In order to stay healthy we must consume the right
balance of vitamins and minerals in our diet, the same is true of the horse,
and while we worry about certain components like Calcium we often overlook and
underestimate the importance of other minerals. Magnesium is a prime example;
it is an essential trace mineral, found in all organisms, in every cell. As
research and understanding increase, the importance of correct magnesium
balance appears to be more and more significant. Deficiency directly causes a variety
of physiological and behavioral symptoms and is associated with a vast array
of disorders and is therefore widely used therapeutically in human medicine. In
terms of behavioral problems, both with equines and other species, it is the
role magnesium plays in excitability nerve stimulation and its association with
stress mechanisms including the release of adrenaline, which are of most
importance.
In humans a number of conditions have been associated
with magnesium deficiency including restless leg syndrome and muscle twitches,
muscle cramps and aches, migraines and headaches, attention deficit disorder,
anxiety, an array of heart problems, hypertension, schizophrenia, depression,
asthma, autism, diabetes, osteoporosis, peptic ulcers etc. There are often
multiple associations between disorders and research is increasingly showing
that stress and magnesium deficiency are a common link. One study observed
mineral abnormalities in children suffering from attention deficit hyperactivity
disorder and found that an imbalance in magnesium was consistently and markedly
the most pronounced, treating these children with magnesium supplementation
significantly reduced hyperactivity. This is just one example of many cases in
which magnesium has been used successfully to reduce behavioral problems,
particularly in excitable patients.
This research is all well and good but how does it
apply to your horse?
The answer is that the underlying mechanisms are the
same and they manifest themselves in similar ways. Muscle tension,
hypersensitivity, exaggerated response to stimuli; aggression and laminitis are
all common problems which magnesium supplementation is used to help. There are
several interlinked mechanisms associated with Mg deficiency that contribute to
these problems.
Magnesium deficiency causes the release of adrenaline
and other stress hormones that cause anxiety. Interestingly, research shows a
negative effect where magnesium deficiency cannot only cause stress but being
exposed to stress further depletes magnesium levels thus worsening the
situation. The release of adrenaline is normally a protective measure that
equips the horse for fight or flight. Although this survival response is
extremely helpful in the wild, the over ready state is not only the route of
many behavioral problems but also has many biological repercussions and it is
not healthy for it to be maintained too frequently or for long
periods. The domestic horse is exposed to an unnaturally high level of stress
stimuli and yet the adrenaline response is of no use, and being unable to
respond effectively to stress is itself a cause of further anxiety. Causes of
stress and magnesium depletion can be both physical and emotional, examples
include: cold weather, strenuous exercise, injury, pain, excitement,
depression, isolation, noise, fear, confinement, hunger etc.
Normally, a signal is transmitted in response to a
stimulus by an influx of ions along a nerve. Magnesium is needed to control
this influx and without sufficient amounts ions can flow more freely into the
nerves making them overly sensitive. Thus, low levels of magnesium result in
hyper-excitability of nerves and muscles. Accompanying this is a rise in the
amount of excitability chemicals and the suppression of inhibitory chemicals
such as serotonin, commonly dubbed "the happy hormone" due to its
association with mood and well being. It is because of this delicate balance of
ions and chemicals that ensuring your horse has enough magnesium is not only
vital to prevent anxiety but also to maintain proper muscle function by keeping
the muscles relaxed and preventing them from being tense, stiff or sore.
Some animals are genetically predisposed to having
sub-optimal levels of magnesium and naturally anxious people have been shown to
release greater amounts the stress hormones associated with low magnesium in
response to the same stimuli than less anxious people do. It can be assumed
that the same individual differences occur in horses. Combine this with the
fact that deficient mares will produce deficient offspring as they are unable
to provide the foal with an adequate magnesium level and it becomes very clear
as to why so often "quirky" horses pass their unwanted behavioral
traits onto their offspring. With regard to breeding, not only does the fetus
require large amounts of magnesium from the mare but the stress of gestation
and birth also deplete levels. This not only causes excessive stress to the
mare but low Mg levels in newborns are associated with low birth weights, early
complications and a decreased tolerance to stress even after infancy.
Magnesium transport must be facilitated by certain
proteins, therefore the form of magnesium ingested and the presence of other
minerals, namely calcium and potassium are hugely influential on the amount
absorbed. The presence of too much calcium is particularly relevant as the two
minerals interact and high levels effectively increase the need for magnesium.
There is not only therefore the need to supply enough magnesium in the diet but
to also ensure that there is enough Mg relative to the calcium intake. Spring
and autumn grass are notoriously "whizzing", the reason for this is
because new fast growing grass contains high levels of calcium and effectively
causes magnesium deficiency. In cattle Grass Tetany or Staggers is a common and
serious disease that results from magnesium deficiency and normally occurs when
cattle have been grazing new, fast growing pasture. Calcium is an extremely
important mineral but it should not be given in excess at the cost of magnesium
which has actually also been shown to increase bone density and strength.
Calcium absorption in the horse also occurs relatively freely and seems
unaffected by Vitamin D availability and blood plasma parameters as it is in
other species; magnesium absorption on the other hand is often limited. The
form of magnesium used is important as some absorb far better than others.
Absorption from magnesium oxide and magnesium hydroxide salts is very
poor, phosphates also hinder absorption. Magnesium aspartate hydrochloride is
ideal to provide maximum absorption and has shown positive calming results in
many species.
Magnesium dietary intake of the domesticated horse is
often not enough to meet their demand. This is in part due to the excessive
amount of stress we subject them to and also due to the lack of magnesium
availability in processed foods and acidic, sandy or water logged soil.
Although over exposure to magnesium may also be toxic, it is rare. Excesses are
excreted naturally in the urine with no detrimental effect to the action of
other nutrients; caution is only needed with animals with kidney dysfunction.
Ensuring that your horse has enough magnesium can greatly reduce
hyper-excitability, stress related behavioral problems and muscle tension and
in turn improve general well being and condition, all without any sedative
effect and the potential to actually enhance performance.
