Part 63

Starvation and indigestible or innutritious food contribute to debility, and lessen the power of resistance. Hence in the poor, half starved denizens of city slums, and among neglected herds of cattle, tuberculosis, once introduced, makes rapid and extensive ravages. Conversely overfeeding often acts in the same way, developing indigestion and thereby robbing the tissues of their proper nourishment.

HEAVY MILKING.

In dairy cows, of milking breeds, the drain on the system is liable to prove too great, under a ration-for-milk, warm sloppy mashes of grains, bran, middlings, roots, distillery swill, exclusive diet of silage, saccharine roots, or marc, warm drinking water, a warm atmosphere, liberal salting, and enforced idleness in the stall, with careful stripping of the bag. The butter cows, (Jerseys, Guernseys, Alderneys, etc.) are especially liable to suffer, as the greater the yield the more the system is robbed of the adipose material which is so needful to a vigorous health. When the cow has been reduced to a high-pressure milk factory her physical size reduced to obviate the need of a large sustaining ration, and her milking capacity stimulated to the highest degree, the presence of the tubercle bacillus is especially dangerous.

CONFORMATION.

It was formerly held that cows with heads narrow between the horns, small thin necks, narrow chests defective also in depth and length, loose projecting shoulders and elbows, pendent, pot bellies, with hollow flanks, and a general laxity of the frame were especially predisposed to tubercle. In many such cases the suspected animal was already the victim of the affection, which had brought out these characteristic features of weakness and emaciation. In other cases the unthrifty appearance was due to poor feeding and care or to chronic disease, which in robbing the system of vigor and hardihood laid it open to the attack of the tubercle bacillus whenever it was introduced. Even when there was no such depressing influence affecting the individual, the inheritance of such a frame, betokened a constitution lacking in vigor, and with little power of resistance to the invading microbe. Some milking breeds which tend to the above conformation, show an unusual development of the lymph glands and plexuses, and as tuberculosis attacks the lymphatic system preëminently, the bacillus finds an especially favorable field for development in such systems. It would, however, be an error to assume that the compact, rounded frame, with circular chest and abdomen, and full, firm neck and shoulders, with a great disposition to fat and little to milk, is in any degree immune. Under the presence of the tubercle bacillus, and close stabling, they often succumb quite as rapidly as the most susceptible milking breeds. The meat producing breeds with a strong propensity to fatten, have an extraordinary development of lymph spaces and plexus in the intermuscular and subcutaneous connective tissue, and the microbe finds a welcome home in their sluggish, inactive and atonic systems as well as in the typical dairy cows.

BREEDING TOO YOUNG.

Breeding from immature animals undermines the vitality as the system is overtaxed to sustain at once the demands for further growth, for the nourishment of the unborn offspring, and for the yield of milk. Some families of Jerseys have been undoubtedly injured in this way, through the desire to diminish the size of the cow, and yet retain the highest milk and butter yield.

CLOSE BREEDING.

Inbred families are proverbially subject to tuberculosis. By pairing individuals that show in a marked degree the desired qualities of early maturity, heavy milking, or fattening, the greatest stimulus is given to the enhancement of such qualities, and with this there is the correspondingly ready receptiveness to the tubercle bacillus. To this is added a degree of constitutional delicacy which comes from too close breeding, and which otherwise shows itself in an encreasing infertility, when bred with an animal that is nearly related. In addition, the high bred animal is kept much indoors, where the bacillus, once introduced, is easily preserved and propagated, and is denied the free outdoor life and exercise which might develop muscle and vigor. This is no valid argument for introducing inferior blood to the deterioration of the economic value of a race, but rather for the complete exclusion of the bacillus which may find in our treasured herd an especially inviting field for its ravages.

AGE.

In both man and beast, age appears to have a predisposing effect, but apart from debility or trauma, this may be fully explained on the ground of often repeated infection, an indoor life, and, in dairy cows, the excessive drain upon the system. In thoroughbred herds of cattle, in which the cows are preserved as long as they will breed, and in dairies where they are kept as long as the milk yield is satisfactory, the oldest show by far the largest percentage tuberculous. In secluded individual dairies we have found 100 per cent. affected, Ostertag gives the average for Berlin at 75 per cent., and Bang for Denmark at 69 per cent.

PREDISPONENT DISEASES.

As already noted all diseases which undermine the health tend to diminish the powers of resistance to the tubercle bacillus. To be especially dreaded, are long standing diseases which produce emaciation and debility, fevers that for a length of time impair sanguification, metabolism and nutrition, diseases of the digestive organs which cut off the requisite supply of nutritive material, and, above all, diseases of the lungs and air passages that impair the tone of the tissues and invite the attack of the invading microbe. Bronchitis, laryngitis, pharyngitis and tonsilitis in all their varied forms are to be particularly noted. Even in man it is believed that one of the most common channels of infection entrance is through the open tonsillar crypts, and the same doubtless is true of animals. Pigs, with their large tonsils and frequent infection through feeding, are probable examples of this, and when, in addition to the detention of the microbe in the cavities, there is an inflammation and debility of the tissues, the opportunity for infection is greatly enhanced.

ENCREASED TRAFFIC IN (TUBERCULOUS) ANIMALS. DAIRY EXTENSION.

In common with all infectious diseases, tuberculosis owes its great extensions to the sale and purchase of animals. Where an indigenous race of cattle is raised and sold, without any additions from without, tuberculosis is usually rare and confined to the one herd, or to those having intimate intercommunication with it. Where, on the other hand, a large stock is kept up, as in milk dairies, and few or no calves are raised, but the bulk of the cows are sold off yearly and replaced by new purchases, tuberculosis, sooner or later, finds admittance through the body of an infected animal, and once implanted in the herd, it goes on encreasing, without limitation, except by the sale or death of the more seriously affected. The larger the herd and the greater the number of yearly changes, the greater the number of opportunities for the introduction of an infecting animal. Where a great part of the herd is turned off yearly, and the new animals are drawn from any or every source indiscriminately, it would border on the miraculous if such a herd were to remain free from the infection for any great length of time. The recent extension of tuberculosis in herds has been coincident with the great development of commerce in live stock, and the rapid transit on land and water by steam. Before the days of the steam engine, animal plagues advanced slowly and uncertainly, excepting in the presence of a great European war, which drew animals from all available sources, congregating them in large mutually infecting droves in commisariat parks, and marching them in the wake of the army for its daily supply. Inevitably every country invaded was infected, and the plagues spread from the line of march in all directions. The more deadly plagues, like rinderpest and lung plague, were the first to appear, and in this lay a certain measure of palliation of the evil, as the exposed and often weaker animals were killed off, so that the slower contagion like that of tuberculosis had not time to develop. This mitigating influence held good so long as the deadly plagues were not placed under effective control. When, however, a nation successfully extirpated and excluded lung plague and rinderpest, the way was opened for a freer extension of tardily developing plagues like tuberculosis. The great development of beet sugar factories and the accumulation of herds to consume the marc; the extraordinary extension of manufactures which have made England and certain countries of Western Europe consuming rather than agricultural lands, and the wonderful modern expansion of dairy husbandry have combined to encrease and concentrate the cattle industry in ratio with the manufacturing and commercial progress of the nations, and as the live stock are kept under a milk-stimulating regimen and a life passed largely indoors, the way has been open for an ever-advancing encrease of tuberculosis. In the United States the centralization of population in the Eastern States and in all great centres of industry and the concentration of cows for the milk supply, and in certain districts in connection with butter and cheese factories, have contributed to wide local extensions of consumption. Hence it has been no uncommon thing to find herds in the vicinity of cities with 20 to 100 per cent. affected, in striking contrast with the 0.02 per cent. found in the fat cattle from the plains.

The modern railway traffic brings to all these swarming centres of animal industry, live cattle from long distances to supply the constant depletion through deaths and the disposal of dry cows, and thus the whole Atlantic slope is drawn upon to fill the eastern stalls. Infected animals thus shipped from Ohio, Indiana, Illinois, Wisconsin and Michigan for the good of the herds in those states find new homes in New York, or New England, where they have four to twelve mouths to propagate the infection before they are themselves disposed of. As in the days of the lung plague in America, the eastward trend of bovine traffic, becomes to a certain extent a protection and benefit to the herds of the west, but in equal ratio it operates to the detriment of our eastern stock. What is true of the planting of new centres of infection in the busy dairy districts of the east, and of the steady increase of disease in already infected herds, through the constant addition of new cases purchased, is no less true of the corresponding districts devoted to dairying interests in the west. It is the natural order of things, that, everywhere, the new accessions of infection, coming in the lines of trade, into large dairy herds, kept to a great extent indoors for months at a time, must hasten the general infection of such herds. When, therefore, no intelligent measures are interposed to check the evil, we must expect that the marked increase in the prevalence of tuberculosis, which we have witnessed of late years, shall become more and more evident year by year. Journals have claimed credit for befriending the stockman, in opposing all control of the cattle traffic, dealers have denounced all control as ruinously oppressive and injurious, and legislators have turned a deaf ear to the warnings of science and experience, but time, in this as in all other plagues, will justify the demand for an intelligent control, and the increasing losses will one day open the eyes of the stockowners to the fact that their truest friends are those that would exclude the baneful seed, and kill it ere it has had time to germinate and bring forth its ever increasing harvests.

In the absence of any systematic and efficient government protection in this line, the stock owner can only protect his sound herd by the rigid exclusion of all animals that are not of his own breeding, or in case of purchase, by an exhaustive inquiry as to the occurrence of sickness or deaths in the herd from which he buys, and by the professional examination and test of every animal to be bought. Even then he must promptly separate, test, and, if necessary destroy any animal that proves unthrifty, or which by cough, diarrhœa, wheezing or other sign gives evidence of probable tuberculosis.

Unregulated Traffic in Tuberculous Animals from Other States. The danger of buying animals untested is in no degree lessened when they are sent in from other states. While some make a business of supplying the store market with what they believe to be good stock, there is always the temptation to turn off animals that are unthrifty or poor milkers and which have proved less profitable than the others. Some even have the herd tested and sell off those that show evidence of tuberculosis. Unless, therefore, it is held in check by the tuberculin test, the traffic is made to the extent of such sales a direct means of disseminating tuberculosis.

ASSORTING THE TUBERCULOUS ANIMALS FOR SALE IN A GIVEN STATE.

A still more injurious result comes from the order of given States, that the admission of store cattle shall be guarded by the tuberculin test of each animal, and the supineness or worse, of adjacent states in establishing no effective safe guard against the disposal of the tuberculous culls in the unprotected State. Cattle from the west or elsewhere in the United States, arrive in a great public market as, for example, New York, they are here tested, those that stand the test are shipped into one of the States requiring the test (Massachusetts, Pennsylvania, New Jersey, Canada), and those that have shown the reaction of tuberculosis are sold into the herds of the State in which they were tested. The most malicious enemy of the New York stock owners, could not devise a surer means of stocking the herds of the State with tuberculosis than this atrocious system. Yet when the present writer had a bill introduced into the legislature to correct the evil the opposing interest proved strong enough to prevent it from coming to a vote. The legislative committee on tuberculosis which sat later, and upon whose attention the subject was pressed, also practically ignored it and the statute which this commission inspired leaves the matter as bad as before. Under the present law the New York purchaser must secure his own interests by having every animal he buys tested by a trustworthy veterinarian.

Sale of Sound Animals Concentrates the Tuberculosis. The action of one or more States in admitting store cattle only after a tuberculin test, acts directly in encreasing the relative number of tuberculous animals in adjacent States. The purchaser from Pennsylvania for instance, goes into a New York herd and purchases all the best animals on the condition that they pass the tuberculin test uncondemned. It follows that the New York herd is left with the tuberculous cattle only, and those that, aside from tuberculosis, are of low value or profitless to keep. Further as the advance of tuberculosis is proportionate to the relative number of tuberculous subjects in the herd or building, and the concentration of the poison, the depreciated herd is almost certain to become rapidly and generally affected by the disease.

The Denial of Indemnity for Tuberculous Animals Killed. Several American States (and notoriously New York in the recently enacted statute) forbid compensation to the owner for any animal killed because it is affected with a contagious disease, and to prevent the extension of such contagion. All history attests, and any consideration of human nature might teach, that such a measure is only calculated to spread the infection. The owner of an animal, affected with a contagious disease, who can get little salvage by turning it into beef, and none at all if he hands it over to the State for slaughter, will naturally think of putting it on the market, where he can secure a good price. How much more is he tempted to do this when the disease is an occult one, and the animal shows the outward appearance of health, as is the case in nine-tenths of many tuberculous herds! Crime cannot be fixed on the seller, for he is not an expert, and cannot be expected to diagnose the disease. If the infected cow is of little value for the dairy, she is passed on, from hand to hand, leaving infection in every herd she has entered. The ultimate owner (in whose hands the State finds her and diagnoses her disease), though he may have bought her in good faith as a sound animal and paid a correspondingly high market price, is made to lose the whole value of the cow. The real offender who knew her to be a tuberculous animal, and sold her in consequence at the price of a sound cow is shrewd enough to keep himself out of the clutches of the law, while the honest purchaser who has been already swindled, has his income and property cut off without compensation. Such a law is self-evidently unjust; it plays into the hands of the swindler at the expense of the just man; with the object of protecting the community against infection, it refuses to call on the public for any contribution toward its own protection. The system is a direct bid for extensive and encreasing violation of the law and diffusion of the infection and must be accorded a prominent place in the list of causes. It would be surprising to find that any country ever extirpated an animal plague by working on such a system. As a matter of fact no country ever did; all such sanitary successes from the extinction of sheeppox or rinderpest in Western Europe, to the recent stamping out of lung plague in the United States, were based on a just compensation to the owners of the stock. When, therefore, veterinary sanitary principles and experience have been so far ignored as to allow the passage of a law, which at once favors the diffusion of infection by the crafty sale of the infected, the expatriation of the healthy animals from the home herds, leaving only the diseased, and finally the selection from herds in transit of the tuberculous ones to be scattered widely among the herds of the State, we must not wonder at the continuance or encrease of tuberculosis in the commonwealth. Until a more rational and common sense legislation can be secured, the unfortunate stock owner must defend himself by the expensive alternative of testing every animal he buys.

Private Testing of Herds and Sale of the Tuberculous. A most reprehensible practice is the private testing of herds and the sale as store animals of those that react. In this way a herd may be cleared of infection, but at tenfold expense to the public at large, as every animal sold may convey the infection into a separate herd. It is, however, a natural outcome of the unwise system of refusing indemnity for the infected.

Habituating to Tuberculin Testing and then Selling under Test. Many (not all) cattle, when injected with tuberculin repeatedly at short intervals, acquire a tolerance of the agent and fail to react as at the first test. We have in such cases examined the animals post mortem and found active tuberculosis. Unscrupulous owners, aware of the fact, have their diseased cattle injected repeatedly every few weeks, and as soon as they fail to respond, sell them under the guarantee of the tuberculin test. The cattle, of course, carry the infection into other herds. This swindle could be obviated if it could be made a misdemeanor to have or use tuberculin except as a State or Federal official acting for the government. This would imply the corollary that the State should test the herds when called upon.

Antipyretics During Tuberculin Test. Another method of undoing the tuberculin test is to feed large doses of antithermic agents to depress the temperature at the time the rise from tuberculin would take place. Tuberculous cattle may thus be sold as sound animals, with a certificate of having successfully passed the tuberculin test, the operator having given such certificate in perfect good faith. It suggests the importance of withholding tuberculin from public use, or of securing an absolute control of the feeding and watering of the animals during the test.

False Certificates of Tuberculin Tests. Stock owners have reported to the writer alleged tuberculin tests of their herds which were completed in three hours, and others have named instances of marking animals for shipment and giving certificates of testing where no tuberculin had been used and no examination beyond the most cursory glance had been made. This might be expected of some non-graduates, registered on a basis of alleged practice, shamefully ignorant of veterinary medicine and conscious of their false position, and some educated veterinarians thus placed at a disadvantage may have been tempted to follow suit, but it can only end in personal disgrace and an inevitable extension of tuberculosis. Begotten in a legislative wrong and nourished by moral weakness, it can only grow into greater evil. Unfortunately such unworthy actions throw discredit on the very name of sanitary police. To avoid the evil every one aspiring to the responsible work of testing cattle should be thoroughly examined as to fitness and licensed to practice under a heavy penalty for neglect or malpractice.

Feeding Hogs on Fresh Offal from Abattoirs. It has been a common practice, especially in country districts, to turn the raw offal of slaughterhouses to pigs, and as the tubercle is usually concentrated in internal organs, the hogs become infected in large numbers. In public institutions which slaughtered their own meat I have found the hogs all but universally tuberculous. The danger is only slightly lessened when the hogs are fed raw butcher and kitchen scraps in swill. It suggests the compulsory boiling of all swill or garbage containing raw meat.

Feeding Calves and Hogs on infected Milk. Though it has been repeatedly shown that the majority of moderately tuberculous cows do not yield infected milk, yet in every tuberculous herd, at irregular intervals, one or more are attacked with tuberculosis of the mammæ, and the drinkers of the milk take in the tubercle bacilli. This will happen in the most strictly supervised tuberculous herds, while in those that are less carefully managed, the milk that is considered unfit for human consumption is fed to pigs or calves. In one dairy, I found that the calves, all fed in this way afterward reacted under the tuberculin test, while the following year the crop of calves, though fed on the milk of the same diseased cows, with this difference that the milk had been first heated to 180° F., without exception grew up healthy, and not one reacted under the tuberculin test.