutri in the UK and can be incorporated into the diet in multiple ways including in blends, parlour cake or minerals.
Feeding it at a preventative rate of 10g per cow per day will help keep the herd equilibrium and protect against any spike in mycotoxins or sudden stressors that could depress herd health and performance.