Page 724 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Respir atory system: 3.4 Medical conditions of the lower respir atory tr act 699

VetBooks.ir Table 3.3 Environmental modification options for management of inflammatory airway disease and heaves

• Feed only good-quality hay using bales that are visibly free from any dusts or moulds when the bale is broken open. Do not feed
horses using round bales
• Soak hay by fully immersing it in water for at least 15 minutes prior to feeding. Change the water used to soak the hay daily to
prevent accumulation of endotoxins and microbes
• Feed hay on the ground. Do not use a haynet or elevated manger
• As an alternative to hay, feed ‘dust-free’ options such as haylage, hay cubes or complete pelleted rations
• Concentrates are usually an insignificant source of dust. Adding molasses to concentrates and grains may reduce the respirable dust
• Optimise ventilation by providing continuous pasture turnout (24 hours/day or as much as possible)
• Ensure appropriate ventilation of the stable
• For any period that affected horses must be indoors, house them in a stall with ventilation to the outside of the barn (e.g.
window, end of aisle near the door)
• Do not stable affected horses next to hay or straw storage or arenas. Ideally, hay or straw will be stored in a different building
• Avoid straw or sawdust as types of bedding. Use shredded paper, large wood shavings, peanut kernels or peat moss instead.
Stalls adjacent to heaves-affected horses should be managed similarly
• Affected horses should not be indoors during ‘dusty’ periods such as mucking and bedding of stalls or sweeping. A light
misting of bedding with water, before returning the horse to the stall, may also be helpful
• Regular cleaning and disinfecting of stables is recommended to prevent the persistence of dust and infectious agents in the
environment

3.159 Prognosis
Since the pathophysiology of IAD is currently
poorly understood, the long-term impact of IAD on
athletic performance of affected animals is uncer-
tain. Some animals may respond fully to treatment
and return to a normal level of performance, while
others will show variable response to treatment and
may deteriorate over time.

HEAVES

Definition/overview
Heaves is an episodic condition characterised by
obstruction of the lower airways in response to inhaled
allergens in the environment. It is also referred to as
RAO, and formerly as chronic obstructive pulmonary
disease (COPD).

Aetiology/pathophysiology
Obstruction is a consequence of bronchoconstric-
tion and airway septal thickening from inflamma-
tory cell infiltrate and oedema, as well as blockage
Fig. 3.159 The Flexineb® portable equine nebuliser of the airway by mucus and inflammatory cells.
system for the delivery of inhaled medications. Affected animals have airway hyperresponsiveness