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Moldy hay

Act quickly: how to properly identify and deal with moldy hay

 Verschimmeltes Heu

How to recognize moldy hay

Typical warning signs of moldy hay are:

  • Dust clouds when shaking (noticeably strong, not just "normal hay dust")
  • Musty, sweetish-moldy or "cellar-like" smell
  • White, grey or black coatings / “threads” / pinpoint nests
  • Moist, warm areas of the bale (heat can indicate secondary fermentation and microbial activity)
  • Crumbly, brittle, discolored hay or visible "hotspots" in the bale

Important: Mold is not always immediately visible. Often the problem is located inside the bale.

Applications

You can also reduce mold growth in hay by storing it correctly. Choose a dry, well-ventilated storage area to prevent moisture buildup and mold formation. It's best to store hay in smaller quantities and rotate your hay regularly to avoid long periods of inactivity.

By choosing AnoKath® heuSan to support hay hygiene, you are opting for reliable, high-quality products. This allows you to seamlessly integrate the application into your daily feeding routine, keeping your hay more stable and easier to handle overall.
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Properly handling moldy hay: identifying, sorting out, safely disposing of – and targeted treatment of less affected hay.

Moldy hay isn't just a minor flaw; it's a serious hygiene and health risk. Otherwise, you're unnecessarily exposing your horses to mold spores, yeast, and other microbial contaminants. These substances irritate their respiratory system, impair feed intake, and noticeably degrade the stable's climate. Therefore, take decisive action: consistently dispose of inedible, heavily infested hay. Treat less affected hay – following the application instructions – with heuSan to reduce the hygienic burden and improve handling.

Why heavily moldy hay must be disposed of.

If the hay smells distinctly musty, shows visible mold, or is very dusty when moved, the rule is: Do not feed it to your animals. Do not mix it in. Do not try to sugarcoat it. Classify it as inedible and dispose of it properly. Otherwise, you will unnecessarily expose animals – and also people in the stable – to spores, especially those with sensitive or compromised respiratory systems.

Rule of thumb: If you immediately get a bad feeling about the smell, dust, or coating of a bale when you open it, sort it out and dispose of it. That way, you make the safe decision.

Step-by-step: How to properly deal with moldy hay

1) Separate the bales immediately

Do not distribute suspicious bales further in the hayloft

Store separately to prevent spores from unnecessarily spreading throughout the entire stock.

2) Visual inspection + “hotspot” check

Open the bale and check inside

Mark conspicuous areas generously or discard them immediately.

3) Dispose of heavily infested batches consistently.

Completely remove areas with visible mold, strong mustiness, or damp clumps.

In case of widespread or deep-seated infestation: dispose of the entire bale.

4) Consider stable hygiene

Thoroughly clean shaking areas, hay boxes, and hayrack areas.

Minimize dust generation as much as possible (e.g., open outdoors, pay attention to wind direction)

Treat less infested hay: Support with haySan

Not every hay with unusual signs of infestation is automatically a "total loss". If you only notice a slight, localized infestation (e.g., individual small areas without a strong musty smell and without massive dust clouds), a clear course of action is worthwhile: You consistently sort out the affected parts and then treat the remaining hay additionally.

You use heuSan to reduce hygienic contamination and improve handling in the stable – always according to the label and instructions for use. You don't want to magically "make good" bad hay with it. You're simply ensuring hygienic safety in borderline cases after removing any clearly inedible parts.

Practical tip: Only treat hay that remains visually and olfactorily acceptable after sorting. If the bale appears "bad" overall (consistently musty or very dusty), treatment does not replace disposal.

Common causes of mold in hay – how to prevent it from happening again

  • Excessive residual moisture during pressing
  • Dense storage without ventilation
  • Condensation/temperature fluctuations in the warehouse
  • Bales are standing on damp ground or too close to walls
  • Prolonged storage in unfavorable climates

Prevention that has proven effective in practice:

  • Store hay in a dry, airy place, away from the ground (pallets).
  • Do not stack bales "too tightly" – allow for air circulation.
  • Check suspicious batches early (smell/indoors)

FAQs

Moldy hay

What to do about moldy hay?

Immediately separate the bale from the rest of the crop and open it for an internal inspection. Generously remove and discard any heavily infested, damp, or musty sections. If the infestation is minor and localized, treat the remaining portion with AnoKath® heuSan according to the application instructions after sorting to reduce the hygienic burden.

Is it enough to remove moldy parts of the hay – and can the rest of the bale be fed to the animals?

Only remove moldy areas if the rest of the hay appears dry, smells neutral, and doesn't produce noticeable dust clouds. If musty odors, multiple patches of mold, or damp clumps remain, discard the entire bale. In minor borderline cases, AnoKath® heuSan supports hay hygiene after sorting – it does not replace disposal.

How can I recognize mold in hay?

Look out for a musty, moldy smell, visible deposits or nests, discoloration, damp, warm areas, and unusually heavy dust when shaking the hay. Always check the inside of the bale as well, since mold is often hidden within. If you have any doubts, immediately and consistently separate the affected batch and only feed hay that appears healthy.

If the hay is dusty: Is that automatically mold?

Dust alone doesn't automatically mean mold; sometimes it's just dirt or crumbly hay that gets stirred up. However, if you combine dust with a musty smell, damp clumps, or internal deposits, mold is likely. In that case, separate the bale, check the inside, and discard it if there's significant infestation. For light infestations, AnoKath® heuSan provides support after sorting.

Hay disposal: What to do with moldy hay?

Dispose of moldy hay in a way that prevents the spread of spores in the barn: store it separately for a short time and transport it covered. Your local council determines where you can dispose of it – often a recycling center, green waste collection point, or an agricultural waste disposal company can help. It's best to check beforehand rather than letting it sit around for too long.

How do I prevent mold growth in hay?

Store hay on pallets in a dry, well-ventilated place, away from the ground. Allow air to circulate between the bales, maintain a distance from walls, and prevent condensation by ensuring stable temperatures. Check new batches early by smell and internal inspection, and immediately separate any suspicious bales. For borderline cases after sorting, AnoKath® heuSan supports daily hay hygiene.