Thrush, WLD,
Abcesses, Laminitis, and Founder
By Vicki/ladywife
Feb 9, 2007
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Article List]
Uhuh, we’re getting all confused
now because we’re mixing up
which is which and what is
what. Thrush, WLD, Abscesses,
Laminitis, and Founder are all
distinct, individual things and
it is important to know the
difference between them since
the cause and treatment can be
vastly different too. Just
because it involves the foot,
calling it one thing when it is
another is like calling a donkey
a mule just because it has long
ears. Discussing these hoof
problems reminds me of what it
was like my first trip to
England, they spoke English, I
thought I spoke English, but we
definitely were not speaking the
same language with their
platters, lifts, trolleys,
lories, and biscuits.
Debbie, when you said when you
opened the foot it had a foul,
putrid odor, most likely it
wasn’t WLD. White Line Disease
is a fungus and/or bacterial
involvement in the White Line
damaging the adhesion of the
hoof wall to the laminae. It
starts at the toe, progresses to
the outside quarter, then the
inside quarter and eventually
the infection follows the bars
to reach the clefts. Laminitis
is an inflammation of the
laminae,
I am going to try to copy/paste
a very good explanation of
Laminitis and Founder from the
Wikipedia website but if it
doesn’t copy/paste to this post,
I highly recommend list members
go to the Wikipedia website and
read the article and perhaps
print it off for future
reference.
http://en.wikipedia.org/wiki/Laminitis
Here is the article:
Laminitis
is a disease of the sensitive
laminae of the
foot in a horse. The front
hooves are most commonly
affected, although the hind feet
are sometimes affected. Its name
means
inflammation of the laminae,
although inflammation is no
longer considered as the key
mechanism of the disease
process.
X-Ray
of a foot showing relative
rotation of the pedal bone and
the hoof capsule as well as some
sinking. While laminitis is
present, this is an example of
rotational founder
Foundering and sinking:
Rotation
and
sinking are two
possible consequences of a
single severe laminitic episode
or of repeated episodes. The
latter is less common and much
more severe.
Sinking results when there is a
cataclysmic failure of the
interdigitation
between the sensitive and
insensitive
laminae around the entire
perimeter of the hoof.
Apparently this event allows the
entire bony column, often
described by its most
distal bone, the third
phalanx (a.k.a. PIII, P3,
coffin bone, pedal bone, distal
phalanx) to sink within the
bottom of the hoof capsule. In
the
UK, this sequel is also
commonly called "founder", from
the nautical term "to sink". In
the
U.S.A., founder has come to
mean any chronic changes in the
structure of the foot. In some
texts, the term "founder" is now
used synonymously with
laminitis.
Rotation occurs when the damage
to the laminae is less severe
and it will show up mainly in
the toe area of the foot. One
possible reason for this is the
pull of the tendon attached to
the coffin bone, the deep flexor
tendon, literally pulling the
dorsal face of the coffin bone
away from the inside of the
hoofwall. It is also theorized
that the body weight of the
animal contributes to rotation
of the coffin bone. Rotation
results in an obvious
misalignment between PII (the
short pastern bone) and PIII
(the coffin bone). In some
cases, the rotation may also
result in the tip of PIII
penetrating the sole and
becoming exposed externally.
Depending upon the severity at
the onset of the pathology,
there may be no movement of the
pedal bone, rotation only,
sinking only or a combination of
both rotation and sinking, to
varying extents. It is generally
agreed that a severe "sinker"
warrants the gravest prognosis
and may, depending upon many
factors, including the quality
of after care, age of the horse,
diet and nutrition, skill,
knowledge and ability of the
attending veterinarian and
farrier(s), lead to
euthanasia of the patient.
Not all horses that experience
laminitis will founder but all
horses that founder will first
experience laminitis.
In laminitis cases, a clear
distinction must be made between
the acute situation, starting at
the onset of a laminitis attack
and a chronic situation. A
chronic situation can be either
stable or unstable. The
difference between acute,
chronic, stable and unstable is
of vital importance, when
choosing a treatment protocol.
Laminitis can be mechanical or
systemic, unilateral (on one
foot) or bilateral (on two feet)
or may also occur in all four
feet.
Systemic laminitis follows from
some metabolic disturbance
within the horse, from a
multitude of possible causes,
and results in the partial
dysfunction of the epidermal and
dermal laminae, which attach the
distal phalanx to the hoof wall.
With this dysfunction, the deep
digital flexor tendon (which
attaches to the semi-lunar crest
of the distal phalanx and serves
to flex the foot) is able to
pull the bone away from the
wall, instead of flexing the
foot. When the coffin bone is
pulled away from the hoofwall,
the remaining laminae will tear.
This may lead to abscesses,
within the hoof capsule, that
can be severe and very painful.
Also, a laminar wedge may form,
between the front of the hoof
wall and the pedal bone. This
laminar wedge may, in some
cases, prevent the proper
re-attachment (interdigitation)
of the laminae. Under certain
conditions and only after
consultation with an experienced
veterinarian and farrier team, a
dorsal hoof wall resection, to
remove this laminar wedge, may
be undertaken.
Systemic laminitis is usually
bilateral and is most common in
the front feet, although it
sometimes affects the hind feet.
Mechanical laminitis or
"mechanical founder" does not
start with laminitis or rotation
of the distal phalanx. Instead,
the wall is pulled away from the
bone or lost, as a result of
external influences. Mechanical
founder can occur when a horse
habitually paws, is ridden or
driven on hard surfaces or loses
laminar function, due to injury
or pathologies affecting the
wall.
Mechanical founder can be either
unilateral or bilateral and can
affect both front and hind feet.
It is important to note that,
once the distal phalanx rotates,
it is essential to de-rotate and
re-establish proper spatial
orientation of p3 within the
hoof capsule, to ensure the best
long-term prospects for the
horse. With correct trimming
and, as necessary, the
application of orthotics, one
can effect this re-orientation.
This attempt at re-orientation
may be less than one hundred per
cent effective, however.
Successful treatment for any
type of founder must necessarily
involve stabilization of the
bony column by some means.
Stabilization can take many
forms but most include trimming
the hoof to facilitate "break
over" and trimming the heels to
ensure frog pressure. While some
horses stabilize if left
barefooted, some veterinarians
believe that the most successful
methods of treating founder
involve positive stabilisation
of the distal phalanx, by
mechanical means, e.g., shoes,
pads, polymeric support, etc.
Steps taken to stabilize the
bony column gain maximum effect
when combined with steps that
will reduce the pulling force of
the flexor tendon attached to
the coffin bone, the deep flexor
tendon.
Causes of laminitis:
Many cases of laminitis are
caused by more than one factor
and are rather due to a
combination of causes.
Carbohydrate overload
If a horse is given grain in
excess or eats grass that is
under stress and has accumulated
excess
non-structural carbohydrates
(NSC, i.e.
sugars,
starch or
fructan), it may be unable
to digest all of the
carbohydrate in the
foregut. The excess then
moves on to the
hindgut and
ferments in the
cecum. The presence of this
fermenting carbohydrate in the
cecum causes proliferation of
lactic acid bacteria and an
increase in
acidity. This process kills
beneficial bacteria, which
ferment
fiber. The
endotoxins and
exotoxins may then be
absorbed into the bloodstream,
due to increased gut
permeability, caused by
irritation of the gut lining by
increased acidity. The
endotoxaemia results in impaired
circulation, particularly in the
feet. This results in laminitis.
Insulin resistance
Laminitis can also be caused by
insulin resistance in the
horse. Insulin resistant horses
tend to become
obese very easily and, even
when starved down, may have
abnormal
fat deposits in the neck,
shoulders, loin, above the eyes
and around the tail head, even
when the rest of the body
appears to be in normal
condition. The mechanism by
which laminitis associated with
insulin resistance occurs is not
understood but may be triggered
by
sugar and
starch in the diet of
susceptible individuals.
Ponies and breeds that
evolved in relatively harsh
environments, with only sparse
grass, tend to be more insulin
resistant, possibly as a
survival mechanism. Insulin
resistant animals may become
laminitic from only very small
amounts of grain or "high sugar"
grass. Slow adaptation to
pasture is not effective, as it
is with laminitis caused by
microbial population upsets.
Insulin resistant horses with
laminitis should be removed from
all green grass and be fed only
hay that is tested for Non
Structural Carbohydrates (sugar,
starch and fructan) and found to
be below 11% NSC on a dry matter
basis. Soaking hay underwater
may remove excess carbohydrates
and should be part of a
first-aid treatment for any
horse with laminitis associated
with obesity or abnormal fat
deposits. This can have the
effect of depleting the hay of
soluble minerals and vitamins,
however, so care with dietary
balance is important.
Nitrogen compound overload
Herbivores are equipped to deal
with a normal level of
potentially-toxic non-protein
nitrogen (NPN) compounds in
their forage. If, for any
reason, there is rapid upward
fluctuation in levels of these
compounds, for instance in lush
spring growth on artificially
fertilized lowland pasture, the
natural metabolic processes can
become overloaded, resulting in
liver disturbance and toxic
imbalance. For this reason, many
avoid using artificial nitrogen
fertilizer on horse pasture. If
clover is allowed to dominate
the pasture, this may also allow
excess nitrogen to accumulate in
forage, under stressful
conditions such as frost or
drought. Many weeds eaten by
horses are nitrate accumulators.
Direct ingestion of nitrate
fertilizer material can also
trigger laminitis, via a similar
mechanism.
Hard ground
Whenever possible, avoid working
horses on hard ground. This
includes concrete or gravel
roads. An indoor or outdoor
arena should be periodically
dragged with a rake, to loosen
the soil and to prevent it from
hardening. Hard surfaces
increase the concussion upon the
horse's feet. The greater and
more prolonged the concussion,
the more likely it is that the
horse will contract laminitis.
Lush pastures
When releasing horses back into
a pasture, after being kept
inside (typically during the
transition from winter stabling
to spring outdoor keeping), it
is important to re-introduce
them gradually. Feed horses
before turning them out and
limit the amount of time outside
(45 minutes to an hour at first,
gradually increasing the amount
of time) and decrease the amount
fed to them beforehand, as the
season progresses. If a horse
consumes too much lush pasture,
after a diet of dry hay, the
excess carbohydrate of grass can
be a shock to its digestive
system. If the horse is fed
beforehand, it will not eat as
much fresh grass when turned out
and will be less likely to
founder. It is also true that
ponies are much more susceptible
to this form of laminitis than
are larger horses.
Frosted grass
Some cases of laminitis have
occurred after ingestion of
frosted grass. The exact
mechanism for this has not been
explained but sudden imbalance
of the normal bowel flora can be
surmised, leading to endotoxin
production.
Freezing or overheating of the
feet
Cases of laminitis have been
observed following an equine
standing in extreme conditions
of cold, especially if there is
a depth of snow. Laminitis has
also followed prolonged heating
from incorrectly-applied
hot-shoeing. In either case, it
is possible to understand how
the circulation of the feet may
become adversely affected.
Cold exposure however has been
shown to have a protective
effect when horses are
experimentally exposed to CHO
overload. Feet placed in ice
slurries were less likely to
experience laminitis than
"un-iced" feet.[1]
Untreated infections
Infections, particularly where
caused by
bacteria, can cause release
of
endotoxins into the blood
stream, which may trigger
laminitis. A retained
placenta in a mare (see
below) is a notorious cause of
laminitis and founder.
Colic
Laminitis can sometimes develop
after a serious case of
colic, due to the release of
endotoxins into the
blood stream.
Lameness
Lameness causes a horse to favor
the injured leg, resulting in
uneven weight distribution. This
results in more stress on the
healthy legs and can result in
laminitis.
This may be the cause of the
laminitis which caused owners to
determine to put down former
Kentucky Derby winner,
Barbaro, on
January 29,
2007.
Cushing's disease
Cushing's disease is common
in older horses and ponies and
causes an increased
predisposition to laminitis.
Peripheral Cushing's disease
Peripheral Cushing's disease is
an area of much new research and
is increasingly believed to have
a major role in laminitis. It
involves many factors such as
cortisol metabolism and
insulin resistance. It has
some similarities to
type II diabetes in humans
(see also
insulin resistance,
described above).
Retained placenta
It is common practice, in
horse-breeding establishments,
to check by careful inspection
that the entire placenta has
been passed, after the birth of
a foal. It is known that mares
that retain the afterbirth can
founder, whether through
toxicity or bacterial fever or
both.
Drug reactions
Anecdotally there have been
reports of laminitis following
the administration of drugs,
especially in the case of
corticosteroids. The reaction
however may be an expression of
idiosyncrasy in a particular
patient as many horses receive
high dose glucocorticoid into
their joints without showing any
evidence of clinical laminitis.
No evidence exists to show the
mechanism by which
glucocorticoids trigger
laminitis in the horse.[2]
Exposure to agrichemicals
Even horses not considered to be
susceptible to laminitis can
become laminitic when exposed to
certain
agrichemicals. The most
commonly-experienced examples
are
herbicide and synthesized
nitrate fertilizer.
Symptoms of laminitis
-
Increased temperature of the
wall, sole and/or coronary
band of the foot.
-
A pounding pulse in the
digital palmar artery. (The
pulse is very faint or
undetectable in a cold
horse, readily evident after
hard exercise.)
-
Anxiety
-
Visible trembling
-
Increased vital signs and
body temperature
-
Sweating
-
Flared Nostrils
-
Walking very tenderly, as if
walking on egg shells
-
Repeated "easing" of
affected feet
-
The horse standing in a
"founder stance" (the horse
will attempt to decrease the
load on the affected feet).
If it has laminitis in the
front hooves, it will bring
its hindlegs underneath its
body and put its forelegs
out in front
-
Tendency to lie down,
whenever possible or, if
extreme, to remain lying
down.
Separation of the hoof wall
The destruction of the sensitive
laminae results in the hoof wall
becoming separated from the rest
of the hoof. Pus may leak out at
the white line or at the
coronary band.
Rotation of the third phalanx
The third phalanx, also known as
the coffin bone, rotates
downward. Normally, the front of
the third phalanx should be
parallel to the hoof wall and
its lower surface should be
roughly parallel to the ground
surface but, in laminitis, a
combination of forces (e.g., the
tension of the deep digital
flexor tendon and the weight of
the horse) allows the coffin
bone to rotate. The degree of
rotation may be determined by
severity of the initial attack
or by how soon laminitis is
detected and how soon actions
are taken to treat the horse.
Penetration of the third phalanx
through the sole
If rotation of the third phalanx
continues, its tip can
eventually penetrate the sole of
the foot. Penetration of the
sole is not fatal; many horses
have been returned to service by
aggressive treatment by a
veterinarian and farrier, but
the treatment is time-consuming,
difficult and expensive.
Treatment
There is no cure for a laminitic
episode and many go undetected.
However, a horse can live with
laminitis for many years. Rest
and corrective
shoeing, can help improve a
horse's condition. It may be
able to bear a rider or even
completely recover, if the
laminitis was not severe.
Successful treatment requires a
competent
farrier and
veterinarian and success is
not guaranteed. Alternative
therapies such as
herbal and
homeopathic medicine may aid
recovery but require expert
veterinary input.
Treatment via the NOLAN HOOF
PLATE
It s been found that the
Nolan Hoof Plate
stabilizes the hoof wall and
minimizes vibration throughout
the hoof. This typically results
in the immediate minimization of
pain felt by the horses that are
experiencing laminitis or
navicular syndrome, and can be
usually observed in foundered
horses as they usually change
conformation soon following
application of the plates.
Further, due to changes induced
by the hoof plate described
below, this allows for faster
healing of tissue and reduces or
eliminates continued tearing of
the lamina in horses that are
foundering .
http://www.hoofplates.com/hoofcare.htm
http://www.equilox.com/-Nolan-Hoof-Plates-C114.aspx
Complications from laminitis led
to the euthanization of
Barbaro, 2006 Kentucky Derby
winner, in 2007.
The barefoot movement
Studies on hoof health by
Dr. Hiltrud Strasser(Germany)
and
Jaime Jackson(U.S.)
suggest an alternative, more
optimistic view on laminitis,
which is supported by proponents
of the
barefoot horse movement.
This is a
holistic approach to the
disease, mainly based on pulling
shoes, proper hoof care and
trimming, proper diet and
movement.[3]
Cryotherapy is one way to
effectively treat laminitis in
the developmental stages.
Suggested reading
-
Adams
Lameness in Horses
Ted S. Stashak, D.V.M.
-
The Lame Horse
James R. Rooney, D.V.M.
-
25 Most Frequently Asked
Questions & Answers about
Laminitis and Founder
Burney Chapman, C.J.F., Bill
Moyers, D.V.M, et al
-
The Illustrated Veterinary
Encyclopedia for Horsemen
Equine Research Inc.
-
Veterinary Medications and
Treatments for Horsemen
Equine Research Inc.
-
Horse Owner's Veterinary
Handbook
James M. Giffin, M.D. and
Tom Gore, D.V.M.
-
Founder: Prevention & Cure
the Natural Way,
Jaime Jackson, Star Ridge
Company
-
Who's Afraid of Founder.
Laminitis Demystified:
Causes, Prevention and
Holistic Rehabilitation,
Hiltrud Strasser, The Naked
Hoof
-
Corrective Farriery, a
textbook of remedial
horseshoeing
Simon Curtis
-
The Principles of
Horseshoeing II and The
Principles of Horseshoeing
III
Dr. Doug Butler
-
Illustrated Atlas of
Clinical Equine Anatomy and
Common Disorders of the
Horse, Vol. One,
Ronald J. Riegel, Susan E.
Hakola
-
Understanding Laminitis,
Dr. R.F. Redden
-
Laminitis,
C.C. Pollit
http://pets.groups.yahoo.com/group/DonkeyMuleInfo/message/34923
