There is no disease which so seriously affects the feet of our horses as
“navicular disease.” Its commencement is subtle and its progress so
insidious that it is only when the malady has reached a dangerous
condition that it becomes known to the ordinary horseman. At this stage
veterinary aid is usually sought, with the result that the owner has to
be told that nothing can be done in the way of cure and very little
towards stemming its onward progress. Why, it may be asked, do we occupy
the pages of this Magazine with a subject so absolutely devoid of matter
to which attention can be profitably directed. Our reply is that if
little can be done in these directions we are not without hope of
ministering to its prevention, and for this we claim some justification
for so far imposing on our readers.
Before the days of Moorcroft and Turner navicular disease, although much
in existence, was not recognised by the profession, and the lameness
arising out of it was referred to the shoulder, with no other reason,
save that indications of disease were not detected or detectable in
other parts of the limbs. Then, as now, the feet of horses were noticed
to contract, and when this condition was found to exist the lameness was
attributed to it, and it alone. No one seems to have thought to look for
the cause of contraction, and thus to trace the _fons et origo mali_,
but all remained satisfied that the lameness arose from the pinching of
the sensitive structures of the foot by the contracting hoof.
No doubt in some measure this was true, for it is impossible to think of
a normal state of the sensitive parts of a structure like the foot being
enclosed within a small and contracted hoof. As a secondary cause,
therefore, contraction would be sure to make itself felt sooner or later
by diminishing the size of the foot and interfering with the play of the
parts within.
The peculiar stilty action which this disease induces brought into use
the term “chest founder.” This term was meant to convey the idea of pain
in the muscles of the chest, where the disease giving rise to it was
supposed to exist, and it was not until Moorcroft and Turner traced the
disease to the navicular bone that these meaningless terms ceased of
employment, and the much more rational one, “navicularthritis,” came to
be used in their stead. Whether this term is an appropriate one or not
may be open to question, but it locates the disease, and in this respect
it is distinctly useful.
_Causes._—We cannot speak of the cause of navicular disease without
referring to the influence of heredity. There can be no doubt that the
property of transferring to the offspring the weakness inherited by the
parent is just as marked in this as in any other affection, and the
writer, in a long experience, has seen numerous instances of the disease
handed down from the latter to the former. It must be understood that
the transmission of hereditary taint or predisposition is what is
understood here by hereditary disease. It is not that the disease in an
active state is born with the animal, but that the parts are in that
condition in which the disease may be easily excited in them by causes
which would not affect an animal who was not the subject of hereditary
weakness. It must not however, be stated that because a horse inherits a
predisposition to navicular or any other disease that he should
necessarily contract it. A good deal will depend upon the degree of
intensity of the inheritance on the one hand, and the severity of the
cause which acts upon it on the other. If it exists in such form as to
be easily excited into action, it is not unlikely to appear, but where
the hereditary predisposition is only possessed in a mild measure the
animal may not meet with a cause sufficiently severe by which the
predisposition can be made to assume an active state.
_Exciting Causes._—They are numerous and varied. Conformation, action,
shoeing, weight of body and general management, all play their
respective parts in causing the disease.
[Illustration: SIDE VIEW OF HEALTHY FOOT.]
[Illustration: SIDE VIEW OF DISEASED FOOT.]
[Illustration: BACK VIEW OF HEALTHY FOOT.]
[Illustration: BACK VIEW OF DISEASED FOOT.]
As to conformation, it would seem that the more upright the parts below
the fetlock joint, the less elasticity they present, and the more do
they assume a mere column of support. In this case the weight of the
body falls more directly upon the navicular bone, and the absence of
that elastic recoil afforded by the oblique pastern tends to excite
disease in it.
_Action._—This will commend itself as an exciting cause to anyone who
will watch the movement of different horses. The animal who lifts his
limbs high in the air and brings them down again almost in the place
from which he took them is much more likely to contract the disease than
the horse whose movements are less exalted and more progressive.
Especially is this the case if the body is loaded with flesh and the
horse is in soft condition.
_Shoeing._—Notwithstanding the very great benefits which have resulted
to shoeing smiths from recent efforts in their behalf by Agricultural
Societies and County Councils, there still remains much to be done ere
we can claim to have placed the shoeing of horses outside the causes of
navicular disease.
It is perfectly true that the impression left on the mind of a visitor
to agricultural shows where shoeing competitions are in evidence is
usually assuring, but it gives no idea of the general unfitness of the
great bulk of the craft to follow the chosen calling of their lives.
This is said in no want of respect for the shoeing smith, but rather
with the object of drawing attention to him as a much-neglected
individual, and one who is always thankful for anything that may be done
for him in the way of education.
Paring the sole, the frog and the bars are all still in evidence both in
town and country, but it is not always the wish of the shoeing smith
that it should be so; too often it is the wish—nay, the will—of the
owner or the coachman that the feet shall look smart, and in order to do
this the smith abandons his better knowledge to “oblige.”
Nothing tends so much to lay the foundation for navicular disease as the
repeated mutilation of these parts in shoeing. The sole, the frog and
the bars are together designed among other things to keep the heels
apart and protect the sensitive structures within, and notwithstanding
this there are still those who for reasons of their own continue to
disregard this very obvious truth and to insist on their horses’ feet
being cut out of shape and weakened to the last degree. It is never
given a thought that thickness of sole and frog is a defensive quality,
and to cut them is to weaken them and to expose the parts within to
pressure from without. Apart from bearing their share of the weight of
the body, the bars are specially intended to keep the heels open and to
maintain a healthy state of the foot, which cannot possibly exist where
they are repeatedly cut away in the act of shoeing.
[Illustration: NAVICULAR BONE.| Showing Small Ulcers invading its
Structures.]
Calks, and such means as are adopted to remove the frog from the ground,
operate unfavourably on the feet, and especially where mutilation is
part of the operation of shoeing.
Contraction of the foot not infrequently results where the hoof is
allowed to grow unduly long and the frog is removed from the ground, or
where, as the result of injury to some part of the limb, the foot is
rested for a long period. Whether the result of the one cause or the
other, it is a condition which, if not carefully rectified by shoeing,
may excite navicular disease.
It is comparatively seldom that navicular disease is found to exist in
the hind feet, and the preference which it shows for the fore ones may
possibly be found in the difference which exists in the conformation of
the limbs. The straight fore-leg allows the weight to fall directly on
to the feet, while in the hind one it is first broken and diffused in
passing through the angle forming the hock, so that by the time it
reaches the foot the sharp edge of concussion is removed and the foot
escapes the injury which is inflicted through the straighter column in
front.
_Prevalence of the Disease._—As to the horses which suffer from this
affection, it may be somewhat difficult to say in which particular
variety it is most prevalent. Between the light and heavy horses there
is a great difference in favour of the latter, although since they have
been called upon to do so much trotting work the malady has increased in
the same proportion. There is a much greater number of cases among
harness horses than any other description, but it must not be forgotten
that they are the more numerous. And on this account we should look for
more cases than are to be found in the other varieties.
Hunters are frequently found to be affected by navicular disease,
although their work is for the most part over soft, yielding ground.
These animals suffer most when made to jump from high banks into roads,
especially when the muscles are tired and have lost much of their power.
In these circumstances the full weight of the body falls upon the feet,
with the result that the navicular bone may suffer by impact with the
ground and become the seat of disease. But apart from these special
accidents, hunters become subjects of the malady as the result of
constant wear.
The racehorse, as such, is comparatively seldom the victim of this
affection. So long as he is in training he is constantly on the turf,
and at an early period is relegated to the stud, and ceases to be
exposed to the causes by which the disease is excited. If, however, he
does not himself contract the malady, his peculiar habits of life have a
tendency to weaken the feet and to predispose his stock to contract the
disease. In this way he becomes a factor in its propagation. His
constant absence from the hard road does little to encourage the
secretion of a thick, strong horn, and to impart to the feet that flinty
hardness so much to be admired in a sire. “No foot, no horse,” is an
axiom as true to-day as it was when first formulated by Lafosse. This is
not said to prejudice the thoroughbred, for which the writer has a very
high regard as a sire both of hunters and harness horses, but rather to
hold out the caution to those who use him.
_Symptoms._—There are few diseases in which the symptoms are so obscure
and ill-defined in the earlier stages as they are in navicular disease.
The situation of the injured part forbids that inspection and
manipulation which we may readily apply to other diseases, and there is
too frequently no visible effects of the injury to guide the expert, but
only an insidious and slowly progressive lameness.
It is more than probable that for some time the owner will be in doubt
as to whether there is any defect at all. The only change observable to
him is an uneasy sensation experienced when the horse is ridden in his
fast paces. Soon, however, the defect becomes obvious in one leg or the
other, and later in both.
At this time careful search may or may not discover visible contraction
of the diseased foot. This condition, however, soon follows on by
resting the foot in the stable or relieving it when at work. In the
former case it is partially flexed and advanced more or less so as to
take it away from the bearing, and in the latter the heel is kept as far
as possible from the ground, and the weight is thrown on to the front
part of the foot. All the changes which follow upon this are in the
direction of contraction of the heels, and as this takes place the foot
narrows behind. With the progress of the disease and the constant use of
the sound foot it also begins to show signs of trouble, and the lameness
which had hitherto been confined to the one now appears in the other.
Knee action becomes defective, the step is short and “proppy,” or, as it
is commonly expressed, “groggy.” On leaving the stable the horse is very
lame, but as he continues to move the lameness in great measure passes
away. The fore limbs are now upright, or he stands over at the knees, a
fulness appears in the hollow of the heel, the foot becomes blocky, and
the crust thick and dense, the sole is unusually concave, the frog
wasted, and may be affected with thrush.
_Treatment._—It may be accepted as true that once the disease is started
its progress continues, and sooner or later brings its victim to the
knacker’s.
In some horses the malady makes slow progress, but in others it is rapid
and destructive. If the disease cannot be cured by the adoption of
palliative treatment, much useful work may be obtained from an animal
affected by it. When navicular disease is known to exist, special
attention will, of course, be given to the shoeing. Here much may be
done to keep the disease in check.
We see by the concavity of the sole and the contraction of the heels
that the latter have not been allowed to come to the ground in the
ordinary way. This is the keynote to which attention must be directed in
regard to treatment. The heels must be defended by slightly thickening
the shoe at this point, and the introduction of a leather or
india-rubber band to break the jar on concussion.
The crust must not be allowed to grow unduly, but must be kept down by
occasional rasping. By doing this, contraction of the foot is to some
extent prevented, and the conditions of its elasticity preserved.
When in the stable a cold wet swab should be worn; it softens the hoof,
prevents contraction, and enables the animal to work with comparative
ease. Horses with navicular disease, especially those advanced in years,
should be kept at work. Of all occupations none suit these animals like
working on the land, where the feet meet with the least resistance. Mild
counter-irritants to the coronets while still working may be applied,
but on no account should the animal be allowed a “long rest,” during
which he loses condition, and with it all the courage by which he has
been enabled to “suffer and to work.”
The last and final act in the treatment of navicular disease is division
of the plantar nerves.
[Illustration:
THE BEECH.
]
The effect of this operation is not to cure the disease, but by severing
all connection with the brain, to prolong his working powers. This done,
the animal ceases to feel the pain which troubled him before, and
commences to use the diseased foot without giving it the slightest
protection. The lameness, which was evidence of the care he bestowed
upon it, passes away, and the foot, weakened by disease, resumes the
work it did when in a sound condition. This tends to aggravate the
mischief, and sooner or later to bring him to the hands of the knacker.
The Beech as a Commercial Tree.
There can be no doubt that the oak takes precedence of all our forest
trees, both on account of its place in English hearts, and its visible
expression of strength and durability. The lover of Nature, too, sees in
it the emblem of all that is grand and beautiful, its mighty trunk,
great spread of branches, and dignity of age. Nevertheless, the beech
takes a firm hold of our sympathies, and, as an ancient writer has
observed, it may be looked upon as the Venus among trees. There are in
the tree a few characteristics which belong to no other, and which lend
a charm all its own; the lovely canopy of green, the high columnar
trunk, standing grey among the greenery, and the great open space
beneath, broken only by the lovely green of the holly bushes which
almost invariably attend it. The view through the forest glade is
unobstructed by coppice growth, for no bushes but the holly will grow
beneath its spread of branch.
What can be more beautiful than the open glade, carpeted with the brown
leaves of the late autumn, the dark glossy holly leaves and the tall
grey columns?
Commercially, too, when in quantity and well grown, it is universally
valuable; and the quantity which an acre, well stocked, will produce is
very great.
The tree, though the fact is questioned by many old writers, is
doubtless indigenous, though not confined to these small islands; for it
is found throughout Middle and Southern Europe, Western Asia, and
elsewhere.
The beech belongs to the natural order _Amentaceæ_, or _Cupuliferæ_, as
some prefer to call it, and to the genus _Fagus_. It is monœcious,
leaves simple and deciduous, and its fruit is known as mast. From the
mast, or nut, may be extracted a valuable oil, used for culinary
purposes, and also a flour or meal, used in some countries as food for
man. In this country it is used only as pig food, and it is from this
that the term “masting” is derived.
The leaves, enormous in quantity, decay rapidly, and soon become
incorporated in the soil, thus providing the food which the tree
requires. Beneath this natural carpet the seeds lie, and with the
admission of light and air, soon grow and develop. There is no British
tree which lends itself so completely to natural reproduction; neither
can any artificially planted beech compare with these natural offspring
for rapid growth and quality of timber.
It is not necessary to point out to the owners of beech estates the
importance of managing the natural thicket from infancy to maturity,
because such is known already and recognised; and if an example of sound
British forestry be wanted, it is to these areas we should turn.
Nevertheless, there are many estates with few or no beeches growing upon
them which are naturally suitable to their full development.
Under these conditions it is necessary to resort to artificial stocking,
and here lies the difficulty, for the beech is by no means a tree which
lends itself to rapid establishment. Whether such is best performed by
the sowing of seed, planting of seedlings, or of nursery trees of more
advanced age, is a question for foresters. Again, is it well to plant
pure and close together, or to plant with Scots pine, larch, or other
trees? Opinions vary, and no decisive advice seems requisite.
As a natural seedling the beech will find its way through almost any
tangle and force its way to the light, hindered only by the thick canopy
of the parent, but as a transplant its vigour is defective.
The beech may be divided into two classes—the beautiful wide-spreading
tree of the park, with its branches sweeping the sward; and the tall,
straight column, topped with a canopy of lovely green—branchless for,
perhaps, fifty feet and more.
It is to the latter that the merchant looks for his supply of timber,
and to which the owner looks for his revenue. The former, through its
charm, lends to the estate a value by no means inconsiderable; but the
latter, under favourable conditions, yields so regular a return that it
may be reduced to a yearly revenue. Under proper management there should
be a continual cutting and a continuous and progressive growth: there
should be no periods of vacancy.
If some of the schemes for the planting of waste lands—many of them wild
and impractical—should reach ripeness, it is to be hoped the beech will
be planted on soils suitable to its development—and these are calcareous
loams resting on a rocky bottom—because there is likely to be a demand
at a fair price, this class of timber not being much affected by foreign
imports.
Beech reaches a useful and commercial value in from forty to sixty years
when growing naturally close together, and under proper and judicious
thinning; but if such be left until decay sets in, the value per cubic
foot is greatly diminished. Trees will, of course, live and grow for a
much longer period; but after, say, eighty years, it is doubtful economy
to let them stand.
Another feature in the beech is that when decay once sets in it is rapid
in its progress, and the tree dies as a whole. The oak will live for
centuries in a decayed and dying condition, but not so the beech; and it
is only when the timber is sound that the best price can be obtained. It
is, too, a timber which soon stains if exposed, so that conversion
should follow cutting.
What is necessary for the successful growing of beech may be summed up
in a few words: A suitable soil, close contact, felling when
commercially ripe, and speedy conversion.