L.A.D. Theory Discussion: A recent study done in Europe looking at poor performance in horses and the huge percentage that ended up being the result of LAD (lower airway disease)!!!!! These were horses that were not presented for mucous problems, coughs, etc etc……purely for poor performance. And a large percentage ended up being diagnosed as having LAD – The point is that horses with poor performance of unknown cause could be a candidate for EST (Equine Salt Therapy) based purely on the likelihood of being associated with LAD.
Clinicians have recognized that there are other types of chronic airway diseases in horses for which a diagnosis of heaves (RAO) does not fit. Young athletic horses, for example, are commonly afflicted by lower airway inflammation that results in excess mucus within the lungs and poor exercise performance. It is possible that, over a period of years, this condition progresses to full-blown heaves (and therefore shares a common cause with heaves). However, although some researchers suspect a link between these two conditions, currently there is no evidence to support this contention. For the moment, this chronic respiratory disorder in young horses is termed inflammatory airway disease (IAD). The term small airway inflammatory disease (SAID) has also been applied in this same context.
The early signs of LAD can be quite subtle, including a mild nasal discharge (which can have a white, creamy appearance or be more yellow in colour), a cough that is most notable during and after exercise and perhaps a lack of vigour during exercise. The horse might cough repeatedly, particularly during feeding or other activities that can increase the amount of respiratory irritants in the horse’s immediate environment (e.g., stall mucking and re-bedding). A horse might cough in a series of spasms, as if unable to “clear his throat.” The rate and depth of breathing might be increased (the normal resting respiratory rate in adult horses is 12-20 breaths per minute, slightly higher in salt room particularly for first visit).
Typically, there is a progressive worsening of clinical signs over a period of months to years. Importantly, however, appropriate Salt Therapy treatment and prevention measures can slow or even halt the progression of illness.
In severely “heavey” horses, characteristic signs include frequent coughing, exercise intolerance, and labored breathing–almost like a horse recovering from a hard bout of exercise. Rather than the gentle chest motion associated with restful breathing, there is a marked increase in chest movement, nostril flaring, and a noticeable abdominal push during expiration. To compensate for the airway obstruction, the horse uses his abdominal muscles in an attempt to generate greater airflow. These abdominal muscles enlarge in response to the extra work, resulting in development of a characteristic “heave line.” This extra effort can also take its toll on the horse’s energy reserves–some horses with severe heaves will lose weight.
The signs of IAD/SAID are much more subtle and most often recognized in horses (e.g., racehorses, eventers, endurance horses) required to undertake strenuous athletic activities, where even minor changes in the efficiency of lung function can limit “top-end” performance. Some reduction in athletic performance is the first clue. Affected racehorses will finish races poorly; riders might complain that the horses are lazy or lethargic during work. Other riders might report that horses cough or toss their heads during “collection,” perhaps because there is further obstruction to airflow with neck flexion. In general, the negative effects of IAD/SAID on performance are particularly noticeable in hot weather.
The airways that make up the lung are not rigid structures. Their diameter is controlled by a layer of muscle. Inflammation leads to a constriction or tightening of this muscle, the result being a restriction of air flow through the lung. The inflammation also results in thickening of the airway walls and an increase in mucus production. All of these factors obstruct airflow and lead to the clinical signs of respiratory disease and poor exercise performance.
Making the Diagnosis
Step number one in the management of these chronic lung problems is confirming the diagnosis. In horses with severe heaves, the diagnosis is often based on clinical features (e.g., chronic cough that worsens when the horse is housed indoors) and lack of evidence of a bacterial or viral respiratory disease (e.g., no history of fever). On the other hand, the diagnosis of IAD/SAID and mild heaves requires some specialized tests, including endoscopic examination, bronchoalveolar lavage (BAL), and, in some cases, tests of lung function.
Visualization of the windpipe (trachea) with an endoscope is helpful for detection of excess mucus in the airways. It is sometimes helpful to perform this examination about 30 minutes after a bout of exercise, which tends to increase the amount of mucus in the trachea.
Breathing Relief
Fortunately, there are ways to provide relief from the airway obstruction that plagues horses with heaves and IAD/SAID, and in many cases allow their return to full athletic function. In some young horses, IAD/SAID appears to be due to repeated bacterial infections of the larger airways. As horses develop immunity to these organisms, the IAD/SAID is self-limiting.
By contrast, there is no cure for heaves (and, probably, IAD/SAID). Affected horses will remain prone to “heavey” episodes, particularly when we fail to minimize exposure to dust and other environmental pollutants. As well, realize that over time there can be permanent lung scarring and loss of function that is no longer reversible. This can be averted by recognition and proper preventative management with salt therapy.
In general, Salt therapy is used for the first two to three weeks of treatment, giving the horse breathing relief enabling the mineral salts to deal with the inflammation. (Severely affected horses might require treatment indefinitely).
Top trainers are using Salt Therapy 30-40 minutes before a conditioning session to allow the horse to train properly. Horses with LAD, significant improvement in lung function can occur within three days of consecutive salt therapy treatments 15 minutes each day!
Finally, it should be stressed that even in the face of top-notch environmental controls, horses prone to heaves or IAD/SAID are at continual risk for occasional flare-ups that require periodic treatments. Watch for the early, tell-tale signs (such as excessive coughing) and call your veterinarian as soon as possible so that Equine Salt Therapy can be started without delay! Government funded studies are scheduled to verify Equine Salt Therapy L.A.D Theory
