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September 2013


with Pasture as the Primary Forage

Many horse owners have enthusiastically embraced the concept of keeping their horses barefoot, and have employed competent farriers or trimmers for physiologically appropriate hoofcare, or learnt to trim themselves.  Unfortunately for many, that initial enthusiasm has turned to disappointment as they struggle to achieve full foot comfort for their horses.  Despite some improvements their horses’ feet are still weak with thin soles that need some form of hoof protection when riding on hard or stony terrain.


Management and dietary advice often recommends restricting access to fresh pasture, in some cases no pasture grazing at all. Emphasis has also been put on feeding the horse low sugar and starch forage and hard feeds in an attempt to control deterioration in hoof structure and function.


It has been found that some horses with previously weak, sore feet have been able to acquire structurally strong feet purely by adopting a different dietary approach that optimizes magnesium intake, and minimizes elements that may reduce magnesium absorption.


Researcher and physician Dr Mildred Seelig  and others have documented that magnesium has depleted in agricultural soils globally, leading to a dietary magnesium deficit for many human populations that may be reflected in equine populations.   Fertilizers commonly used for commercial feed production rarely include magnesium, potentially progressively turning a magnesium deficit into a magnesium deficiency from the over-abundance of minerals such as potassium and calcium that can inhibit magnesium uptake in the horse.


Daily loss of magnesium from all factors needs to be taken into account when assessing dietary needs. Excess sugar and starch from feed or forage may increase urinary loss of magnesium.  Medical nutritionist Dr N Campbell-McBride has stated that humans need around 56 molecules of magnesium to metabolize a single molecule of sugar.   If this is also true of equines, then high-sugar feeds or pasture will increase the daily need for magnesium. Field experience indicates that horses ingesting high amounts of sugar from pasture are assisted by being fed increased amounts of supplemental magnesium.

Stress is known to cause increased loss of magnesium; this includes the stress of vigorous physical exercise, excitement, extremes of heat and cold, and mental or emotional anxiety.    For horses, this may include travel, training, competition, or changes in herd composition and hierarchy.   It has been frequently observed that high-anxiety horses benefit from increased dietary magnesium.


Genetics likely determines the metabolic response by each horse to the fluctuating amount of ingested dietary sugars and starch from pasture; similarly the degree of magnesium loss by reaction to stressors is also likely to vary between individual horses.    It is therefore likely to be impossible to accurately calculate how much magnesium is needed by any individual horse on a daily basis. Supplementing magnesium to gut tolerance appears to be a simple way to individualize requirements.


Although current nutritional paradigm dictates that ingesting magnesium far in excess of recommended ratios is harmful, anecdotal evidence from numerous horses in Australia and overseas does not support that view.  It is acknowledged that no formal controlled studies have been conducted to either prove or to disprove the hypothesis that increased levels of dietary magnesium may be effective in helping to build a strong, functional hoof in some horses.   However, the rapidly growing number of positive results from this novel approach suggests that further research is warranted.


The two detailed case histories presented (see the RORY and HOPPER Main Pages) are representative of many other horses with similar long-term soundness issues who have been able to grow strong feet with no need for protection on any terrain, and no, or very little, restriction to grazing.   Although the two horses featured are quite different, with very different problems, the dietary resolution to those difficulties has been identical.     Neither horse has ever been restricted from 24-hr grazing on plentiful pasture, mostly  with no need for hay; neither horse receives the strenuous exercise of regular work programs.  Both horses are fed a high magnesium, low calcium hard feed daily, and both are supplemented with high levels of magnesium chloride daily.

What about feed 'balancing'?

It should be noted that no attempt is made to 'balance' feeds to any predetermined Guideline.  For many horses, that approach has not succeeded in producing a strong, healthy hoof.   


The aged TB gelding, Rory, whose history is documented on this website, does not need hay as he grazes abundant pasture that has tested as low or deficient in zinc, copper and most elements except magnesium and potassium which are rated as high. Despite this his hoof integrity is dependent on daily supplementation with magnesium and chromium.    For the past 3 years, since being fed magnesium chloride, Rory has not been given any form of commercial or customised vitamin & mineral supplementation. Within a couple of months of commencing magnesium chloride Rory's chestnut coat colour deepened with a dappled sheen that does not fade through summer as it did in previous years.


One person who lived in a high-rainfall, subtropical region of Australia owned six horses with various hoof and lameness issues.   These horses could not tolerate grazing on the abundant kikuyu pasture so an extensive track system was installed.    Grazing was restricted to just a few hours from 2 am each morning.   The owner also constructed pea-gravel yards to keep the horses off wet ground for most of the day, and took an online equine nutrition course. Feeds and forage were analysed and a customised supplement protocol instigated to 'balance' the feed.   The horses did not significantly improve so the owner enlisted the help of a professional to check the anlysis.   After a year of this regime, all horses still had major hoof deformities and lameness problems.


Understandably, the owner was initially reluctant to eliminate excess calcium as that would 'unbalance' the feeds.   However, after 3 months of adding magnesium to the existing diet with no improvements, the owner was then brave enough to try eliminating all high-calcium feeds and supplements.    


All six horses started to improve very quickly and within a couple of months most had visible positive changes to their feet, some being able to walk on stones for the first time.   The horses continued to progress with most being able to graze without restriction. Two years later all horses are sound with rock-hard soles to their well-formed feet.


For a full explanation of the complexities of calcium and magnesium absorption and interaction, see the paper written by Nan Kathryn Fuchs, PhD:


'Magnesium: A Key to Calcium Absorption'


Go to the FEEDS - QUICK LOOK page to see the feeds and minerals that have been used to produce a strong, healthy hoof. Detailed information on the various minerals can be viewed on the MAGNESIUM and OTHER MINERALS pages and subpages.

Any queries that arise after reading everything on this site can be directed to:

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