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Bed-Down Info - The Science Page
This
page contains science based information relating to Bed-Down. View
this page for the following articles:
Chronic
Obstructive Pulmonary Disease (C.O.P.D) in Horses
by Anna Rush MRCVS
The
Horse's Respiratory System and Dust Inhalation in Easy to Follow Bullet
Points
By Sophie Flux (BSc Hons), Bed-Down
The
Bedding Guide
By Sophie Flux (BSc Hons), Bed-Down
ARTICLE
1
Chronic
Obstructive Pulmonary Disease (C.O.P.D) in Horses
by Anna Rush MRCVS
1)
What is COPD?
The easiest analogy is to compare COPD with asthma, where the airways
react to airborne allergens. This reaction usually causes a narrowing
and stiffening of the airways making it difficult to breathe comfortably,
and causing a cough. Initially breathing difficulties only occur when
the allergen is present, but eventually the airways become damaged by
repeated inflammation and become chronically narrowed resulting in a permanent
reduction in the lung capacity.
2)
What causes COPD?
Horses are designed to live in the open plain, so keeping them in a stable
is going very much against what their bodies were designed to cope with.
When a horse is stabled it is exposed to a far higher concentration of
airborne particles than it would encounter in the field, this puts a strain
on the house keeping mechanisms of the lungs and can eventually cause
permanent damage – exacerbating the problem. Dust from the environment,
feed, bedding material and the horse itself (ie dead skin cells) builds
up in the atmosphere and is inhaled, the smaller the particle the further
into the lung it is carried. COPD is an allergic response to these particles.
3)
How are the airways protected?
•
Filtration – this
occurs in the upper airways ie nose and trachea, where the velocity of
the inhaled particle causes it to impact the walls of the airway where
it becomes adhered to the mucus and cannot progress further.
• ii.
Mucus – this is
the main defence system of the airways, it is produced as far as the
bronchioles, but not in the alveoli. Most particles are captured by
the sticky mucus and carried up out of the airways on the muco-cilliary
elevator (an active mechanism) to the throat and then swallowed. These
cilia are damaged by respiratory disease and make the animal prone to
further disease. When a horse is in a “dirty” environment the production
of mucus increases, this can lead to clogging up of the smaller airways,
ie the alveoli where gas exchange takes place, by the thick particle
containing mucus.
4)
What are the symptoms of COPD?
The symptoms seen depend largely on how far the disease has progressed,
initially there may be a reduced level of fitness and a chronic cough
particularly when starting exercise. As the condition becomes more severe
the horse will breath more frequently, appearing to be out of breath even
when not exercising. At its most severe a double expiratory effort will
be seen, this means that the horse cannot breath out passively in the
normal way and needs to use its abdominal muscles to exhale – this is
when you can see heave lines on the belly. These symptoms often become
worse in the presence of allergens ie when the horse is stabled.
5)
What causes these symptoms?
The horse experiences difficulty breathing because of a combination of
effects. The build up of excessive mucus in the lower airways blocks the
tiny alveoli, combined with inflammation causing the airways to narrow
the gaps further. This means that there is more resistance against air
being inhaled or exhaled, which requires more muscular effort which is
tiring. The energy that would normally be used in exercise is used simply
to supply the body with sufficient oxygen, and because less air can be
drawn in there is less oxygen available to the muscles so they tire more
quickly. This leads to exercise intolerance, the build up of mucus causes
the cough which is often one of the first symptoms to be recognised. Eventually
the airways loose their elasticity which means that even more effort is
required to fill or empty the lungs, causing the increased rate of breathing
and the heave lines.
6)
How can COPD be treated?
The first step is to remove, as far as possible, any allergens from the
air that the horse is breathing. This is usually achieved by stable management,
which will be discussed later, or by simply turning the horse out all
the time (this is not appropriate when your horse is allergic to pollens).
If this does not relieve the symptoms then always consult your vet. Initially
your horse will probably be given antibiotics to control any secondary
bacterial infection caused by the accumulation of mucus, and a broncho-dilator
to open the airways up and make it easier for your horse to draw breath.
Mucolytics, which thin the mucus and make it easier for it to be removed
by the cilia can also be employed. If this is not successful then steroid
inhalers, similar to those used in human medicine may be used, but these
are rarely employed as they are poorly tolerated by the patient. Steroids
can also be given by long acting injection, but the relief is not as rapid
as it is when given by inhaler, so is used for chronic cases.
7)
What steps need to be taken in stable management?
The most important factor to control in the stable of a horse with COPD
is the quality of the air that horse is breathing while it is stabled.
Dust comes from 4 main sources, the feed, the bedding, the environment
and the horse.
•
Feed - hay is a major
source of fungal spores, which are the most common allergen. Always buy
good quality hay, or your own breathing may also be affected (Farmers
Lung – a disease caused by fungal spores in humans) and soak it down approximately
20 minutes before feeding it. Any longer than this and the nutrients will
start to leach out, if you leave it to dry before feeding it then the
dust will be loose again. Treated hays and similar grass based products
are often dust extracted or have additions such as molasses which reduce
the dust content to almost nil, however care must be taken with these
products that they do not “go off” and become mouldy. In addition it is
beneficial to feed the horse on the ground as this decreases the number
of particles inhaled and facilitates mucus draining out of the airways.
• ii.
Bedding – straw
is probably the most common bedding material used for horses, due to
a combination of availability, tradition and price. Unfortunately, poor
quality straw can do more harm to your horse than poor quality hay.
Fungal spores in poor quality straw are stirred up into the atmosphere
every time the horse moves around in the stable, and during mucking
out. Deep litter beds, although often cost effective, provide the ideal
environment for fungal proliferation – warm and wet - and should be
avoided. This is true with any bedding material, not just straw. Dust
extracted straw or wood shavings are the bedding of choice as they are
easiest to manage and, if good quality products are used, often include
agents to minimise fungal growth and dust production. The levels of
dust are significantly lower than traditional bedding material.
• iii.
Ventilation – no
environment can be entirely dust free, therefore good ventilation is
vital to keep a steady stream of fresh air (but not a draught) flowing
through the stable. Signs of poor ventilation include dust visible floating
on sunlight and dust laden cobwebs on the walls and in the eaves, you
may also notice a slight difficulty breathing if you suffer from hayfever.
Before any physical alterations are made to the stable it is important
to take advice and plan carefully to prevent a stuffy stable becoming
a draughty stable and giving your horse no real relief.
8)
What is the future once COPD has been diagnosed?
COPD is usually diagnosed in older, often retired horses where a lifetime
of stabling catches up with them. In these cases high levels of athletic
performance are not required so the condition can be largely managed by
close attention to detail in the stable and turning the horse out to grass
where possible, intermittent medication may be required - usually seasonally
based.
In
younger horses there may by a permanent decrease in the athletic ability
of the horse, although due to the seasonal nature of the disease in the
early stages a reasonable level of fitness may be maintained. This will
again require fastidious attention to detail in the stable to minimise
exposure to dust, careful exercise when the horse is apparently unaffected
and medication where necessary to alleviate distress.
ARTICLE
2
The
Horse's Respiratory System and Dust Inhalation in Easy to Follow Bullet
Points
By Sophie Flux (BSc Hons ) Bed-Down
Importance
of the Respiratory System:
- Life support
system.
- Horses rely on
the respiratory system more than any other domestic animal.
- Lungs of a mature
horse are exceptionally important, with a surface area equivalent to
the size of all Wimbledon courts.
- When a horse
is galloping/cantering its breathing and its stride pattern are in time
with each other. E.g. Badminton horses take over 140-150 strides per
minute; this indicated that horses at this level have less that 0.5
seconds to take each complete breath.
- Compared to other
fodder eating animals (cows and sheep) the horse has significantly more
strain on its body and lungs.
- Horses only have
the ability to breath through their nose. Therefore any discharge from
the nasal cavities has a significant affect on the performance of the
horse.
Respiratory
Diseases in Horses:
- Diseases: Strangles,
Influenza, Pneumonia, Whistling, Roaring, Coughs.
- COPD is also
a common respiratory tract infection.
- Viral infections
lead to a loss of cilia (cilia removes particulate matter). This then
allows airborne contaminants to enter the lungs and reach sensitive
tissues.
- Loss of cilia
therefore increases the amount of fungal spores inhaled.
- Once infected,
environmental pollutants often prolong recovery.
- Once a horse
has suffered from a respiratory disease it is prone to relapses.
- Solutions are,
vaccination and stable management.
Treatment
And Prevention:
- Pharmaceuticals:
- Agents
speed up recovery.
- A
common example is Ventipulmin, which opens closed airways.
- Mucolytics
clears airways of mucus plugs.
- Environment:
- This
is to prevent the source of the problem. i.e. to keep the causative
agents below the level which induces disease.
- The
critical level is known as the Threshold Limiting Value (TVL). Unfortunately
this level is unknown for fungal spores.
- Therefore
you have to minimize the exposure to the contaminants “Dust”
- There
are 2 main sources of fungal spores.
a) Horse Feed
b) Bedding Materials
- Feed:
- Quality
of hay is exceptionally important, and is one of the most common
sources of fungal spores.
- Poor
quality hay is the largest problem; as it dries it produces spores
and seeds the bedding.
- Many
people soak hay, which reduces inhalation of dust particles but
the fungal spores, are ingested along with the toxins they produce.
- Solution:
- Cleaners: Vacuum and steam hay.
- Use treated fodder. E.g. silage and haylage.
- Treated chaffed hay and straw is excellent at minimizing respiratory
disease. Unfortunately the nutrition value of
this product is exceptionally low.
- Bedding:
- Why
people use straw:
- Abundance
- Cost
- Ease of storage and disposal.
- Light Bedding (weight and colour).
- Old
straw bedding: Long, cleaned, combed, wheat straw. Uncrushed, good
warm bedding.
- Today's
Straw: Stems are short and crushed, chemical residues, large quantity
of fungal spores.
- Even
the cleanest modern straw contains more fungal spores than alternative
bedding products.
- Fungal
spore counts increase if the stable is poorly ventilated and moulding
occurs.
- Deep
Litter management causes a build up of noxious gases, ammonia, infectious
bacteria, and larvae of gastro-intestinal parasites.
- Ventilation
- Exceptionally
important, you need 6-8 changes per hour.
- Good
ventilation helps to overcome condensation, prevent moulding, and
minimize levels of all airborne contaminants
- Sunlight
(skylights) enables sunlight to penetrate the stable and kill bacteria
and viruses.
- Dust
Free Fodder
- Micro-organisms
are the cause of the problem.
- Viruses.
- Bacteria.
- Fungal Spores.
- Sources
of these organisms are hay, straw and the forage mite.
- Horse-hage
is recommended by veterinary surgeons for horses with coughs or
fully blown COPD (Chronic obstructive pulmonary disease). It is
also highly digestible and has high energy levels and vitamin levels.
- Solutions
- Correct
Ventilation
- Stable
Hygiene
- Bedding
- Feed
Material
ARTICLE
3
The Bedding Guide
By Sophie Flux (BSc Hons), Bed-Down
“ What is the best type
of bedding to use for my horse?” is a question frequently asked
nowadays due to the large amount of choice. Before the days of dust extraction,
peat, long straw (wheat, barley, oat) or wood shavings taken from the
carpenter’s floor were used in stables. However, today, there are
many types of different bedding, to add to the traditional ones, made
from hemp, flax, paper, cardboard, crushed pallet wood, seaweed and even
the Yellow Pages! All of these varieties can be found in our local retailers
and wholesalers. Therefore, due to this mammoth choice, I have come up
with a method to hopefully allow you to make the correct bedding choice
for you, using ‘The Bedding Guide’!
To use ‘The Bedding Guide’
you should follow each step below. Initially you should choose a bedding
type e.g. Brand X. Then at each Step you should ask ‘Does the bedding
I am considering meet this point?’ If it does, you should move on
to the next step, if it does not, you should go back to the start and
begin with another bedding type.
Step1:
‘ What do we need the bedding for?’
Generally bedding is used in stables to prevent draughts, to provide warmth,
to prevent injury when the horse lies down and to assist drainage. The
bedding you are considering must do all of these points in your stable
otherwise the horse might as well stand on a concrete floor!
Step 2:
‘ What makes a good bedding?’
A good bedding should be soft, dry, warm, non-toxic if eaten, non- toxic
to the skin, absorbent, provides good drainage, is low in micro-organisms,
is relatively dust free and easily disposable.
To decide if a bedding is soft,
squeeze it in your hand because only then will you know if it is suitably
soft for your horse. Most beddings are dry initially but then can become
wet very quickly in the stable and start causing problems, hemp bedding
is ‘activated’ by a sprinkling of water to the new bed, if
you have a horse which does not do well in moist conditions perhaps this
dampening will not be suitable for you. Some treatments of beddings have
the potential to cause skin irritation, so if you have a very sensitive
horse try to choose a bedding with no added chemicals. Smaller particle
beddings such as shavings are generally more absorbent than straw. However
straw is one of the best beddings for drainage, as it allows the wet to
run through and along the straw shafts. Good drainage means a drier bed,
and good absorbency means that you can lift out the wet when mucking out.
A drier bed means that there is less urine and therefore ammonia and microorganisms
growing in your stable. A combination of ‘the best of both worlds’
of absorbency and drainage is found in mixture bedding made from chopped
straw and shavings. Crop based beddings e.g. straw, flax or hemp have
a generally higher micro-organism count than wood based ones, but anti-viral
and mould suppressant treatments used in some beddings will reduce the
counts dramatically. Dust reduced beddings are important, as discussed
later, and the greater the reduction in dust the better. (Please note
that there are many claims on a ‘dust-free bedding’, but remember
this does not exist, no bedding is dust free, as soon as you lift a bale
you will create friction, which will produce dust particles, so don’t
be fooled!). Disposal of crop based bedding is easier than wood based
products as straw decomposes far more rapidly and farmers and gardeners
prefer to spread straw on their land.
Step 3:
‘ Is it suitable for my horse’s:
a) Lungs?’
Horses are designed to live in the open plain, so keeping them in a stable
is going very much against what their lungs were designed to cope with.
Recurrent Airway Obstruction (RAO) (or COPD as it used to be called) is
a disease associated with an allergic response to microorganisms and dust
particles found in the stable environment. RAO is suffered by a number
of horses due to stabling and anybody who has a horse with RAO realises
how important it is to prevent exacerbating the problem and anyone whose
horse does not suffer from it, should be aware that their horse could
suffer from it at any point in time! Therefore reducing the amount of
respirable dust as much as possible, using dust reduced bedding, will
help prevent the onset of this debilitating disease.
If you have a horse, which
suffers severely with RAO, I suggest a non-crop based bedding e.g. shavings
or paper, as microorganisms found in straw, hemp or flax could bring on
an attack. Remember also to use dust reduced forage e.g. Haylage and to
keep the stable well ventilated.
b) Stomach?’
Horses that are stabled for many hours of the day are more likely to eat
their bedding, this is thought to be due to boredom and hunger. As bedding
is usually indigestible, the eating of it can cause an impaction of the
gut e.g. colic. Therefore, the less palatable the bedding, the less chance
of the horse developing colic. Unfortunately crop based beddings e.g.
straw and flax are more likely to cause this problem, however some beddings
are now treated with unappetisers to prevent the horses nibbling!
c) Movement?’
Horses, which are suffering from acute lameness, find it hard to bend
their legs in long straw, as the stalks can wrap around the lower leg
and make the horse struggle even more when moving. Smaller particles from
beddings such as shavings or paper can impact in the foot, which could
exacerbate foot problems e.g. Thrush. Smaller particles can also be unhelpful
to a horse that lies down frequently as the shuffling of the body can
cause the bed to move from under the horse and so it ends up lying on
the stable floor. Smaller particles are therefore not recommended for
foaling either. I have also seen sharp particles stick to a horse’s
eyeball before, which can be distressing for owner and horse, a problem
unlikely to occur with long straw.
d) Mind?’
The horse’s mental health is being considered more and more nowadays
and I found it interesting to read in a scientific paper that a group
of Thoroughbreds were tested to see which type of bedding they preferred.
The horses were given the choices of long straw, shavings and paper. The
conclusion was that the “horses clearly showed a preference for
straw bedding” and that the straw allowed “the expression
of a wider number of motivationally significant activities”. Therefore
suggesting that a straw based bedding allows our horses to be happier
in the stable.
Step 4:
Is it the most healthiest management system for my horse?
It is not just the type of bedding which is important for the horse’s
lungs, but also the management regime. Fungal spores in poor quality bedding
are stirred up into the atmosphere every time the horse moves around in
the stable, and during mucking out, so always take your horse out of the
stable when cleaning the stable or grooming the horse. Deep litter beds,
although often cost effective, provide the ideal environment for fungal
proliferation – warm and wet - and should be avoided. This is true
with any bedding material, not just straw.
Step 5:
Is it practical for me?
Disposal of the bedding is important, as removing muckheaps
can be very costly. Many wood based beddings take a long time to decompose
unlike crop based ones.
Mucking out can take anything
from 10 minutes to half an hour depending on how easy the bedding is to
separate clean from soiled. Paper and cardboard are renowned for their
difficulty and long straw takes a relatively longer time to clean than
smaller particle beddings. Crushed pallet wood beddings are less likely
to stick to the horse’s coat unlike shavings, which like to linger
in a horses tail and so it can take longer to groom.
Step 6:
Can I afford it?
Find out from your nearest retailer how much it is to have the
bedding delivered to your stables, as generally it makes economic sense
to have a bulk load delivered rather than buying a few at a time from
the shop. Work out how much it will be to use per week and remember to
add on the cost of disposal as bulky slow decomposing muck could be very
expensive to remove.
Obviously, each horse owners
needs are different and therefore each outcome will be different too.
Remember to think over all points of the beddings you are considering,
as all beddings have their advantages and disadvantages, which only you
can weigh up in your mind. Inexpensive bedding, may initially seem to
be a wise economic move but the bedding may harbour high levels of mould
spores and dust that could cost you expensive vet bills, so creating a
false economy. Basically, we want our horses to be comfortable and to
be relaxed in the stable, so think carefully and happy choosing.
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