Feeding for Respiratory Health this Winter

by Dr Tom Shurlock of British Horse Feeds 

It’s winter and our horses are snug in their stables, windows closed, a nice deep pile of straw for bedding, and a hay net full of what is probably second cut hay. There is a suspicion of a cough and you remember something similar last year. Of course it’s cold and wet outside and you’ve got the snuffles, so your horse probably has too, right?

Probably, but… is your horse heading towards middle age? Maybe he’s a Warmblood? Has he had a respiratory disease in the past? Did he have a cough during the driest part of the summer when he was outside?

If the answer to any of these questions is “yes”, then he may have Recurrent Airway Obstruction (RAO) – also known as chronic obstructive pulmonary disease (COPD), heaves, chronic bronchiolitis or bronchitis – or possibly summer pasture obstructive pulmonary disease (SPAOPD).

It sounds alarming and, according to various sources, may be present in up to 50% of all horses worldwide. It is also, thankfully, generally reversible and, once the causative factors are recognised and removed, fairly easy to eradicate. However if not addressed and in extreme cases can lead to:

  • Septic bronchitis 
  • Pneumonia 
  • Chronic interstitial diseases 
  • Neoplastic disease, including primary tumours of the respiratory tract or, more commonly, distant metastases

But let’s not dwell on the negatives, as we can do something – and it is maybe well to think about, even if our horse has no symptoms, as the cause is so common the potential is always there.

 

And the cause?

Dust. And spores. And fungi.

More precisely, small diameter organic and breathable dust and its potential to carry pollen, microbial spores and fungal toxins. These invasive particles irritate the linings of the airways causing inflammation and an influx of white blood cells; neutrophils, which invoke an immune response. The dust is associated with bedding and hay, although any dust in the stable can carry irritants.

Because this is a well-known route for potential airway problems in the horse, there has been plenty of advice on how best to reduce the problem. Most obvious is the need to clean down the stable when it is empty and to damp down any dust; a change of bedding is also recommended, where possible – wood shavings instead of straw for example. And the final piece of advice is to soak or even steam (to reduce mineral loss) the hay, or to provide alternative feeding.

Having said that, all hay is not bad. Dust potential of hay can vary considerably and increase from early to late cut, barn drying, cutting at 75% dry matter, big baling or hay getting wet between cutting and drying. The effect can be on breathable dust as well as viable spores. In the case of viable spores high density baling and late tossing, as well as rain after cutting, can all cause increases.

2012-FB-BAGThe source of the hay has an effect as well. Single species hays have different proportions of various dust types to each other and these are different from other forage types such as haylage and alfalfa pellets.

And finally the length of cut can have an influence. Short cut hay can have a high proportion if soil contamination, whilst long cut tends to be drier and therefore more brittle – generating more dust.

A medium cut hay, at greater than 75% dry matter and gathered before being rained upon will present a low dust/low spore product and should not exacerbate RAO.

Haylage would seem to be an obvious alternative to hay as it has extremely low dust and mycotoxin, due to its processing. However it does tend to have high pollen and moderate spores.

Ideally then, if you have access to grazing, then a winter outdoors will avoid all this dust. However, cold weather can cause cell inflammation and mucus production in the airways and so this can be as much a problem as being indoors!

So, with the dust potential for hay being totally confusing, how best to feed the horse in winter? As always, it’s mainly a matter of common sense. Those parameters that add to the problems of dust – spores, fungal toxins – are also not what we want from a nutritional point of view. Therefore hay that seems a bit musty, smells a bit off or has some bloom on it is not good for gut or throat. Beyond that we need to be a bit more choosy. Where possible use hay from the less mature grass – early cuts, hay that is medium cut, from rectangular rather than round bales. Think about the weather around cutting time. Was the cut grass able to dry quickly, or did it get wet? What dry matter is it?

Basically then a good quality hay, soaked to reduce dust, will provide a nutritionally sound forage base and a low irritant factor for the airways. However soaking for more than 30 minutes can significantly reduce sodium, potassium and phosphorus content. Conversely haylage with its inherently low dust levels should work as well although the high levels and range of pollens may increase the allergenic potential for some horses.

Beyond this we should be providing products that can partially replace these main forage sources, and so further reduce the irritants. Products such as beet pulp will naturally have low levels of pollen and fungal toxins, and the excessive washing during sugar extraction will further reduce contaminants. With Speedi-Beet the micronization part of the process will also knock out microbial spores making a clean product which, when fed soaked will be totally dust free. Pelleted alfalfa has been shown to have significantly less dust than hay, and when incorporated into a product such as Fibre-Beet that has a similar digestive profile to grass will certainly help .

So a soaked (30 minute) hay or haylage will give you a low dust product, and partial replacement with Speedi-Beet or Fibre-Beet will further reduce potential irritants, such as fungal toxins, spores and pollen, whilst maintaining a good level of nutrition over winter.

For more information please contact British Horse Feeds on 01765 680300 or visit www.britishhorsefeeds.com.

Author: Tom Shurlock

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