Stable hygiene · The evidence
Stable hygiene: removing the hazards
Equine8 · updated
This page reviews veterinary and public-health research on stable hygiene. Disease figures describe the evidence in general and are not claims about any EQ8 product; the organisations and authors cited do not endorse EQ8. Ask your vet about any sick horse.
At a glance
- 34 daysthe longest the strangles bacterium survived in a wet bucket in winter[1]
- 1–3 daysits survival outdoors in summer sun[2]
- 0/8halters still contaminated after a 60 °C wash, against 7 of 8 at 40 °C[3]
- ~10%horses in strangles outbreaks whose guttural pouches fail to clear[4]
- 12–20 monthshow long ringworm spores can stay viable in the environment[5]
What a Swedish study found
Routine cleaning and disinfection removed live strangles bacteria (Streptococcus equi subsp. equi) from concrete, raw wood, plastic and leather. Polyester webbing halters stayed contaminated until they were washed at 60 °C.[3]
How it was done. Researchers soaked used stable materials with a strong culture of a laboratory strain, or a strain from a horse carrying the infection without signs. The pieces were kept indoors at 10–18 °C, out of sunlight. Three days later, half were scrubbed for one minute with detergent, left 10 minutes, rinsed, then soaked in a peroxygen disinfectant and left two days. Plastic carrying the clinical strain was disinfected with a chlorine-based product, ECO horse Removeit,[3] which its maker describes as hypochlorous-based.[6] The paper gives no strength or contact time for it.[3]
Cleaning cleared every material except polyester webbing
SamplesUntreatedCleaned and disinfected
Samples still positive for S. equi (out of 8)
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| Polyester halter laundering | Still positive |
|---|---|
| 40 °C wash, air-dried | 7/8 |
| 40 °C wash, then 70 °C tumble dryer | 7/8 |
| 60 °C wash | 0/8 |
What it means for a yard.
- Hard and rough surfaces, including concrete and unsealed wood, can be cleared by the right sequence: scrub with detergent, rinse, then disinfect.
- Woven synthetic tack holds moisture and bacteria. It needs a 60 °C wash, not a spray.
- Leather supported the bacterium poorly even without cleaning, probably because of tanning residues.[3]
- Untreated surfaces stayed positive for at least five days, so stables and kit are a real route between horses.[3]
Limits the authors state. The work was indoors at a steady temperature; the contamination may not match a real outbreak; there were no body secretions; and results were recorded only as positive or negative.[3]
How long hazards last in a stable
Sunlight and dry air kill most stable pathogens within days, but water, wet surfaces, winter and dried manure let some last for weeks, months or years.[2][1][10]
Wet and cold conditions let hazards last for weeks
Longest survival reported, days (log scale)
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| Hazard | How it spreads in a stable | What the guidance says |
|---|---|---|
| Strangles (S. equi) | Horse to horse, shared water and feed, handlers’ clothes and equipment[4] | Remove organic matter, then disinfect; disinfect water and feed buckets daily in an outbreak[4] |
| Equine herpesvirus (EHV-1) | Clothing, footwear, shared grooming kit and tack, water, stalls and tie points[9] | Isolate cases; quarantine the premises at least 28 days after the last new case[11] |
| Equine influenza | Aerosols up to about 45 m, hands, brushes, shared buckets[7] | Isolate 14 days; easily killed by many common disinfectants[7] |
| Salmonella | Faeces, drains, cracks and corners, waterers[12][13] | Remove organic matter first; avoid pressure washers, which spread it in aerosols[10] |
| Ringworm (dermatophytes) | Brushes, clippers, tack, rugs[5][14] | Clean kit of debris, use a product labelled for Trichophyton; wash textiles at 60 °C, as drying and freezing do not kill spores[14][15] |
| Rhodococcus equi | Dusty soil enriched with horse faeces; foals in stables had 17.3 times the odds of exposure[16] | Remove faeces, water dusty lanes, limit dust[16] |
| MRSA and C. difficile | MRSA passes between horses and people; C. difficile spores were found on 8.3% of hospital surfaces[17][18] | Hand hygiene for people; spores need sporicidal products after cleaning[19] |
| Rotavirus (foals) | Faeces; hard to inactivate[20] | Chlorine and iodine products worked, but organic matter reduced their effect[20] |
Where hazards live: explore the stable
Choose a zone to see the hazard, the evidence and what to do.
Zone 1 of 11
Stall walls and wood
Hazard: Bacteria and viruses on rough, porous surfaces.
Evidence: Unsealed wood was cleared of the strangles bacterium after detergent, rinse and disinfectant.[3]
What to do: Scrub with detergent, rinse, let dry, then disinfect and keep wet for the label contact time. Seal or replace damaged wood.
Clean first, then disinfect
Without cleaning, disinfection does not work: manure, urine, bedding, saliva and mucus shield microbes and use up disinfectants, chlorine products among them.[19][4]
- Move the horse out and open the stable to light and air.[2]
- Remove all bedding, manure and feed. Organic matter is the single biggest reason disinfection fails.[19]
- Dry-brush walls, fittings and corners, with the horse out, since mucking out raises dust nearly 16-fold.[22]
- Scrub with detergent, using a foaming product on rough surfaces.[4]
- Rinse off the detergent, because soap residues inactivate many disinfectants.[23]
- Let it dry, so the disinfectant is not diluted.[19]
- Apply disinfectant and keep the surface wet for the full contact time on the label. Porous, cracked wood and earth floors need longer.[23]
- Ventilate and let it dry before the horse and fresh bedding return.[4]
Avoid pressure washers. High-pressure spray can lift bacteria into aerosols and spread them.[4][10]
Wood is the hardest surface. Unsealed wood needs time to dry, and badly damaged wood may be best replaced or sealed.[4][24]
Where hypochlorous fits
Hypochlorous is a fast-acting oxidant that reacts with proteins and energy systems inside microbes and stops them copying their DNA, and it is the main germ-killing form of chlorine.[37][32] It works best as the last step on a surface that has already been cleaned.[38]
Why form matters. The microbe-killing activity of chlorine comes largely from undissociated hypochlorous, and it falls as pH rises.[32] Household bleach is strongly alkaline, so almost all its chlorine is hypochlorite ion. Rydén and colleagues note an older report that sodium hypochlorite diluted to label strength was poorly effective against the strangles bacterium.[3]
Below about pH 7.5, most chlorine is hypochlorous; at bleach’s pH almost none is
Evidence from the strangles research. In the Swedish study, plastic carrying the clinical strain was cleared (0 of 8) after detergent and a disinfectant that its maker describes as hypochlorous-based.[3][6] In a separate study of equipment used on carriers, sodium hypochlorite was the only disinfectant that removed bacterial DNA as well as live bacteria.[30]
Evidence from animal housing.
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| Setting | Strength | Result |
|---|---|---|
| Poultry house surfaces[25] | Slightly acidic hypochlorous water, 250 mg/L | Reduced bacteria on floors, walls, troughs and pipes more than benzalkonium chloride or povidone-iodine in this study; rinsing first improved results |
| Layer house floors and troughs[26] | 80–100 mg/L | Greater reduction than povidone-iodine on floors and feed troughs in this study; protein load reduced efficacy |
| Clothing, boots and iron[27] | 220 mg/L, 2.5 min | About 2.4–2.6 log reductions; porous materials did worst |
| Pig transport vehicles[28] | 200 mg/L, high pressure | About a 1.5 log reduction in bacterial counts |
| Laying-hen drinking lines[29] | 0.3 mg/L | Sustained inhibition of bacteria in the lines, about 3 log; egg quality unaffected |
| Twitches used on strangles carriers[30] | Sodium hypochlorite | The only disinfectant tested that removed detectable bacterial DNA as well as live bacteria |
Dirt is the limit. About 1 g/L of protein used up electrolysed water at 360–400 mg/L free chlorine in laboratory tests, and proteins and sugars consume hypochlorous rapidly.[38][39] That is why veterinary disinfectant standards are tested under heavy soiling, much dirtier than medical tests.[34][36]
Veterinary tests use about seven times more dirt than medical ones
Organic soiling in the test, grams of protein and yeast per litre
What hypochlorous cannot do
- Clean. It does not remove manure, bedding or biofilm; detergent and scrubbing do.[19]
- Replace laundry. Woven fabrics held the strangles bacterium through a 40 °C wash; only 60 °C cleared it.[3]
- Work through porous surfaces. In tests on clothing, boots and iron, porous materials did worst.[27]
- Survive light and heat in storage. It breaks down in UV, sunlight, air and heat, so keep it closed, cool and dark.[39][31]
- Show proof against the strangles bacterium itself. We found no published test of hypochlorous against S. equi, equine herpesvirus or equine influenza, and no study on leather or tack finishes.
Chemical safety in the stable
Never mix chlorine products with ammonia or acids. Hypochlorite releases chlorine gas when acidified, and forms chloramines with ammonia; both irritate the airways, and severe chlorine exposure can injure the lungs up to 36 hours later.[40]
Urine and chlorine. Hypochlorous reacts with ammonia step by step to form monochloramine, dichloramine and trichloramine. Chloramines are far weaker disinfectants, and trichloramine, the most volatile, forms at low pH or high chlorine doses.[41] In indoor pools, trichloramine above 0.5 mg/m³ was linked to red, itchy eyes and runny noses.[42] So remove wet bedding and rinse urine away before disinfecting, and keep the stable ventilated.
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| Gas | 8-hour limit | 15-minute limit |
|---|---|---|
| Ammonia | 25 ppm | 35 ppm |
| Chlorine | – | 0.5 ppm |
Source: HSE EH40.[43] Other disinfectants carry their own risks: phenolics above 2% are highly toxic to animals, and surfaces should be rinsed before animals return where the label says so.[19]
Air quality: ammonia, dust and mould
Stable air is a hazard in its own right. Severe equine asthma affects about 14–17% of horses in cool northern climates, and organic dust from hay and bedding is the main driver.[44] Hypochlorous does not remove ammonia or dust; bedding, forage and ventilation do.
Straw pellets released about a third of the ammonia of wheat straw
Ammonia just above the bedding, mg/m³
- Fitting mechanical ventilation cut median ammonia in one stable from 3,200 to 1,330 µg/m³, though airborne endotoxin and fungi rose.[46]
- Hay fed from racks gives 2–3 times more dust than hay fed from the ground, and switching from hay and straw to haylage and shavings cut dust by more than 97%.[22]
- UK workplace limits for people are 25 ppm ammonia over 8 hours.[43]
Water, feed and laundry
Shared water is one of the clearest routes for strangles: the bacterium lasts 4–6 weeks in water, and in one study horses sharing troughs had higher odds of the disease (adjusted odds ratio 7.74).[4][47]
- No shared water or feed buckets during an outbreak; empty, scrub and disinfect them daily.[4]
- Disinfect field troughs regularly at all times.[48]
- Wash synthetic tack, rugs and numnahs at 60 °C; a 60 °C wash also removed ringworm spores, while tumble-drying and freezing did not.[3][15]
Only a 60 °C wash cleared polyester halters
Halter pieces still positive (out of 8)
If there is an outbreak
Strangles is one of the most frequently diagnosed infectious diseases of horses, and the guidance for it is the most detailed. The same principles apply to equine herpesvirus, for which quarantine lasts at least 28 days after the last new case.[50][11]
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| Area | Routine | During a strangles outbreak |
|---|---|---|
| New arrivals | Ideally 3–4 weeks’ quarantine with daily temperatures and screening[48] | Isolate at least 3 weeks; screen before mixing[4] |
| Temperatures | Watch for fever in new or unwell horses | Twice daily for all in-contact horses; act on fever before discharge appears[49][4] |
| Grouping | Normal turnout groups | Red (cases), amber (contacts within 3 weeks), green (no contact), with separate staff and kit[49] |
| Water and feed | Regular trough cleaning[48] | No sharing; disinfect buckets daily[4] |
| Stables and kit | Clean, then disinfect, on a routine schedule | Disinfect anything used in the past 3 weeks; red-label equipment for cases[49] |
| People | Clean hands and boots between yards | Dedicated staff or work from lowest to highest risk; protective clothing; tell farrier, vet and visitors[4][49] |
| Transport | Clean and disinfect after each use[4] | No movements on or off the yard |
| Ending it | – | Quarantine until at least 3 weeks after the last case resolves, and clearance testing of recovered horses[4][48] |
A routine schedule
A simple routine, built from the guidance above, that a yard can print and pin up.
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| When | What |
|---|---|
| Daily | Muck out with the horse outside; empty, scrub and refill buckets; check temperatures of new or unwell horses |
| Weekly | Scrub and disinfect mangers, troughs, grooming kit and tack; wash numnahs and boots |
| After a show or transport | Clean and disinfect the horsebox; wash travel rugs at 60 °C; watch temperatures for 3 weeks |
| New arrival | Quarantine 3–4 weeks with its own kit and buckets; screening as your vet advises |
| Deep clean, at least twice a year | Strip stables, scrub walls and floors, rinse, dry, disinfect; seal or replace damaged wood; clean drains |
What the evidence does not yet show
- No published study has tested hypochlorous on its own against the strangles bacterium, equine herpesvirus or equine influenza.
- No study has tested hypochlorous on leather or tack finishes, or for fogging stables.
- The Swedish study was indoors at a steady temperature, with laboratory contamination.[3]
- There is no equine-specific evidence on trough biofilm.
Where EQ8 fits
EQ8 DEFEND Multipurpose Sanitising Spray (500 ml, 675 ppm) and Liquid (20 L, 2000 ppm) are certified to EN 13727, EN 13624, EN 14476 and EN 17126.[51] These are medical-area laboratory tests; the products have not been tested to the veterinary standards described above. Use them as the final step on cleaned surfaces, as each label directs.
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