Is Net-Wrapped Hay Safe for Horses? (Net Wrap vs. Baleage)

By the XES Netting team — bale net-wrap manufacturer · Updated August 16, 2026 · ~26 min read

This page cannot clear your hay. There is no appearance test, no smell test and no single laboratory number that establishes a bale is safe for horses — the evidence for that is set out below. Everything below is sourced to veterinary bodies and land-grant Extension, with the source named at each point — and where a commonly repeated figure could not be verified, it is left out and said so. Feeding decisions for a specific horse belong to your veterinarian or a qualified equine nutritionist. This page is general information and is not veterinary, nutritional or agronomic advice.

Who wrote this, and what we sell. XES Netting manufactures bale net wrap. That is a reason to be sceptical of us on this particular question, so we have written it the other way round: this page argues that the wrapper is not the thing that makes hay safe, carries no product recommendation and no call to action, and points every real decision at your veterinarian, your forage laboratory and the equipment manuals. We are not veterinarians or equine nutritionists.

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The wrapper is not the question

"Is net-wrapped hay safe for horses?" is asked as though the mesh were the variable. It is not. Net wrap is a binding that holds a bale in shape during handling and storage. It is the same forage inside whether it was tied with sisal twine, plastic twine or net.

The useful version of the question is: is this hay sound, and is it right for this horse? Those are answered by the crop and its history — species and maturity, what else was growing in the field, moisture at baling, whether it heated, how it was stored, what was applied to it, and what a laboratory says about the lot. None of that is visible from the outside of a bale, and none of it is determined by the wrapper.

So this page is organised around the forage. The wrapper gets one section, because there is exactly one rule about it, and it is not optional.

Open mesh and oxygen-barrier film are different things

Two products get called "wrapped", and confusing them is the single most common error in this topic.

Net wrap is not a substitute for film and film is not net wrap. A bale in mesh has not been preserved by its wrapper; a bale in film has. If you are not certain which you are looking at, ask the producer what moisture it was baled at and whether it was wrapped to ferment — and get the answer before it is fed.

Layer counts, film specifications and wrapping intervals differ by machine, film and system, so the numbers that apply to a given bale are the ones in that product's label and that wrapper's manual. We are not publishing a universal layer count or moisture table here, because there isn't one.

All binding comes off, and how to do it safely

This is the one rule that genuinely is about the wrapper, and it applies to net, plastic twine and sisal alike.

Plastic mesh and plastic twine are not feed. They do not break down usefully in the digestive tract. A horse pulling hay from a bale that still has binding on it, or picking at scraps on the ground, can ingest plastic or become entangled in it — with choke, foreign-body and colic risks that are entirely preventable by removing it. There is no published safe ingested quantity for horses, and the sensible target is none.

• Remove every piece before horses have access, and account for what you removed — net that has torn into strips is easy to leave behind.
• Pick up scraps off the ground, including around feeders where shed mesh collects.
• Never feed, unroll, grind or process a bale with binding still on it. Processing does not neutralise plastic; it distributes it.

Removing wrap is a machinery task, not a casual one. Follow the exact instructions in your loader, feeder or processor manual. Before anyone approaches a bale to cut or pull binding: lower the bale fully and make sure it is supported and stable, set the park brake, shut the machine down and remove the key, and stand outside any path the bale could roll or fall into. Never cut binding from a raised or suspended bale, and never work under one. A large bale that moves unexpectedly does not give you time to react.

Botulism: what AAEP actually says

Botulism comes up constantly in this conversation, usually attached to the wrong variable. Here is the American Association of Equine Practitioners in its own words, on the three ways horses get it:

"Wound botulism results from germination of spores of serotype B and subsequent production of toxin in contaminated wounds.

Shaker Foal Syndrome (toxicoinfectious) results from toxin produced by germination of ingested spores in the intestinal tract…

Forage poisoning results from ingestion of preformed toxin produced in decaying plant material, including improperly preserved hay or haylage, or silage. Commonly animal carcass remnants present in feed are the cause." AAEP botulism vaccination guidelines.

Read that carefully, because two things follow.

First, AAEP does not frame this by packaging at all. Net wrap, twine and film are not mentioned. The risk is described in terms of decaying plant material and carcass remnants in feed — which means a dry, net-wrapped bale is not exempt by virtue of being dry or being in mesh. A rabbit, bird or rodent baled into dry hay is a carcass in feed. Spoiled material inside a weathered bale is decaying plant material.

Second, "improperly preserved hay" is named alongside haylage and silage. The old shorthand that botulism is a baleage problem and dry hay is exempt does not survive contact with the source.

There is no bale-side safety test. Ontario's provincial agriculture guidance on botulism in horses and haylage puts the point in evidence rather than assertion: "Several incidents of botulism occur each year after horses eat wrapped or bagged round bale haylage. In some of these outbreaks, the haylage looked and smelled spoiled. In others, the bales didn't look as if they were spoiled but horses eating them developed botulism." So a bale that looks and smells fine is not thereby cleared. Nor does a single pH reading clear it — pH, moisture, fermentation quality and package integrity describe how a preservation process went, not whether toxin is present. The same Ontario page notes that it is rarely possible to detect the toxin in suspect feed at all, and that "a negative test does not mean that an animal is not affected by the disease." Treat "it looked and smelled all right" as what it is: not evidence. (That evidence is drawn from haylage incidents; it is cited here for the general principle that sensory inspection is not clearance, not as a claim about dry hay specifically.)

On the organism itself, AAEP's vaccination guidance notes that "serotypes A, B and C are associated with most outbreaks of botulism in horses." Its separate botulism disease page adds the detail: type A is prevalent in soil in the western US; type B spores are typically found in soil east of the Mississippi, particularly the Northeast and Appalachian regions and Kentucky, and type B is "responsible for greater than 85% of cases"; and type C "is found in carrion". Ontario's provincial agriculture guidance makes the same association plainly, describing type C as "carrion botulism because of the association with the ingestion of feed containing a decomposing carcass (for example, rodent, cat, dog, bird)."

The botulism vaccine, accurately

"Just vaccinate" is common advice and it is not what the guidance says. AAEP:

• It is a risk-based vaccine, not a core one. "Vaccination against botulism is currently not a core vaccine in horses. Vaccination is a risk-based decision for horses at increased risk… due to residence in (or travel to) endemic regions", with adult horses fed high-risk forages and foals of unvaccinated mares named as particularly susceptible groups within those regions.
• Only type B is licensed, and there is no cross-protection. "A killed vaccine (toxoid) directed against Cl. botulinum serotype B is licensed for use in horses in the United States… Currently, no licensed vaccines are available for preventing botulism due to serotypes A or C or other serotypes of toxins. Cross-protection between subtypes does not occur." A vaccinated horse is not protected against type A or type C.
• The adult series is three doses. "Unvaccinated adult horses: Vaccinate with 3 doses at 4-week intervals." "Previously vaccinated adult horses: Revaccinate annually."
• Pregnant mares and foals have their own schedules. Previously vaccinated mares are revaccinated annually with a single dose 2 to 4 weeks before foaling; previously unvaccinated mares receive 3 doses at 4-week intervals timed so the last falls 2 to 4 weeks before foaling. High-risk foals "may have the vaccination series initiated as early as 2 weeks of age."
• It is a veterinary decision. AAEP frames botulism vaccination as risk-based rather than routine, keyed to region and to what the horse is fed — which makes it a conversation with your own veterinarian, not something to settle from a webpage. (AAEP's botulism vaccination guidance carries the note "Reviewed and revised 2019", so check with your vet for anything more recent.)

So: whether to vaccinate, when, and what it does and does not cover are questions for your veterinarian, informed by where you are and what you feed. Vaccination is not a licence to feed questionable forage, and it is not protection against every serotype.

What actually determines whether dry hay is sound

Not the wrapper. These are the variables that decide it.

Moisture at baling — and it depends on the package

Purdue Extension gives target moisture to begin baling without an effective preservative as 20% for small rectangular bales, 18% for large round bales and 17% for large rectangular bales. Denser and larger packages tolerate less. Preservatives change the picture, and the product label controls how they are used.

NDSU Extension puts the fire threshold at "20 percent or higher in small stacked bales and more than 18 percent in stacked large square or round bales." UConn Extension, writing specifically about equine botulism prevention, advises making "sure hay is baled at less than 22% moisture level or use acid preservatives on hay when baling."

Do not read UConn's 22% as a target for large round bales. It is a general upper bound in a botulism-prevention context, and it does not override the package-specific figures: Purdue's target for large round bales without an effective preservative is 18%, and NDSU treats more than 18% in stacked large square or round bales as a fire hazard. Where these differ, use the lower, package-specific number for your package.

Measure it, do not estimate it, and measure representatively rather than from one convenient bale.

Heating, and the six weeks after baling

NDSU: "Hay fires usually occur within six weeks of baling." Purdue adds that a temperature rise after baling is normal but "anything greater than 125 degrees F should be intently monitored", and that with storage-structure fires "it may take three to four weeks before spontaneous combustion occurs", so a few days of readings prove nothing. NDSU also notes that "if you detect a slight caramel odor or distinct musty smell, your hay likely is heating", and to call the fire department immediately above 175°F.

Hay that heated is not just a fire question — it is a feed-quality and mould question, and it is one of the histories worth asking a seller about.

Storage and weathering

UConn's equine guidance is direct: "Do not allow any round bales to be exposed to the weather. Check round bales periodically for quality. Spoiled material is most likely to be internal in round bales and may need to be opened to check for quality." That last point matters — the outside of a bale is not a reliable report on the inside.

Mould, dust and equine airways

Penn State Extension is unambiguous: "If hay is moldy, do not feed it." It lists Alternaria, Aspergillus, Cladosporium, Fusarium, Mucor, Penicillium and Rhizopus among the moulds commonly found in hay, noting these "can produce spores that cause respiratory problems, especially in horses and, under some conditions, will produce mycotoxins." University of Minnesota Extension agrees: "Don't feed horses moldy hay… Excessive mold may cause coughing, heaves or allergic reactions if horses inhale it."

Penn State describes the airway disease at stake — a condition it calls Recurrent Airway Obstruction or heaves, now more usually discussed under the heading of equine asthma — in which an affected horse has "a normal temperature and a good appetite, but will often have decreased exercise tolerance, coughing, and nasal discharge."

Soaking and steaming are dust management, not decontamination. Penn State: "Soak dusty hay for 5 to 30 minutes before feeding. This will help minimize respiratory problems associated with dust and mold spores, but will not reduce the threat of mycotoxin contamination." UMN's steaming work found steaming "reduced mold content in both hays by about 90 percent" but concludes that "neither soaking or steaming should replace the main goal of feeding hay with low mold and dust content." If a horse needs soaked or steamed hay, that is a management plan to make with your veterinarian — not a way to rescue a bad lot.

Toxic plants, beetles and foreign objects

This is where "judge the forage, not the wrapper" earns its keep, because none of the following is visible from outside a bale and none of it is affected by how the bale was tied.

Curing can make a dangerous plant easier to eat. Oregon State University Extension: "Never include poisonous plants in hay. Drying may improve palatability and animals fed only small amounts of hay may be hungry enough to eat the weeds." A horse that walks past a plant in a pasture may eat it out of a bale.

Hoary alyssum is a horse-specific example worth knowing. UMN Extension: "Don't feed hay containing hoary alyssum to horses… Most hoary alyssum poisoning occurs when horses eat infested hay." It reports that about half of horses eating it show signs including limb swelling, fever of 103°F or higher, warm hooves, pronounced digital pulse and stiff joints, usually 12 to 24 hours after ingestion, and rarely death.

Blister beetles in alfalfa are the clearest illustration that storage does not fix contamination. UMN Extension: cantharidin is "released when the beetle is crushed during hay making", and "cantharidin remains toxic in dead beetles and the level of toxin does not decrease during hay storage."

Carcasses. UConn's equine botulism guidance: "Check your bales of hay and feed carefully to be sure that there are no small, dead animals included, since ingesting the bacterium in feed is the most common route of infection." This is the same hazard AAEP names, and it is a field-and-mowing question, not a packaging one.

Also worth checking for: wire, netting, plastic and other foreign material picked up by the baler, and soil or ash contamination from a low cut.

Pesticide history

Ask what was applied to the field, get it in writing, and read the current product label — the label controls harvest intervals, whether the forage may be fed, and what may be done with the manure. Some pasture and hayfield herbicides carry restrictions that follow the hay and the manure well beyond the field, and product names and formulations change, so a list in an article is a prompt to check the label rather than a substitute for it. If you cannot get a straight answer about what was sprayed, that is itself information.

Test the lot

Sampling is what turns a guess into a number, and it has to be representative. Penn State Extension: "Always sample with a bale corer… It is impossible to get a representative sample using bale slices." Take cores from each field and cutting separately — Penn State advises sampling at least 10 large bales or 20 small bales per lot, coring large round bales "toward the center of the bale from the curved edge", then mixing the cores and sending a composite.

What to ask the laboratory for depends on the horse. A basic panel — dry matter, crude protein, fibre fractions and an energy estimate, plus calcium and phosphorus — describes the forage. Where a horse has a metabolic condition, sugar and starch analysis matters, and there are additional tests worth running where a specific concern exists. Which tests, and what the results mean for a particular animal, is a conversation with your veterinarian or a qualified equine nutritionist, taking into account age, workload, pregnancy or lactation, metabolic and respiratory status, dental condition, and the rest of the ration. A hay analysis does not, by itself, say "safe" or "suitable".

Round bales and horses

Round bales are a management format, not a hazard in themselves, but they change how horses interact with the forage.

Use a feeder designed for horses. UMN Extension's comparison found "using a feeder resulted in less hay waste (5 to 33 percent) than not using a feeder (57 percent)", and that "feeders that restrict the horse's access to hay cause less hay waste (5 to 11 percent) than feeders that provide greater access (13 to 33 percent)." It also reports that herds without a feeder "had an average weight loss of 225 pounds for the herd", likely because of greater spoilage. On safety it notes "horse injuries were uncommon when using the tested feeders", with cosmetic rub marks possible on some designs — and a specific caution that with hay nets "the round bale can collapse, and horses may be able to stand and pass manure or urine on the remaining hay."

Those percentages come from that comparison and the Texas work it cites; they are figures from specific studies with specific feeders and hays, not a guarantee for your setup.

Site it well and keep the interval short. Put the feeder on clean, well-drained ground. On how long a bale should last, UConn advises: "If you do feed round bales, it is best to have an amount that horses can consume in one week to avoid having them consume moldy feed." That is UConn's recommendation in the context of botulism prevention, not a universal rule — the right interval for you depends on group size, weather, feeder design and how the bale is holding up, and a bale that deteriorates faster than that should come out sooner.

Baleage and haylage are a different product

Fermented wrapped forage is a genuinely different thing from dry hay, and it is fed to horses in some places. It is also outside what this page can responsibly specify, for two reasons: the controls are system-specific, and the horse-feeding practice varies.

What can be said from a current Extension source, with its scope attached: University of Georgia Extension's baleage FAQ — a general livestock production guide, not a horse-feeding document — states that "baleage can be made between 40% and 60% moisture, but fermentation is best when whole plant moisture is 50% to 60%", that forage below 40% or above 65% moisture "should not be baled for silage to avoid excessive molding or spoilage", and that "baling above 65% moisture increases the chance of undesirable butyric acid fermentation by Clostridia bacteria." On botulism specifically it says the risk "is minimized by baling at less than 60% moisture, using at least four layers of plastic, and preventing puncture damage to plastic during storage" — note minimized, not eliminated.

What we could not verify, and are therefore not publishing. Commonly circulated figures for horse baleage — a specific transition period when introducing it, and a specific number of hours in which an opened bale must be fed out — could not be confirmed in the UGA sources reviewed here. They may well appear in other current publications we did not read. Rather than attach numbers to the wrong source, we are naming the gap: get the moisture specification, wrapping specification, storage handling and feed-out window from the producer and from a horse-specific source, and confirm the plan with your veterinarian before feeding fermented forage to horses.

Two things do carry across regardless: absence of a bad smell or visible mould is not proof that a fermented bale is sound, and package integrity matters — a tear or puncture admits oxygen and changes what is going on inside.

If you sell hay to horse owners

Horse buyers are asking a harder question than "what is it tied with", and the sale goes better when the answer is already written down. Disclose:

• Lot and field identity, species or mix, and cutting.
• Harvest date.
• Moisture at baling, how it was measured, and whether a preservative was used — and which.
• Storage — inside or out, on what surface, covered or not, how long, and any known heating.
• Pesticide history, in writing, with any label restrictions that follow the hay or the manure.
• Known concerns — weather damage, mould, dust, toxic weeds identified in the field, or foreign objects.
• Representative analysis for the lot being sold, with the sampling date and the basis it is reported on.
• Bale dimensions and a representative measured weight, with the moisture at which it was weighed.
• Price unit and basis, and delivery and unloading terms.

Disclosing is not warranting. Do not guarantee that a lot is suitable for any particular horse — suitability depends on the animal, and that judgement belongs to the buyer's veterinarian or equine nutritionist.

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The bottom line

Net wrap is packaging. It comes off completely before a horse can reach it, every time, and that is the whole of its safety story. What it is not is evidence about the hay.

The evidence about the hay comes from somewhere else: what was growing in the field, whether anything was baled in with it, moisture at baling and whether the bale heated, how it was stored, what was sprayed, what the laboratory says about the lot, and what your veterinarian or equine nutritionist makes of all that for the particular horse. AAEP's own description of forage botulism names improperly preserved hay and carcass remnants — not a type of wrapper — and that is the right way round to think about it.

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Frequently asked questions

Is net-wrapped hay safe for horses?

Net wrap is packaging, and it does not establish whether the hay is safe. Two things follow. All binding must be removed before horses have access, because plastic mesh is not feed and can be ingested or become an entanglement, choke or foreign-body hazard. And the forage itself has to be judged on its own history, because a dry, net-wrapped bale can still be mouldy or dusty, contain toxic plants, insects or a carcass, carry pesticide restrictions, or simply be unsuitable for a particular horse. What determines safety is how the crop was grown, cut, cured, baled, stored and tested, and what your veterinarian or a qualified equine nutritionist advises for the horse in front of you.

Can horses get botulism from dry hay?

Dry hay is not exempt. The American Association of Equine Practitioners describes forage poisoning as resulting from ingestion of preformed toxin produced in decaying plant material, including improperly preserved hay or haylage or silage, and adds that animal carcass remnants present in feed are commonly the cause. AAEP does not distinguish risk by packaging at all — net wrap, twine and stretch film are not mentioned in its botulism guidance. A carcass baled into dry hay is a carcass in feed, and spoiled material inside a weathered bale is decaying plant material. There is also no bale-side test. Ontario provincial agriculture guidance reports that after horses ate wrapped or bagged round bale haylage, in some outbreaks the haylage looked and smelled spoiled while in others the bales did not look spoiled and horses eating them still developed botulism, so sensory inspection is not clearance. That evidence comes from haylage incidents and is cited for the general principle about the limits of sensory inspection rather than as a claim about dry hay specifically. Nor does a single pH reading clear a bale, because pH and moisture describe how a preservation process went rather than whether toxin is present.

Should I vaccinate my horse against botulism?

That is a decision for your veterinarian, and the guidance is more specific than a simple yes. AAEP states that botulism vaccination is currently not a core vaccine in horses and is a risk-based decision for horses at increased risk due to residence in or travel to endemic regions, with adult horses fed high-risk forages and foals of unvaccinated mares named as particularly susceptible groups within those regions. The licensed product is a killed toxoid directed against serotype B only. AAEP states that no licensed vaccines are available for serotypes A or C and that cross-protection between subtypes does not occur, so a vaccinated horse is not protected against every serotype. For unvaccinated adult horses the series is 3 doses at 4-week intervals, with annual revaccination thereafter, and pregnant mares and foals have their own schedules. AAEP frames botulism vaccination as risk-based by region and by what the horse is fed rather than as routine, so the decision belongs with the horse's veterinarian, and AAEP's botulism vaccination guidance carries a reviewed and revised 2019 note. Vaccination is also not a reason to feed questionable forage.

Can horses eat net wrap?

No, and the aim should be that none is ever available to them. Plastic mesh and plastic twine are not feed and do not break down usefully in the digestive tract, so ingestion or entanglement brings choke, foreign-body and colic risks. Remove every piece before horses have access, account for what you removed because torn net is easy to leave behind, and pick scraps up off the ground including around feeders where shed mesh collects. Never feed, unroll, grind or process a bale with binding still on it, because processing does not neutralise plastic, it distributes it.

How do I remove net wrap safely?

Follow the exact instructions in your loader, feeder or processor manual, because the safe method depends on the machine. Before anyone approaches a bale to cut or pull binding, lower the bale fully and make sure it is supported and stable, set the park brake, shut the machine down and remove the key, and stand outside any path the bale could roll or fall into. Never cut binding from a raised or suspended bale and never work underneath one. A large bale that shifts unexpectedly does not leave time to react.

What moisture should horse hay be baled at?

It depends on the package and on whether a preservative is used, and it should be measured rather than estimated. Purdue Extension gives target moisture to begin baling without an effective preservative as 20 percent for small rectangular bales, 18 percent for large round bales and 17 percent for large rectangular bales. NDSU Extension puts the fire hazard threshold at 20 percent or higher in small stacked bales and more than 18 percent in stacked large square or round bales, and notes hay fires usually occur within six weeks of baling. UConn Extension, writing on equine botulism prevention, advises making sure hay is baled at less than 22 percent moisture or using acid preservatives when baling. Do not read that 22 percent as a target for large round bales: it is a general upper bound, and it does not override the package-specific figures, since Purdue's target for large round bales without an effective preservative is 18 percent and NDSU treats more than 18 percent in stacked large square or round bales as a fire hazard. Where the numbers differ, use the lower package-specific one for your package. Monitor for heating after baling as well: Purdue advises that anything above 125 degrees Fahrenheit should be intently monitored and that spontaneous combustion can take three to four weeks to develop.

Can I feed mouldy or dusty hay if I soak or steam it?

No. Penn State Extension states plainly that if hay is mouldy, do not feed it, and that soaking dusty hay for 5 to 30 minutes before feeding will help minimise respiratory problems associated with dust and mould spores but will not reduce the threat of mycotoxin contamination. University of Minnesota Extension found steaming reduced mould content by about 90 percent but concludes that neither soaking nor steaming should replace the main goal of feeding hay with low mould and dust content. Soaking and steaming are dust management for a horse that needs them, planned with your veterinarian, not a way to rescue a bad lot.

What should I check for in hay beyond the wrapper?

The things that are not visible from outside the bale. Toxic plants are a real risk in hay because, as Oregon State University Extension puts it, drying may improve palatability and animals fed only small amounts of hay may be hungry enough to eat the weeds. University of Minnesota Extension advises not feeding hay containing hoary alyssum to horses and notes most hoary alyssum poisoning occurs when horses eat infested hay. Blister beetles in alfalfa show why storage does not fix contamination: cantharidin is released when beetles are crushed during hay making, remains toxic in dead beetles, and does not decrease during hay storage. Check for carcasses too, as UConn advises, along with wire, plastic and other foreign material, and soil or ash from a low cut. Then have the lot sampled properly with a bale corer and analysed.

How long should a round bale last a group of horses?

Use a feeder designed for horses, site it on clean well-drained ground, and keep the interval short enough that the bale does not deteriorate before it is eaten. UConn Extension advises that if you do feed round bales it is best to have an amount horses can consume in one week, to avoid them consuming mouldy feed. That is UConn's recommendation in a botulism-prevention context rather than a universal rule, and the right interval depends on group size, weather, feeder design and how the bale is holding up. University of Minnesota Extension found that using a feeder resulted in less hay waste, 5 to 33 percent, than not using one at 57 percent, and that feeders restricting access wasted less than feeders allowing greater access. Those are figures from specific studies with specific feeders and hays rather than a guarantee for your setup.

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Sources: American Association of Equine Practitioners, botulism vaccination guidelines — the three syndromes including forage poisoning from preformed toxin in decaying plant material and carcass remnants in feed, that serotypes A, B and C are associated with most outbreaks in horses, the type B toxoid, the absence of licensed vaccines for serotypes A and C and of cross-protection, the risk-based framing, and the vaccination schedules for adults, pregnant mares and foals; page carries the note "Reviewed and revised 2019". AAEP's separate botulism disease guideline — type A prevalent in western US soil, type B spores typically east of the Mississippi and responsible for greater than 85% of cases, and type C found in carrion (aaep.org, accessed August 16, 2026; the site returns 403 to automated requests, so both pages were read directly rather than by an automated checker). Ontario Ministry of Agriculture, "Botulism in horses and haylage" — that in some outbreaks the haylage looked and smelled spoiled while in others the bales did not look spoiled, the description of type C as carrion botulism, and that a negative toxin test does not mean an animal is unaffected (ontario.ca, accessed August 16, 2026). University of Connecticut Extension, "Equine Botulism" — checking bales for small dead animals, baling below 22% moisture or using acid preservatives, keeping round bales out of the weather, spoiled material most likely internal, and the one-week consumption recommendation (extension.uconn.edu, accessed August 16, 2026). Purdue University Extension, "Is Your Hay Too Hot?" citing NRAES-18 — package-specific baling moisture targets and the heating thresholds (extension.entm.purdue.edu, accessed August 16, 2026). NDSU Extension, "Preventing Hay Fires Due to Excessive Moisture" — fire thresholds, the six-week window, the caramel or musty odour of heating hay, and the 175°F call-the-fire-department line (ndsu.edu, accessed August 16, 2026). Penn State Extension, "Mold and Mycotoxins in Horse Hay" — do not feed mouldy hay, the mould genera commonly found, the respiratory disease description, and that soaking will not reduce the threat of mycotoxin contamination; and "Sampling Bales for Forage Quality Analysis" — bale corer, cores per lot, coring large round bales from the curved edge (extension.psu.edu, accessed August 16, 2026). University of Minnesota Extension — "Selecting and Storing Horse Hay" (do not feed mouldy hay); "Steaming Horse Hay to Reduce the Effects of Mold and Dust" (about 90% mould reduction, and that neither soaking nor steaming replaces feeding low-mould, low-dust hay); "Feeding Horses in a Round Bale Feeder" (waste percentages by feeder type, herd weight loss without a feeder, injury observations, and the hay-net collapse caution); "Hoary Alyssum" (do not feed infested hay to horses, signs and timing); and "Blister Beetles in Alfalfa Hay" (cantharidin released during hay making, remaining toxic in dead beetles, not decreasing during storage) (extension.umn.edu, accessed August 16, 2026). Oregon State University Extension, EM-9871, "Avoiding Poisonous Plants in Pasture and Hay" — never include poisonous plants in hay, and drying may improve palatability (extension.oregonstate.edu, accessed August 16, 2026). University of Georgia Extension, "Baleage: Frequently Asked Questions," publication B1508 — the 40–60% and optimal 50–60% moisture ranges, the below-40% and above-65% cautions, butyric fermentation above 65%, and that botulism risk is minimized by moisture, layer count and puncture prevention; cited with the scope that it is a general livestock baleage production guide rather than a horse-feeding document (fieldreport.caes.uga.edu, accessed August 16, 2026). Commonly circulated horse-baleage figures for a transition period and for a post-opening feed-out window could not be verified in the sources reviewed here and are deliberately not published on this page. Programme, product and label requirements change; confirm current guidance with your veterinarian, your forage laboratory and the applicable product labels and equipment manuals. This page is general information and is not veterinary, nutritional or agronomic advice.

Featured photo: Horse and hay bale by Cjp24 — an Auxois horse beside a round bale of dry hay in a feeder, Burgundy, France — licensed under CC BY-SA 3.0, via Wikimedia Commons.