How the forage in hay influences the allowance of dust into equine’s respiratory system?
Measures can be taken to reduce dust in forage. Clements and Pirie (2007), found that soaking hay can halve RDCs in the breathing zone, recommending immersing hay and feeding immediately; however, Art et al. (2002) recommends avoiding soaking hay for more than 30 minutes as leaching will begin to occur after this time. A deterioration in the quality of forage may become an issue for the high nutritional needs of high-performance horses. Moore-Colyer, Taylor and James (2016) ascertained that steaming hay or soaking hay for 10 minutes were equal at reducing RDCs and that there was only a 10% difference in reduction of RDC between commercially available HayGain® and steaming in a wheelie bin (or with a kettle) and found bacterial concentrations are reduced in steaming hay but not in soaking.
The method of providing forage influences the amount of airborne dust. Vandenput et al. (1997), recommend feeding below the nostrils of horses, and Raidal, Love and Bailey (1995) say that high head carriage sustained for long periods interrupts the natural pulmonary clearance systems. Forage in hay nets/ racks may allow dust to enter the respiratory system passively as it is feeding from higher than the breathing zone (BZ) and therefore it should be avoided. However, there is a risk that horses will stale on hay on the ground and therefore not eat it.