Researchers from Portugal have identified a troubling weakness in efforts to manage horses with asthma: The failure of owners to follow the recommendations made by veterinarians to reduce exposure to environmental irritants that worsen the condition.

In a study conducted at the University of Lisbon, researchers focused on 39 mature horses diagnosed with severe equine asthma (SEA)—a respiratory condition previously known as recurrent airway obstruction or “heaves”—at the veterinary clinic. Characterized by airway inflammation, coughing and labored breathing, SEA is triggered by environmental factors, such as dust and mold, but when a horse is carefully managed to reduce exposure to these irritants the clinical signs usually subside.

At the time of each horse’s diagnosis, the owners filled out a questionnaire describing how the animal was housed and fed, as well the signs of respiratory problems that the owner had observed. The consulting veterinarian then gave the owners a set of six management recommendations, ranging from improving the barn ventilation to simply turning horses out as much as possible and feeding pelleted feed, cubed forage, or hay that had been immersed in water for 20 to 30 minutes to minimize dust exposure.

One year after the initial visit, the researchers contacted the owners to determine if they had followed the recommendations and to see how the horses were faring. They found that only a limited number of owners had followed more than a few of the recommendations. Only 3 of the 38 owners had implemented all six of the management measures and only six owners had adopted five of the measures. Three or four recommendations were adopted by 33.3 percent of the owners and about half of the owners had adopted one or two of the suggested recommendations.

At the same time, the data also showed that recommended measures were effective: Researchers found a direct statistical correlation between a horse’s improvement and the owner’s efforts.

“When owners were able to follow these guidelines, they reported that their horses significantly improved,” says Joana Simões, MSc. “On the other hand, when the owners reported failure to comply with the guidelines, their horses remained symptomatic and required medical treatment.”

Some of the management changes were more effective than others, says Simões. “Hay seemed to have a particular influence on the clinical status of the horses. In fact, most owners reported that their horses tended to cough when fed dry hay.” Despite this, only nine of the owners reported soaking their horse’s hay, following the recommendations. Increased turnout, keeping the horse outside during grooming and stall cleaning and using low-dust bed- ding also proved to be statistically significant in regards to reducing clini-cal signs of SEA and the need for medications.

Simões says it’s understandable that owners were not able to implement every suggestion. “It is important to differentiate between recommendations that involved modifying or creating new infrastructures, such as remodeling the ventilation or building a paddock, from those which comprised altering daily routines. In the first scenario, failure to adopt the recommendations was either related to lack of space or financial issues, which of course is a very difficult problem to overcome.”

Yet some owners were still unwilling or unable to make less difficult changes. “Changing daily routines is also not an easy task, specifically if the owner or caretaker has other animals in his care,” says Simões. “This reluctance was observed in the feeding of dry hay or poorly soaked hay to the SEA-affected horses. Owners claimed they were not willing to sub-stitute the horse’s forage, or that soaking the hay for 20 minutes required altering their routine and interfered with their schedule. In some cases owners also re- ported that although having explained the importance of properly soaking the hay, they could not get the horse’s caretaker to fully comply with their instructions.”

Simões says that the lack of owner compliance may stem from SEA being a disease that can only be managed, not cured. “In general, people have become accustomed to rapidly solving medical issues by simply taking a pill or doing a protocol for a certain amount of time, but unfortunately there is no cure or quick solution for SEA. It has an insidious nature and affected horses have periods of remission and exacerbation, mostly associated with the amount of respirable dust particles they are exposed to.”

Owners may be more willing to undertake the long-term effort of managing a horse with SEA, says Simões, if they better understand the nature of the disease and their role in its progression. “People tend to have a better understanding if they can somehow relate to the situation, so it might help to compare the horse with their asthmatic friend or family member,” she says. “I sometimes ask owners to just sit in their horse’s stall for 20 minutes during periods of high activity and to also inhale deeply the scent of the hay. If they feel it is too dusty, then that is also true for the horse.”

Reference: “Owner compliance to an environmental management protocol for severe equine asthma syndrome,” Journal of Equine Veterinary Science, April 2020

GUIDELINES FOR MANAGING HORSES WITH ASTHMA

In a recent study conducted in Portugal, veterinarians gave these environmental management guidelines to the owners of horses diagnosed as having severe equine asthma (SEA).

1. Ensure housing has good ventilation (at least two openings for air circulation)

2. Avoid stabling if possible, instead keep the horse on pasture

3. Turn out the horse for as long as possible, at least 12 hours a day

4. Move horses outside for grooming or when stalls are being cleaned

5. Use commercial dust-free bedding such as shavings, cardboard or low-dust options and avoid materials with potentially high dust content, such as sawdust or straw

6. Do not feed dry hay because of its high dust concentration. Feed cubed or pelleted feeds or completely immerse hay meals in water for 20 to 30 minutes before feeding it to the horse.

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