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  Discussion on Research Summary: Reducing Respiratory Dust Concentrations
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Moderator:
DrO

Posted on Thursday, Sep 27, 2007 - 6:55 am:

Here are two studies that look at ways to improve barn management with fairly expected results: removing hay and straw from the environment will reduce the amount of dust in your barn. Woodshavings and haylage are substituted and compared. Soaking or wetting hay are also found to reduce barn dust but I would emphasize there is work that shows this does not substantially reduce the concentration of hay molds in the trachea of horses and it does reduce the nutritional content of the hay.
DrO

Res Vet Sci. 2007 Oct;83(2):256-62.
Respirable dust concentrations in equine stables. Part 1: validation of equipment and effect of various management systems.

Clements JM, Pirie RS.
Division of Veterinary Clinical Studies, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, United Kingdom. jennyswain@hotmail.com

Traditional methods of measuring airborne dust concentrations (ADC) in animal housing have included the collection of dust onto pre-weighed filters permitting the calculation of mean, not maximum, ADC. However real-time continuous particle monitors are advantageous in identifying short duration elevations in ADC which may be detrimental to equine respiratory health in the face of a relatively low mean ADC. These monitors have not previously been used to measure ADC in equine stables. Comparisons of a filter-based sampler and a real-time continuous particle monitor revealed no significant difference (P=0.079) and good agreement (>or=95% of the points fell within two standard deviations of the mean of the differences and the mean of the differences approximated zero) between the devices, with respect to mean respirable dust concentration (RDC) measurements. Investigations of the influence of various equine management systems on RDC revealed that both mean and maximum breathing zone RDC were significantly reduced (P<0.05) in equine stables by changing the environment from hay feed and straw bedding, to haylage feed and wood shavings bedding (reduction in mean - 0.0867mg/m(3) to 0.0260mg/m(3); reduction in maximum - 4.0758mg/m(3) to 0.2182mg/m(3), respectively).

Res Vet Sci. 2007 Oct;83(2):263-8.
Respirable dust concentrations in equine stables. Part 2: the benefits of soaking hay and optimising the environment in a neighbouring stable.

Clements JM, Pirie RS.
Division of Veterinary Clinical Studies, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, United Kingdom. jennyswain@hotmail.com

The effect of soaking hay to minimise equine breathing zone respirable dust concentration (RDC) is unknown, as is the duration of soaking required. Additionally, the influence of the bedding and forage used in one stable on the mean and maximum RDC in a neighbouring stable within a common airspace is unknown. Consequently, in the management of equine environmental respiratory disease uncertainty remains about the necessity for optimising conditions in neighbouring stables. Investigations using a real-time continuous particle monitor revealed that when feeding hay, horses' mean breathing zone RDC was significantly reduced if the hay was immersed or soaked for a prolonged time, prior to feeding. There was no advantage in soaking for an extended time period. Implementing management changes in one stable (changing from straw bedding and hay feeding to wood shavings bedding and haylage feeding) significantly reduced mean and maximum background RDC in a neighbouring stable within a common airspace.)
Member:
ajudson1

Posted on Thursday, Sep 27, 2007 - 8:08 am:

Just read somewheres...TheHorse email? Or maybe Equus mag, that it wasn't necessary to soak the hay, just wet it right before feeding. I thought I understood from the article that it made a HUGE difference in the dust level.

The only think I've never been able to figure out is how we do this during the winter? Wouldn't it mean wetting small amounts through out the day?

Just thinking out loud here, I do have one horse who seems to get "heevy" although every time a vet checks her, she sounds fine.

Great comment about the molds.

Thanks for the update.
Member:
canderso

Posted on Thursday, Sep 27, 2007 - 8:12 am:

Dr. O,
Don't studies show that
- mould and particles of dust that get into the lower respiratory tract are the ones that do the damage (these are the small moulds and dust particles)
- the small moulds and particles of dust that can pass into the lower respiratory tract ARE reduced if hay is soaked 5 minutes
- that soaking past 5 minutes gives no further reduction in small mould/dust particles
- that soaking for more than 15 minutes leads to leaching of nutrients
?

Haylage can be a terrific product, if baled and handled correctly. But if not baled or handled correctly, isn't there a risk of botulism?
Moderator:
DrO

Posted on Thursday, Sep 27, 2007 - 5:07 pm:

Hello All,
I am not exactly sure I understand your question mark but most of your points are covered in more detail in the article on COPD. Since there seems to be a lot recently being published elsewhere on this subject that I believe to be misleading let me go over this in more detail.

Recently it has been published in layman journals that soaking hay will significantly reduce dust and that it only has to be lightly wetted or soaked to get the benefit. Whether explicitly stated or implied you come away with the feeling that you can soak dusty hay to make it safe to feed to horses as AngieJ implies. I think the problem with these articles is confusing "statistically significantly" with the more relevant "clinically significant".

The reason I think this is confused or downright wrong is the benefits of soaking hay flies in the face of both my experience and the results of large studies looking at this question (Dixon PM, Railton DI, McGorum BC. Equine pulmonary disease: a case control study of 300 referred cases. Part 1: examination techniques, diagnostic criteria and diagnoses. Equine Vet J 1995;27:416–421.) Also Dr Edward Robinson, a man who has studied COPD of horses for decades has stated as much in lectures I have attended. We all agree wetting or soaking hay will not reduce levels to make them tolerable to the large majority of horses suffering COPD.

Now if you take away from the message in the research that you can reduce the dust in the air of a barn, including hay and straw molds, by wetting the hay and this may help prevent horses from developing COPD I think you got it. But if you took from this it is OK to feed wetted down dusty (hay molds) hay to either healthy or COPD horses it ain't so.

Concerning the haylage issue, yes this is risk but as some of our european members have discussed it is all that is used in some parts of the world and that they do not see problems associated with its use. Corn has moldy corn poisoning, alfalfa: blister beetles, and any hay can contain poisonous weeds or carry botulism by way of small dead animals in it. There are no perfectly safe feeds and for the COPD horse without other alternatives, haylage may be a real blessing.
DrO
Member:
cathyb1

Posted on Monday, Oct 15, 2007 - 1:19 am:

I have a mare who has a strange cough. She puts her head down, almost groans, then coughs so hard that she has flatulance at the other end. She is not sick, no temperature, eating well, very healthy otherwise. The vet scoped her, and found she had pus around the epiglottis. Her lungs were clear. He put her on BromoTrimidine powder for 10 days, during which the cough disappeared. A few days after finishing this medication, the cough came back. I gave her Sputolysin (on the vet's advice) for another 5 days, which helped, although the cough didn't completely go. Now she is coughing fairly frequently.
I read the article about COPD and Summer Pasture COPD. My mare is stabled at night, out in her paddock during the day. We are in south Eastern Australia, on a farm. It is spring here, but we are in a DrOught (have been for a few years now), and although we had good autumn rains earlier in the year, everything is drying off rapidly, owing to hot, dusty, drying winds, and warm daily temperatures.
My mare's pasture is mainly what we call barley grass. It looks like barley, but smaller - obviously it is not really barley. It has a similar seed head. It is flowering at the moment. It has been quite dusty here.
She is stabled on wood shavings, although I notice over time that the woodshavings do break down to become a bit dusty. ( When I muck out, I remove the poo and the wet stuff, and put new shavings in. So the same (clean) shavings can be there for some time. Could it be the shavings that are making her cough? I feed her pellets and (our own) hay. Recently, as she was so fat after a spell, I was feeding her on barley straw (what is left over after we harvest the barley). It is not dusty, and smells fine, but it is nearly 12 months old. It makes my nose run, but then I am quite susceptible to hay fever myself! I have taken her off this, and put her on to a mixture of ryegrass and clover hay, not dusty, but almost 12 months old now. I am careful not to feed her musty or moldy hay - she would refuse to eat it anyway!
She is a big warmblood mare, which I use for dressage. She coughs when I first get on, then works fine, and coughs when I get off. Perhaps she is allergic to me!
Any ideas?
Moderator:
DrO

Posted on Wednesday, Oct 17, 2007 - 6:26 am:

Hello Cathy,
Rather than posting at the bottom of another discussion you need to move this post to a new discussion. Copy the text of your post and then click on Heaves & Chronic Obstructive Pulmonary Disease off the navigation bar at the top of this page.

At the bottom of the COPD page, underneath the existing discussions you will find the "Start New Discussion" button. Click it, create a descriptive title, and paste your text there. This should get you more and quicker responses. For more on this see Help & Information » Posting Guidelines or where did my post go?
DrO
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