Racehorse Lung Ailment

Beta-Agonist Drugs: Effect on Respiratory Function in Horses

Horses in intense exercise, such as racing or three-day eventing, need full lung capacity to perform to the top of their abilities. Hoping to give their horse every advantage, some racehorse trainers medicate with beta-agonist drugs, like clenbuterol (a drug commonly used to treat chronic obstructive pulmonary disease), in an attempt to improve airway function. But is such medication actually effective in horses? At the 2011 America College of Veterinary Internal Medicine Forum, held June 15-18 in Denver, Colo., Rose Nolen-Walston, DVM, Dipl. ACVIM, assistant professor in the department of clinical sciences at the University of Pennsylvania's College of Veterinary Medicine, discussed the effects of beta-agonist drugs on the equine lung.

Nolen-Walston explained that what these medications can do is often misunderstood and, therefore, the drugs are often misused. Beta-agonist drugs are designed to inhibit bronchospasm (constriction) of the airways in horses affected by airway inflammation, she noted, and healthy horses typically don't achieve dilation of the small airways in response to treatment with clenbuterol.

Clenbuterol is the only beta-agonist drug currently approved for use in horses and is primarily used to treat breathing problems. Clenbuterol also has anaboliclike effects that shift a horse's body mass from fat to muscle; however, Nolen-Walston noted that its use has not been scientifically associated with any increase in performance. In fact, she added, its ergonomic effects could negatively affect performance and include:

"One potential issue with using beta-agonist medications is the development of tachyphylaxis, which is the tolerance or desensitization to effects of a drug after chronic administration," she cautioned, referencing one study that revealed that by Day 21 of clenbuterol administration, some horses' airways had become hyper-reactive not just due to loss of effect but also from worsening of pulmonary function. The same study revealed that a peak effect is generally seen by Day 14, so Nolen-Walston recommended limiting its use to two weeks.

Learn more about the importance of nutrition, vaccinations, and deworming programs designed to keep your horse healthy in Understanding Equine Preventive Medicine .

Another commonly used beta-agonist in horses is albuterol, which has an onset time of about five minutes, but only provides positive effects for about 30-60 minutes, she said. It is administered via a nebulizer or with a metered dose inhaler sprayed into a specialized equine breathing mask. Nolen-Walston said that pretreatment with vitamin C can increase sensitivity to albuterol three- to tenfold and decreases tachyphylaxis. However, she pointed out that oral-administered albuterol achieves minimal bioavailability (the rate at which a drug is absorbed or becomes available at the site of physiologic activity after administration).

Lung disease in the racehorse | projectorlamp

Lung disease in the racehorse

Posted by projectorlamp on 20 de abril de 2011

EQUINE ATHLETES are faster, stronger, and tougher than most of their pasture-grazing relatives, but are they any healthier? The answer to that question may surprise you.

Racehorses represent a section of the equine population that is well cared for, fit, and receiving regular strenuous exercise. They are some of the most elite athletes of the equine world. Yet racehorses are much more likely than slower, weaker, less fit horses to develop lung infections such as pneumonia, infectious bronchitis, and lung aThis page list rubber hose products with details & specifications.bscesses.

The types of viruses and bacteria that tend to cause these problems in racehorses are not exotic or particularly aggressive strains, either. They are the types of infectious agents that all horses are exposed to and that are generally fought off by the average immune system.

Racehorses seem unable to successfully defend themselves against causes of lung disease, and Dorothy Ainsworth,Our Polymax RUBBER SHEET range includes all commercial and specialist D.V.M., Ph.D., a veterinary researcher, clinician, and professor of large animal medicine at Cornell University, is looking into the reasons why.

Career threat

“One of the greatest risk factors for developing pneumonia, pleuritis [an infection of the lining of the lungs and chest], or lung abscesses in athletic horses is strenuous exercise or racing itself,” Ainsworth said.

“Equine athletes get lung infections such as pneumonia, infectious bronchitis, and lung abscesses significantly more often than other horses do,” Ainsworth said. “Because of immunosuppression [caused by a racehorse's environmental conditions and exercise demands], various bacteria and other agents can take advantage of the depressed respiratory-tract defense mechanisms. We need to improve the pulmonary defense mechanisms so that viruses and bacteria can be effectively cleared before they are able to proliferate and cause illness.”

Aside from the time lost to actual infections, respiratory diseases often require lengthy convalescent periods. Because the time schedule for a racehorse to compete, win, and establish itself often is so short, any time lost effectively can close the door on a career.

“Respiratory disease is so important that it is second only to lameness as the most common cause of decreased performance, lost training days, and premature retirement among racehorses,” said Ainsworth. Yet it is becoming apparent that racing and strenuous exercise, the actual substance of being a racehorse, is exactly what is putting these horses at risk.

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