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Springtime – BEWARE of Laminitis!!

Laminitic Pony

Springtime – BEWARE of Laminitis!!

Experienced horse owners and carers understand the seriousness of Laminitis (commonly called Founder) and how quickly horses, in particular, ponies, can be affected.  Do not underestimate the need to be vigilant as “a gram of prevention is worth a kilo of cure” and when a horse has foundered, changes to the foot occur and these changes will affect the horse (in varying degrees) for the rest of it’s life and some horses are unable to be rehabilitated to soundness, to have feet which fit into the “normal” range.  Dr John Kohnke BVSc RDA has put this helpful information together to help identify and understand Laminitis and offer assistance to owners and carers.

Pictured left - the distinctive stance of a pony affected by Laminitis (founder)

Causes of Laminitis

Laminitis, or inflammation and fluid build-up within the hoof,is a painful and debilitating problem which can have a long term crippling result in horses, ponies and miniatures.

Although there are a number of causes of laminitis, and the more severe form of internal hoof collapse as in founder, it has been estimated that 80-85% of laminitis is seasonal and related to the excess consumption of fructan and soluble sugars, as well as nonstructural carbohydrates (NSCs) from good quality pasture and hay in grazing horses and ponies, especially those which are ‘good doers’ or ‘hooverers’. Many well fed horses and ponies have a metabolic related risk of developing laminitis if they are overweight with underlying Equine Metabolic Syndrome (EMS) or Insulin Resistance (IR) as they age over 10-12 years of age or develop Cushing’s Disease in old age.

The causes and complications of EMS and Cushing’s Diseaseare discussed in Fact the Kohnke's Own Sheet C3.

Other less common causes include severe  toxic founder due to infection from hoof abscesses; retained membranes in a newly foaled mare or septicaemia from colic or travel sickness;  stress founder resulting from dehydration and stress when standing for long periods during transport;  concussion founder when worked
at speed on a hard surface and  weight transfer founder due to excessive weight bearing on a ‘good’ limb for more than 9-10 minutes at a time to take the weight off an adjacent, severely painful injured limb as result of a bone fracture, a severe tendon injury or a wound, such as deep wire cut from a fence.

The Most Common Underlying Cause - Early Spring Founder

Winter grasses that are boosted in growth by warmer, early and wet Spring conditions after rain or irrigation , with cool nights and warm days, often become lush and highly productive. Lush pasture, especially ryegrass, phalaris and fescue dominant pastures, are considered high risk pastures, as well as succulent, rapidly growing clover in pastures  in early Spring.

These grasses are able to accumulate large amounts of nonstructural carbohydrates (NSCs) in the form of fructans and other simple sugars. Under cold overnight and early morning conditions, these sugars are not transferred into the plant stems for growth.

Some of these simple sugars in the succulent shoots and leaves are digested in the stomach and small intestine to release glucose, which then triggers an increase in the level of circulating insulin, which is already high in an animal suffering from Insulin Resistance. In turn, the elevated insulin acts directly to trigger the onset of aminitis and devitalisation of the hoof lamellae. Any excess sugars may also be overloaded into the hindgut, with secondary production of lactic acid, a non-absorbable, non-metabolisable acid, which can accumulate in the hindgut digestive mass.

This acts tolower the hindgut pH and suppress normal fermentation, with the death of large numbers of hindgut microbes and damage to the barrier function of the hindgut lining. A toxin is also produced by the lactic acid producing bacteria and other dying bacteria, which when absorbed into the blood stream, circulates to the hooves to interfere with the blood supply to the lamellae and devitalise the basement membrane attachments. The weakened lamellae attachments can be torn apart by the continuous downward rotational ‘pull’ of the deep flexor tendon attached under the pedal bone, leading to founder.

  Cycle of Spring Founder  

“Founderguard” acts to suppress harmful bacterial proliferation.
“Equishure” buffers excess hindgut acid.

Late Spring and Autumn Founder

Pastures which reshoot after rain, grazing or after being slashed
under warm, wet conditions, can store large amounts of NSC
carbohydrates, which can be digested in part in the small intestine
to cause “spring fever” or excitement, as well as trigger an insulin
surge, leading to laminitis, especially in animals bordering on Insulin
Resistance (IR).

Handy Hint 1
A heavy frost can cause the release of sugars stored in
severely ‘burnt’ pasture grasses in early spring, or when pastures
are sprayed to control broadleaf weeds, making the grasses ‘sweeter’
and more palatable to grazing horses, with a risk of laminitis in EMS
affected horses and ponies. Even dried grass dying off under drought
conditions without regular rainfall to leach out sugars from the
‘standing hay’, poses a risk to over-weight and ‘cresty’ horses
and ponies grazing the dried grass.

Handy Hint 2
Laminitis is most likely to occur in ‘cresty’, overweight horses and ponies suffering from underlying Equine Metabolic Syndrome (EMS) and pre-Cushing’s Disease with a glucose intolerance and insulin resistance similar to Type II diabetes. It does not take
very large amounts, even an overnight ‘binge’ on high “sugar” pastures, to trigger a laminitic episode in ‘cresty’ and overweight EMS horses and ponies. Susceptible horses and ponies with underlying EMS are on are on a virtual ’tight-rope’ in balancing NSC intake from grasses during periods of lush pasture growth or when
they have unrestricted access to grazing on high risk pastures.

  Cycle of Summer Founder  

Regular daily monitoring for a ‘hardening of a ‘cresty’ neck which heralds glucose intolerance and a surge in insulin, can indicate an impending laminitic episode.

Careful grazing management during the high-risk periods is essential to avoid the onset of Laminitis and repeated episodes later in the horse’s life. 

  Laminitic Pony
 

Above - The typical stance of a fat pony with Laminitis. In horses the symptoms can be more difficult to identify, but the effects are just as serious.

 

John KohnkeSaddleworld thanks Dr John Kohnke for this valuable information and reminds all horse owners that Springtime is the season for Laminitis and every year horses and ponies are at risk.  It is important that owners take this threat very seriously and take preventative measures to avoid Laminitis. 

This is an investment in maintaining the horse’s (pony’s) optimum hoof-health which will enable the best possible ease of movement.  Other foot conditions which come about after a bout of Laminitis are similarly avoided.

Pictured above right - Dr John Kohnke

Kohnke's OwnMore Horse Health and Nutrition information can be found at ...
http://www.kohnkesown.com
You can e-mail  info@kohnkesown.com or call 1800 112 227

Your local Saddleworld store carries Kohnke’s Own products and can assist you with more information.  Go to www.saddleworld.com.au for your nearest store.