Part 102

Care should be taken to change the water as well as the food.

Finally every drain upon the system should be lessened or stopped. The milk may be dried up and the animal should not be bred. Sweet, dry buildings, pure air, sunshine and grooming are important auxiliaries.

In severe outbreaks, in high conditioned animals, the owner often consults his interest, in sending the victims to the butcher as soon as the affection shows itself and before time has been allowed for the inevitable emaciation and loss.

Some, on osteo-malacia lands, have profited by changing the entire herd every two years, as they become rapidly worn out under successive attacks.

As local derivatives, oil of turpentine, hot vinegar, tincture of iodine and biniodide of mercury have been employed. Open sores are treated with antiseptic lotions, creolin, lysol, carbolic acid, iodine lotions, iodoform, etc.

RAREFYING OSTEITIS. OSTEOPOROSIS. OSTEO-MALACIA OF THE HORSE. BIG HEAD.

Definition. Distinction from rachitis. Process of rarefaction, cell proliferation, congestion, solution of earthy salts and fibrous matrix, osteoclasts, Howship’s lacunæ. Dried bone light, spongy, friable, though enlarged in repaired cases, dense, heavy. Face lesions. Dyspnœa. Dropping teeth. Causes: microbian hypothesis, disturbance of bone nutrition, faulty food, lack of bone salts, cellar stables, floor on ground, malaria, cold, damp soils, city life, early life, breed, asses and mules, breeding. Nature. Symptoms: illness, inappetence, lifelessness, early fatigue and perspiration, stiffness, lameness, distortions, stumbling, knuckling, arthritis, tender puffed joints, thickened softened bones, facial swellings, narrowing of intermaxillary space, chisel teeth, difficult mastication, shedding teeth, emaciation, marasmus. Phosphates in urine when disease is active. Relation to exostosis. Prevention and treatment. Hygienic, move from cellar stable, or ground floor, secure air space under floor, ventilation, warmth, sunshine, grain feeding, pasture, change food, rest, salicylates, salicin, salol, phenacetin, blisters, phosphates, bone dust, phosphorus, bitters, iron, barium chloride.

Definition. A form of osteo-malacia occurring in the mature as well as in the growing horse, characterized by the absorption of earthy salts from the walls of the cancelli and Haversian canals with excessive production of the organic basis and cell elements and enlargement, softening, lightness and fragility of the bones.

It differs from rachitis essentially in this that while the latter attacks the young growing bone at the chief seats of growth, under the periosteum and in the epiphyseal ligament, and therefore especially on the surface of the true bony tissue, osteoporosis attacks the formed and often the mature bone in its interior, producing attenuation of the walls of its vascular canals and cancellar cavities and increase of their fibro-cellular contents. Both result in enlargement of the bone, but in rachitis this is determined largely by deposition on the surface while in osteoporosis it takes place by expansion from within. The further distinction that rachitis appears enzootically and osteoporosis sporadically applies only to localities in which the latter is not common. At different points on Long Island, in New Jersey and on the rich soils in the Mississippi valley and on the Atlantic and Gulf coasts, osteoporosis often prevails enzootically and has its recrudescences like rachitis.

The process of rarefaction and softening may be thus stated. In the Haversian canals and narrow spaces there is an active proliferation of cells and increase of vascularity, with a gradual solution and removal, not only of the earthy salts, but also of the fibrous matrix in the walls of these spaces. As in the normal changes in bone, the absorption appears to be effected through the large cells or osteoclasts grouped around the blood vessels. In the osseous tissue, which abuts on the vascular tissue, are to be found excavations, simple or irregular, (Howship’s lacunæ), containing granular cells and the larger osteoclasts. In a similar manner bone is softened and absorbed in connection with tubercle, or the pressure of tumors, aneurisms, actinomycosis. In case of recovery, repair takes place by the disposition of new bone, so that the enlarged and rarefied bone may in the end become harder than before. This applies especially to the cancellated bone. On the articular ends of the affected bones, the granulation tissue makes its way into and through the cartilage of incrustation with resulting active disease of the joint.

The condition of the bone is well illustrated in the dried or macerated specimen. Taken from a bad case in the active stage of the disease, it crumbles under pressure and weighs as light as a sponge, whilst from an advanced or recovered case, it is hard and resistant, and weighs as much more than the normal bone as it exceeds it in bulk. The morbid rarefaction usually affects the whole skeleton more or less, yet in perhaps the majority of cases; the change is greatest in the bones of the face, and the resulting distortions are usually symmetrical on the two sides. It may show mainly in the maxilla, which is thickened to twice or even five times its normal thickness, it may show in rounded, general swelling of the nasal and superior maxillary bones and those around the orbit, or it may involve the turbinated bones, the vomer and even the cartilaginous nasal septum. Loosening and evulsion of the molar teeth is common and snuffling breathing may occur as in rachitis affecting the nasal bones of dogs and swine.

Causes. We are still in the dark as to the essential cause of rarefaction of bone. There is a growing tendency to suspect a microbian origin, and many facts are held to point in that direction. It seems to have been unknown in England in the early part of the 19th century, and is not noticed by Blaine, Youatt, Percivall nor other of the early writers. In Varnell’s cases the same man had two farms not far apart and equal in soil, drainage and stabling, stocked with horses bred from the same parents with the same kind and amount of feed and work, yet on one farm six cases of osteoporosis occurred, and on the other not a single case. McNeil, in charge of street car stables, found the disease destructively prevalent in the best appointed stables and absent from others in the worst hygienic condition. In a superior stable with 220 horses he had 47 cases in two years, and in a fine stable with 100 horses he had 26 cases in the same length of time. In the poorer stables, the horses bred in the same way on all kinds of soils and with no difference in feeding nor management escaped. It is the common experience in Europe and America that a farm or district, which has been previously free from the disease suddenly has an outbreak in enzootic form, and this will last for a year or two, then remit only to appear with its old force after an interval of some years. Even during the active prevalence of the disease on one or on several adjacent farms, others in the immediate vicinity, and differing in no appreciable way, geologically, hydrostatically, in buildings, food, water, general management nor work, completely escape. Berus, Hoskins and other city veterinarians have noticed, that it was almost the rule, that a fresh horse put in the stall of one that had suffered from osteoporosis soon contracted the disease.

W. L. Williams noticed on two different farms in Central Illinois, on which the disease suddenly appeared, that for years after the comparative subsidence of the affection there was an unusual prevalence of spavins, splints, ringbones and other diseases of the bones. Meyer has noticed that cases sent from Cincinnati into the country, and that have got well, will succumb to the affection if brought back into the city stables in which they originally contracted it.

All of this points very strongly to one of two things; either a pathogenic germ in the system of the affected animal; or the presence of a pathogenic microbe in the stable, water, or other part of the environment, the toxic products of which are taken into the animal system.

But as yet no specific pathogenic microbe has been demonstrated so that this doctrine must still be held as a mere plausible hypothesis.

Many veterinarians with long experience in such cases absolutely deny contagion. The hypothetical contagion undoubtedly extends slowly, and uncertainly from animal to animal, probably, like actinomycosis, taking place mainly through the soil, or some outside medium, rather than by direct contact; or a special susceptibility on the part of the individual animal may be necessary to render it effectual.

Accessory Causes can be spoken of more confidently but even of these no one, nor small group, can be advanced as essential. The process of bone nutrition is readily disturbed by a variety of conditions, and such disturbances may easily become the occasion of weakening the resisting power and mayhap of admitting the hypothetical microbe to get in its pathogenic work.

Faulty food has been a favorite explanation. A lack of lime in the soil and fodder seems, at times, to have had a baneful effect, if only, in lowering the general tone and impairing the nutrition. Yet we see osteoporosis on limestone soils (New York, etc.), and in animals generously fed on grain. The same remarks apply to phosphorus and phosphates. Their deficiency apparently contributes to the production of the disease, and yet under other conditions, their abundance is no barrier to its development. The excess of free phosphorus produces osteitis and it is held by some that an over-abundance of phosphates acts in the same way. It has been sought to incriminate a too nitrogenous diet in some cases, and in others one too rich in fat or carbohydrates. The many cases in Philadelphia and Pennsylvania were mostly in animals that had been well fed and were in good condition when attacked (Marshall).

Special food may be the direct cause, bran diet has been already noted. Hinebauch found an acute osteitis with bone softening and arthritis in horses fed on millet, green, partially matured and ripe. Horses elsewhere have fed on millet, without such results, but not perhaps, in the same environment, nor in presence of the hypothetical microbe. Millet is not the sole nor common cause of osteoporosis, but there is reason to suspect that it is at times an important accessory cause.

Of all prejudicial conditions none is to be so dreaded as unwholesome stables. Of 200 cases reported by Berus, in Brooklyn, almost all were in cellar stables or those with floors laid on the soil. Meyer finds that “most all cases can be traced to an unwholesome atmosphere, or gases arising from vaults, sewers, cellars, filthy streams, or from a hollow space under the floor.” Harbaugh says every case was stabled in damp, ill-drained, unventilated and badly lighted buildings. The worst outbreak was in a basement with a damp wall, on one side, and none suffered except those that stood next to this wall. The horses standing on the opposite side, which was on a level with the ground outside, escaped. Removal from a cellar stable to the floor above, put a sudden stop to the appearance of new cases. James, of St. Louis, found 20 successive cases in a stable on a dirt floor, and Jasme, of Charlestown, finds nearly all his many cases on earth floors in malarial regions.

Malaria has been blamed, especially by southern observers, accustomed to see the disease on the warm alluvial seaboard and river bottoms. That this environment predisposes to the disease, by undermining the health, is doubtless the case, but in spite of occasional remissions in the symptoms, malarial germs cannot be set down as the constant cause. One of the worst cases I ever saw, with every bone in the body soft, spongy and light, developed at Inglis Green laundry, Edinburgh, where malaria is absolutely unknown, but where the brook received large quantities of chlorine.

Cold is an undoubted factor, though the disease is most prevalent in our warm southern states. Many veterinarians have noticed its coincidence with rheumatism, in which cold is so often the dominating accessory cause. Some have even suspected that it is only a modified type of the rheumatic condition. Hinebauch found his cases of millet disease in cold basement barns, or with leaking roofs, so that the floor and bedding were constantly wet. He found that cold always aggravated the disease, and bad air even more so, while salicylates seemed to have a marked curative influence.

Damp soils should be named in this connection. These not only chill the air by evaporation, and condense the cold dews at night, contributing to produce the extremes of hot noon day and cold night temperature, with corresponding disturbances of the bodily health, but they favor the preservation of the infinitesimal forms of life (bacteria, protozoa) and therefore of the hypothetical microbe of the disease.

City life is a most potent cause. Berus tells us that hundreds of horses die yearly in Brooklyn of osteoporosis, and that if sent early to the country a large proportion recover. The same is true of New York City and Philadelphia. Of Cincinnati, Meyer says that he has failed to find a case more than five miles outside the city limits, and that cases sent to the country make a partial or complete recovery. If returned to their former city stables, nearly all contract the disease anew within a year.

Many cases, however, are found in the country and often within a circumscribed area. These indicate, as in the city cases, a localized cause, bacteridian or otherwise.

Early life predisposes, the majority of cases taking place before the sixth or seventh year, yet the disease occurs at all ages up to twenty years and over.

Breed does not seem to make a material difference, and though Shetland ponies have acquired a bad reputation, their propensity to become fat and soft, their too often idle, pampered life, and the confined quarters in which they are frequently kept, account for much of the mortality.

Asses and mules habitually escape, even in the South, where the latter animal is so numerous and often so poorly kept. In Hinbauch’s millet disease, the mules suffered more than the horses.