Equine COPD - or chronic obstructive pulmonary disease - is a now-obsolete term for a common condition in horses that causes coughing and poor performance. This condition is now referred to as equine asthma and is one of the most common non-infectious lung diseases. Severe equine asthma affects 14–17% of horses in some populations, but up to 70% of pleasure horses have indicators of mild to moderate asthma. Horses affected by equine asthma typically have increased mucus production, difficulty breathing during exercise and sometimes at rest, cough, and nasal discharge. More severe cases may result in acute respiratory distress.

Equine asthma (EA) is a relatively new collective term for chronic respiratory signs in horses that range in severity from mild to severe. These conditions were previously known as inflammatory airway disease (IAD) or recurrent airway obstruction (RAO), respectively. Equine asthma is characterized by inflammation and mucous production in the lungs, which leads to lower airway obstruction. The horse may cough, and breathing may or may not be laboured. Asthma is most commonly observed in horses stabled over winter months that have become hypersensitive to dust, airborne allergens, mold spores, or mites in stable bedding or stored hay.

Chronic kidney disease (or chronic renal failure) in horses is a rare but serious disorder that interferes with normal kidney function. Your horse's kidneys perform many important processes in the body including managing blood pressure, excreting waste products, and regulating electrolyte balance. When kidney function is impaired, waste products begin to build up in the blood and affect the function of other organ systems. Horses with reduced renal function often experience weight loss and have difficulty maintaining body condition. They may also show signs of poor coat quality, excessive thirst and increased urination.

Obesity is a health concern in horses worldwide, with a prevalence estimated between 31 – 45% in some equine populations. Among ponies and easy keeper breeds, the prevalence is even higher with one study reporting that 72% of adult ponies were overweight or obese. Horses are generally considered obese when they have a body condition score of greater than 7 on the Henneke 9-point scoring system.

Stagnation edema, also known as stocking up, is a common cause of leg swelling in stabled horses. It occurs due to impaired circulation from periods of reduced activity. This short-lasting form of edema typically affects both hind limbs and causes swelling from the coronary band up to the hock. Occasionally, it occurs in the forelegs as well. Stocking up is also called distal limb edema because it affects to lower portion of the limbs. Another term for stocking up is pitting edema. This is because when pressure is applied to the area, a pit or indentation will remain temporarily. Stocking up results from the pooling of lymph, a clear fluid that circulates in the lymphatic vessels. Sometimes this circulation is compromised allowing fluid to accumulate. This typically occurs if blood flow and lymphatic drainage are impaired.

Equine influenza virus, or EIV, is an extremely contagious respiratory disease or flu affecting horses, mules, and donkeys. EIV is characterized by fever, apathy, and lack of appetite, and causes respiratory symptoms such as coughing and nasal discharge. However, some horses infected with EIV have no observable signs of the virus. Left untreated, the virus can lead to secondary infections and pneumonia. In most cases, influenza is not fatal, however, horses with impaired immune function may be more susceptible to negative outcomes.

Nutritional myodegeneration (NMD), more commonly known as white muscle disease, is a disorder that affects various animals, including horses. In equids, the condition primarily occurs in newborn foals, although adult horses can also develop it. The condition results in degeneration in the skeletal and cardiac muscle most often due to inadequate levels of selenium in the body. It also occurs less commonly in horses that are deficient in vitamin E. Selenium and vitamin E are important antioxidant nutrients for horses. Antioxidants are molecules that neutralize free radicals, which are unstable molecules that can damage cells. Common signs of white muscle disease include weakness, poor coordination, and difficulty standing, eating, and nursing. Due to a loss of muscle function, respiration can be impaired, and respiratory failure may occur in foals.

Equine pneumonia is a common respiratory illness that can be life-threatening. It can affect different parts of the horse’s lungs and may cause varied symptoms. Pneumonia refers to inflammation of the lung tissue. Upper airways and lining of the lungs (pleura) may also be involved. Horses affected by pneumonia can experience cough, fever, weakness and difficulty breathing.

Equine Infectious Anemia (EIA) is an infectious disease that affects horses and other equids, such as donkeys and mules. The disease is caused by an RNA virus transmitted by blood-sucking insects. Many affected horses show no clinical signs and are asymptomatic carriers of the disease. However, stress or illness can cause signs to become apparent. Horses that test positive for the virus must be isolated from other horses to prevent the spread of the disease. Horses infected with the EIA virus carry it for life and remain contagious.