Will Moldy Hay Hurt Sheep If They Eat It?

Rain and other weather can make keeping hay dry difficult.

The result of wet hay is mold growth, most of which is relatively unharmful; the exception being some species of mold that produce mycotoxins which are toxic compounds causing serious illness in livestock and humans.

Most animals will reject the moldy hay as unpalatable, but mold spores are still a concern.

Moldy hay will hurt sheep if they eat it, and the hay contains mycotoxins. It’s impossible to visually tell the difference between normal mold and mold with mycotoxins. If you must feed moldy hay to your sheep, feed it to lower-risk animals, such as mature adult sheep, not pregnant ewes or livestock under stress.

Ruminants, such as sheep, may suffer respiratory issues, lowered fertility, lower food intake, weakened immune systems, and possible death from eating hay with mycotoxins.

Ewes can even have mycotic abortions from eating moldy feed.

For more about moldy hay and feeding your sheep, read on! 

will moldy hay hurt sheep

Can You Feed Moldy Hay To Sheep?

Sheep farmers sometimes know moldy hay has to be used for financial reasons and availability.

The presence of mold in hay is almost a given in some years, although feeding any moldy hay may cause colic or worse.

An average sheep eats 2-3% of their body weight daily and, as a ruminant, needs to be fed consistently.

Further Reading: Guide to how much sheep eat

Growing or nursing sheep need high protein hay such as alfalfa hay with lots of leaves.

Clover hay is also good for high energy needs, whereas timothy orchard grass will suffice for general flock needs and maintenance level sheep.

Sheep getting correct nutrition most of the time will be able to handle consuming moldy hay now and then, but if you are able to get alfalfa pellets instead of moldy hay, do so.

If you must feed moldy hay, here are some tips:

  • Soak the hay in a water trough to reduce the dust; this, unfortunately, leaches out sugars and lowers quality, and may not reduce mycotoxins
  • Steam the hay before feeding, although this has the same marginal effect as soaking
  • Feed in a well-ventilated area to avoid breathing in the spores
  • Discard mold-dense portions
  • Allow animals to choose what they are eating and to pick out the good parts
  • Mix in good hay with the moldy hay to dilute it
  • As a last resort, grinding is an option but can cause the animal to eat more bad hay than they otherwise would, leading to more mycotoxin consumption and health risks
  • Always have an alternative feed source on hand so as not to force your animals to eat moldy hay

Problems With Sheep Eating Moldy Hay

Eating moldy or spoiled feed may cause sheep to get Aspergillosis, caused by the mold Aspergillus fumigatus.

Aspergillosis is mainly a respiratory disease because the Aspergillus is breathed in, but it can cause mastitis and systemic infection in sheep.

Generalized Aspergillosis also causes problems in the lymph nodes, kidneys, lungs, liver, heart, forestomachs, and brain of affected sheep.

Listeriosis, caused by the bacterium Listeria, is commonly caused by eating moldy or spoiled feed or silage.

The symptoms of Listeriosis are: 

  • Depression
  • Loss of appetite
  • Fever
  • Lack of coordination
  • Salivation
  • Facial paralysis
  • Circling

Listeria bacteria are in the soil, food sources, and even the poop of healthy animals, so it is a difficult bacterium to avoid.

Livestock producers must carefully monitor their animals for reproductive health, efficient feed utilization, and overall health indicators such as coat, body weight, and alertness.

Other molds found in hay include Alternaria, Cladosporium, Fusarium, Mucor, Penicillium, and Rhizopus.

Breathing in the spores of these molds causes respiratory problems in animals and humans.

Under some conditions, these molds will produce mycotoxins.

To read more about livestock problems caused by moldy hay and testing for mold, read what Pennsylvania State Extension has to say. 

How to Prevent Moldy Hay For Your Sheep

While we all know mold is bad at this point, there are some things we can do to prevent the mold in the first place. 

Let’s be clear, though: it’s impossible to completely prevent hay from going bad. 

When you find mold, it’s best not to risk feeding it to your sheep. 

Just do something else with it! (More on this in the next section.) 

But there are some quick tips to consider to keep your hay as fresh as possible and not lose money or risk harming your livestock. 

Put the bottom layer of bales on their sides. 

If you have hay still baled up, putting it on its sides (strings facing sideways) is a great way to limit the amount of mold getting in. 

The sideways position allows for more air to get in and between the fibers. 

Good circulation prevents mold and keeps everything drier. 

Stack the upper layers in an interlocking pattern. 

Make the second layer perpendicular to the bottom and alternate the stack, like you would with Lincoln Logs or Lego. 

This will keep the stack more secure and prevent falling. 

Once the hay is on the ground, there’s a much higher chance of mold. 

Leave space between the bales. 

Where possible, give the bales some breathing room. 

An inch or two of space is more than enough to prevent the bulk of mold infestations. 

Keep away from walls and ceilings. 

If airflow and dryness are key, keeping everything away from walls and ceilings makes sense. 

Putting them too close causes two main problems: 

  1. You prevent airflow and encourage mold growth. 
  2. Some walls and ceilings may condensate and allow water to gather in the hay. 

Both are good for mold and bad for your hay and sheep. 

What Can I Do with Moldy Hay?

Moldy hay makes a good mulch for your garden.

Use moldy hay to plant potatoes, adding to the height as you go.

Hay bales make terrific planters if they are still bound up. 

Hay bales also make great insulators for compost, holding in moisture and keeping the temperature nice and hot. 

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Growing up amidst the sprawling farms of the South, Wesley developed a profound connection with farm animals from a young age. His childhood experiences instilled in him a deep respect for sustainable and humane farming practices. Today, through Farmpertise.com, Wesley shares his rich knowledge, aiming to inspire and educate others about the joys and intricacies of rural life.

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