Chronic Obstructive Pulmonary Disease (COPD)
Dr. Philip Johnson
A sample of the fluid that lines the respiratory system can be obtained using either a trans-tracheal wash or a bronchoalveolar lavage. Changes in the cells found in these respiratory system fluids are identified and used to confirm the diagnosis of bronchiolitis.
Your veterinarian may recommend specific tests in order to detect the presence of bronchiolitis or to rule out other diseases that may cause similar symptoms:
Routine blood tests (results are usually unremarkable in COPD-affected horses)
Endoscopic examination of the airways
Radiography of the lungs. Lung radiography is not routinely available for adult horses (because they are so large). The radiographic abnormalities of COPD are usually not very striking, although the test is useful for ruling out other less common lung diseases that may present with similar symptoms to COPD.
Some specialized equine respiratory diagnostic centers are able to perform some more advanced lung function tests on horses, although these tests are probably not useful in most routine cases of COPD. Some veterinarians elect to measure the oxygen content of the affected horse's blood (it may be quite low in COPD). Then the horse is treated with a bronchodilator and the oxygen content is re-evaluated. The prognosis for horses in which the blood oxygen content increases after treatment is often better than for those horses in which the bronchodilator has minimal effect.
The treatment for COPD falls into two broad categories:
Changes in Management
The most important aspect of treatment for COPD is clearly the avoidance of aeroantigens. For most COPD-affected horses, a complete recovery from the problem can be achieved simply by eliminating inhaled aeroantigens from the horse's environment. Several management adjustments can reduce the risk of exposure to inhaled aeroantigens. These include:
Maintain normal weight of your horse; avoid obesity.
Fresh (outdoor) air is usually very important, with the exception of summer pasture, which is associated COPD. Do not accommodate inside barn unless absolutely necessary. Do not allow access into the barn.
Avoid all dusty environments. Avoid excessively dusty paddocks – all dust is aggravating to horses affected with COPD.
Do not feed any hay unless absolutely necessary. Do not feed any other horses in the same pasture with hay – COPD horses may be affected by close proximity to hay and straw.
If hay must be used, use only the best quality, which is neither dusty nor moldy, although all hay is moldy to some extent. Hay that has been cut and baled in a wet spring/summer will be particularly bad in terms of mold content the following winter/spring. Barn-dried hay is preferable. Hay should be soaked under water prior to feeding by completely immersing the hay, for example in a plastic hay net, for 2 hours immediately prior to feeding. Feed in a hay net, dripping wet.
Allow access to appropriate grazing. When necessary, pasture grazing should be supplemented with oats, silage, haylage, pelleted feed, and alfalfa cubes. HorseHage™ can be used as an alternative roughage source in the diet. Beet pulp is another useful roughage for these horses. Other recommended complete pelleted rations include Purina Horse Senior and Purina Horse Chow.
Do not store hay or straw in close proximity to grazing areas – certainly not in the same air space. Hay or straw must not be stored in the same air space as indoor-accommodated horses.
Protection from particularly cold weather may be afforded by an open "lean-to" arrangement or by use of a New Zealand rug.
If indoor accommodation must be used, all horses in the communal barn should be managed under the same precautions. Avoid damp, dusty, poorly ventilated barns. Extraction fans are rarely useful (and may even be worse). They should not be used as an "excuse" for proper ventilation. Indoor environment should be kept as dust-free as possible. Do not undertake cleaning operations when COPD-affected horses are in the same environment at the risk of churning up dust.
Although an expense would be involved, you might consider special adaptation of a single stall or loose box. The stall would be sealed-off from the common air-space of the barn environment and ventilated through a high efficiency filter in association with an air-conditioner.
Minimize exposure to busy road traffic (vehicular exhaust is an aggravating factor). Do not accommodate in close proximity to busy or dusty roads.
Straw bedding should be avoided. Preferred bedding materials include peat moss, paper, clay, wetted-down wood shavings/saw dust, sand. Minimize ammonia build-up from wet bedding/urine pooling and inefficient stall drainage.
Exercise in cold weather often aggravates the problem and should be avoided.
These are intended to promote airway function. As a rule, without resort to some improvement in management, the drug strategies are rather ineffective. However, with the exception of the most severely affected horses, the use of drugs is not usually needed.
Drug strategies include the use of the following categories of drugs:
It is currently recommended that bronchodilators and anti-inflammatory agents (usually steroids) should be administered via inhalation.