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Making
the Connection It is common knowledge that "fat" horses are prone to founder. But, why is that? At the top of our list you noticed that a cresty neck, fat pads, and overweight or "easy keeper" were all key factors. One or all of these are often symptoms of an underlying metabolic disorder. The metabolic issues that are related to laminitis are Cushings (a tumor on the pituitary gland), insulin resistance (similar to Type II diabetes in humans), carbohydrate intolerance, and other hormonal imbalances that remain to be identified. In the case of the majority of metabolic issues, there is a direct relationship to a form of carbohydrate (sugar and starches) sensitivity While most horses do not appear to have metabolic issues, there are some that are just genetically different and most likely have a predisposition for an intolerance to high intakes of carbohydrates. These types are generally labeled "easy keepers" and are often the ones that suffer laminitis from spring grass or overindulge of feed. The term "thrifty gene" has been associated with these horses. It is not a dysfunction of the system, but rather genetic hardwiring for survival. It is reasoned that these horses are attuned to surviving in times of drought, winter and other situations of inadequate food by relying on limited amounts of carbohydrates and having a natural tendency to accumulate fat stores to see them through times of need.
The second primary grouping of risk factors is related to toxic reactions. Allergies to drugs, inoculations, and certain plants can cause a reaction severe enough to result in laminitis. Similar reactions occur in cases where toxins are ingested in the form of chemical contaminants (high nitrate concentrates in water sources, pesticide run-off, and herbicides sprayed on plants along pasture fences) or poisonous plants. Spring "overload" in the form of inoculations coupled with slight pollen allergies, lush grass and/or hormonal changes may contribute to laminitis. Retained placentas and laminitis that seems related to other diseases are also similar in nature to allergic or toxic reactions. Systemic conditions set up by the body to counteract the effects of the toxins released during illness or when a placenta is retained often set off a series of events that trigger laminitis. The final grouping of factors are those related to what is commonly called "road founder". More correctly termed mechanical founder, the conditions for laminitis are set up by the health and integrity of the foot and the amount of trauma induced. Mechanical founder is often misdiagnosed as it is the "catch all" for "unknown" causes of laminitis. It is generally the easiest to deal with because the horse rarely has a repeat occurrence. Treatment is generally restoring the integrity of the feet and avoiding a repeat of the causative trauma. Extended Treatment Your veterinary should
take x-rays of the feet to determine the amount of rotation or sinking. They
then Recent research indicates that many founder cases (especially those that are chronic) suffer from an underlying metabolic disorder. Some of the less severe cases have been successfully treated with the addition of magnesium to their diet. Supplementary magnesium is often needed in areas east of the Mississippi River because of a soil or plant deficiency. Magnesium is essential in cell wall health and neuron function. It is also needed to keep insulin receptors functioning properly. Additionally, magnesium is an acid buffer that helps reduce excess stomach acid and acidosis. Recent research indicates that excess acid in the digestive track seems to be more common than was previously thought. Studies revealed that a high percentage of horses have ulcers. It is believed that many foals are even born with ulcers. Feeding large amounts of whole grains or concentrates can result in excess acid and possibly acidosis which may trigger laminitis. Horses are designed to digest concentrates in the stomach and small intestine, while forage passes to the large intestine to be broken down by microbial fermentation. The high levels of carbohydrates (sugars and starches) in concentrates are supposed to be converted and absorbed in the acid of the foregut. When they are forced to the large intestine (by being consumed in large volumes (more than 5 - 6 quarts per meal) or large amounts are consumed over the course of the day (such as while grazing lush spring pasture), it sets up an acid reaction in the hindgut that kills off the beneficial bacteria that helps with digestion. This rapid die-off results in the release of endotoxins that prompt a systemic enzymatic reaction that effects the feet. It appears that some horses simply have an issue with carbohydrates in the form of sugars and starches and are prone to excess acid or acidosis. Therefore it is always wise to provide forage as the majority of your horse's meals. It is recommended that upper limits of concentrates be less than 30% of the total diet. However, the safe limit for horses that may have a propensity to laminitis is suggested at 20% or less. It is also recommended that these cases be fed alternative forages as opposed to grains and commercial concentrates. Beet pulp and forage pellets or cubes may be substituted to add extra calories. For horses that do not have access to or are prohibited from grazing, a source of omeg-3 fatty acids should be provided. Flax (seed, meal or oil) or fish oil are good sources of these essential fatty acids. Essential fatty acids also provide support for repairing and growing hoof tissues. Many times it is necessary to confine horses prone to founder to dry lots or limit grass intake. Often, grazing muzzles help limit intake without the need for confinement. However, some horses learn to take them off and must be carefully monitored. Other methods are to provide limited grazing time or limited areas for grazing that have little or poor quality grass. Additionally, feeding hay before turnout will help the horse feel full and therefore encourage self-limitation of grazing. Summary This week's tip has provided you with some of the basics, but laminitis cases can be very complex. There is not "one cure fixes all". You may need to consult with a veterinary and/or farrier that have a variety of successful treatments available. A carefully chosen team and knowledgeable owner is the best chance your horse has of optimal recovery from founder. |
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© Sue Baker, Russo's Tack Shack 2004 |
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