Causes of respiratory diseases in horses
Is your horse suffering from a cough, nasal discharge, a loss of performance or even having difficulty breathing?
The reasons for this are varied. Possible causes include infectious diseases caused by pathogens such as:
- Viruses
- Bacteria and
- Parasites
Sensitive horses, a weakened immune system, and contaminated feed promote infections. Acute respiratory diseases are often treated too late or insufficiently, leading to recurring infections or even chronic diseases.
These chronic, non-infectious disease courses can also trigger the same symptoms listed above.
Don't ignore the first signs
Often, horse owners only notice a slight cough. A few small coughs may be noticeable at the beginning of riding. After training, some horses may also exhibit a slight nasal discharge. However, these signs are often not just a "minor cough" and "a little nasal discharge," but rather the beginning of a chronic condition.
Failure to treat can have serious consequences. A "minor cough" and a "bit of nasal discharge" can develop into a serious, chronic problem sooner than you'd like. The course of such chronic respiratory diseases varies, and not every horse suffers the same suffering. However, it's clear that persistent respiratory inflammation will not only significantly impair your horse's performance but also its quality of life. One of the worst cases is absolute respiratory distress, even during rest periods.
What can horse owners do to best support their horses with respiratory problems?
The answer always lies in appropriate bedding and feeding management.
Since the domestication of horses, they have been dependent on humans. The original wild horse roamed the steppe in herds, grazing on a variety of plant material.
Today's working horse, on the other hand, is usually kept in open, loose, or box stables on bedding we select and eats roughage provided by humans. This housing and feeding inevitably exposes the horse to significantly more dust. It is now up to the horse owner to keep the horse healthy. This also includes creating an environment for the horses that is as dust-free as possible.
But here lies the crux of the matter. Since horses are so-called "continuous feeders," meaning they are ideally occupied with eating for over 15 hours a day, their noses are constantly in the dusty bedding and even dustier roughage.
Hay as traditional roughage
In our latitudes, it's not possible to guarantee horses a vegetation-free winter and thus year-round pasture feeding. However, humans must continue to ensure that horses are provided with sufficient roughage-rich forage. This is achieved by preserving the grass as their forage.
The most traditional method for this is haymaking.
However, hay is the most significant factor in the development of inflammatory processes in the respiratory tract. It is produced through the drying process. A byproduct of inadequate drying is a multitude of mites, bacteria, and mold. Dust is also considered another typical problem with this product.
It has long been known that even hygienically high-quality hay contains a high concentration of harmful microbes due to the preservation process (Vandenput et al., 1997). The most frequently complained about problem among horse owners is respiratory disease (Holmquist et al., 2002). A study by CE Müller demonstrates that the vast majority of horse owners and handlers have had negative experiences with feeding hay to their respiratory tract. This is also confirmed by an analysis by Von Clausen et al., which already demonstrated in 2004 that respiratory disease is the second most common reason for euthanizing horses.
Haylage and silage as alternatives to traditional hay?
As a roughage with less dust and less microbes, haylage is, in theory, an alternative to conventional hay. Unfortunately, in practice, the opposite is often the case.
Inadequate silage processing or processing errors can lead to the development of microorganisms such as Cloristides, Enterobacteriaceae, and Listerine in the haylage. These bacteria cause anaerobic spoilage of the haylage. This, in turn, triggers aerobic spoilage by organisms such as mold and yeast. Fermentation products and the acidity in the silage can also lead to serious illnesses. There is also a risk of botulism, a life-threatening poisoning caused by small animals in the preserved bales.
Gastrointestinal disorders such as colic or loose stools are often associated with feeding haylage. Studies such as those by MJS Moore-Colyer and AC Longland demonstrate horse owners' fear of feeding haylage, as the vast majority have negative experiences with this roughage.
Other supposed alternatives on the way to hygienic roughage
Many horse owners and now even entire stable operators use watering of the hay to protect horses from the dust contained in the hay.
The primary goal of this method is to bind the dust from the hay, preventing it from entering the horses' respiratory tract. Watering also binds the dust effectively, but it also causes the leaching of the nutrients contained within and a massive proliferation of microbes. An increased burden of bacteria, yeasts, mold, etc. is not effective, as these also cause health-threatening problems such as diarrhea, reduced lung function, liver damage, and so on.
To what extent does inhalation and food supplements help with respiratory problems?
Every horse owner fears a diagnosis of COPD, RAO, or IAD. But what should you do if your veterinarian has diagnosed it that way?
Many horse owners resort to tried-and-true treatments such as inhalations, medication, or supplements. These work well to some extent, but they cannot address the root cause of the problem.
It is important to eliminate the cause and not just treat the symptoms!
But how can one effectively maintain roughage at a high hygienic level while binding breathable dust and killing harmful microorganisms?
The answer is unconventional and unfortunately not quite as widespread as the method of watering, namely steaming hay!
Scientific studies by renowned scientists who have been researching this field for years, such as Moore-Colyer, James, Stockdale, Leggatt, and many others, show that steaming hay completely eliminates yeasts and fungi, such as the harmful fungus Aspergillus. In addition, bacteria are also killed by the hot steam. Respirable dust is reduced by up to 94% using this method.
The concept of steaming hay is straightforward. Similar to a steamer, the nutrients are preserved. Only the NSC (non-structural carbohydrate) content is reduced. However, sugar and starch are not necessarily considered desirable ingredients in hay, as they can trigger insulin imbalances. This imbalance in insulin production often leads to conditions such as equine metabolic syndrome (EMS), laminitis, and equine polysaccharide storage myopathy (PSSM).
Hay steaming has proven effective not only in theory but also in practice for horses suffering from respiratory diseases. In summary, as with soaking, it achieves very high levels of dust binding and, in addition, eliminates the harmful microbes it contains. Furthermore, steaming hay can be used successfully for gastrointestinal diseases caused by bacteria.
Even for horses that are only allowed to consume a few water-soluble carbohydrates (WSC) and non-structural carbohydrates (NSC) due to illness, steaming hay proves to be a suitable partner for daily roughage feeding.
Further studies on this topic:
- James, R. & Moore-Colyer, MJS [2013] Hay for horses: The nutrient content of hay before and after steam treatment in a commercial hay steamer. Proceedings of British Society of Animal Science Conference, Nottingham April 2013.
- Von Clausen, M., Preisinger, R. & Kalm, E. [2004]. Analysis of disease data in German warmblood breeding. Züchtungskunde 62 , pp. 167-178.
- Holmquist, S. & Müller, C.E. [2002]. Problems related to feeding forages to horses. Proceedings of the XIIIth International Silage Conference , pp. 152-153.
Author:
Dana Böhnke [2018]: “Influence of roughage quality and type of preservation on feed intake and acceptance in horses”.
