Изображения страниц
PDF
EPUB

to find pleuro-pneumonia, for I knew your inspector, Dr. Wray, had, within the last few weeks, destroyed three herds, one belonging to Mr. Elon Behrend, at Seat Pleasant, one to Mr. D. M. Nesbit, College Station, and one to Mr. S. B. Holton, Hyattsville. As these stables were several miles apart, I felt it my duty to examine very carefully all the cattle in this section of the county. To do this has taken much time. Most of the cattle here are purchased at the stockyards or from dealers in Washington. Careful inquiry convinces me that pleuro-pneumonia has had a home in the District of Columbia and vicinity for many years, and very likely was brought here from the North during the war.

I could hear of many farms and dairies where this disease is said to have prevailed, more or less, for several years. Many dairymen have learned to diagnose the malady, and when it appears the sick cattle are disposed of at once. Owing to this practice, very few cases are to be found.

I have been able to locate the disease in but one herd, that of Mr. John W. Gregory, near Seat Pleasant, a short distance from the District line. His herd contained over 40 cows and young stock. Here I found several chronic cases, and much coughing all through the stable. Mr. Gregory told me that two or more years ago he lost several cows with pleuro-pneumonia, and had some animals now in his stable that had recovered (?) from the disease. These cows it was not difficult to find, and in my opinion were such as were liablo to spread the disease, and I reported them to Dr. Wray, who, I understand, is about to destroy the whole herd. Every animal on farms near this place has been inspected, and many of them by Dr. Trumbower, but we have been unable to find any others diseased. I have also examined all animals near College Station and Hyattsville, and find no signs of pleuro-pneumonia.

They are liable to get disease here from the District of Columbia, where I have good reason to believe the plague has a foothold. Í should be glad if the District could be inspected at the same time as the counties bordering thereon.

Much interest is felt in the county because of a few cases of glanders among horses lately discovered here. Some time in May or June Dr. Ward, State veterinary officer, condemned and killed 4 head belonging to Mr. Smith, near Hall's Station. On June 15 I found two more cases on the farm of Mr. A. O. Brady, near Forestville. I at once notified Dr. Ward, but before he arrived one of the horses died ; the other was appraised and killed under State law. Others on the farm were placed in quarantine.

Swine plague has for many years prevailed here, until the farmers have ceased to raise hogs to any extent. Farmers all over the county are deterred from attempting to raise them for fear of the disease. I found fewer hogs here than any county visited in the State. Instead of estimating three logs to a voter here, I am sure there can not be found over one hog to a voter now. This would give 6,807 as the number of hogs in the county, and at $5 per head we have a total value of $34,035. The very lowest estimates made as to the losses last year are from 50 to 75 per cent. Taking 50 per cent., the very lowest, and we have $17,017.50 as the total loss for 1886. I believe this to be below the actual loss. Respectfully submitted,

F. W. PATTERSON, M. D.. Inspector, Bureau of Animal Industry.

THE “LOCO” PLANT AND ITS EFFECT ON ANIMALS.

SIR: I have the honor to submit the following report of the results of an investigation directed by you:

The work assigned me was the investigation of the disease known as Loco.This is a term which has attached itself to a certain disorder familiar to many Western ranch men. The term is by no means an inappropriate one. It is the Spanish expression for“ foolish” or “cranky." While the term is used simply to designate a certain affection, it is intended, also, to convey a notion of one of the characteristic clinical symptoms of the disease. The same term is applied also to designate one or more species of plants, which are generally supposed to have some connection with the disorder. These are the Oxytropis lambertii and Astragalus mollississimus.

The term (“Loco"), then, is applied to both the disease and the plant supposed to produce it. · The disorder is known throughout a very large section of the western and southwestern portion of the United States. It is known in the western portion of Kansas and Nebraska, and extends to Texas and Mexico, westward to California, and north to Wyoming, and probably to Montana.

The territory I visited during my investigations extends from the western boundary of Nebraska to Salt Lake, and from Cheyenne to El Paso. In addition to personal observation, I endeavored to gather from the most trustworthy sources what verbal testimony I could that would tend to throw light on this subject. With this end in view I visited the headquarters and camps of many of the most experienced ranch men in Colorado, New Mexico, and Texas. So far as I was able I attended the local and general meeting of stockmen, and by this sort of personal contact with the practical men of the plains I was able to summarize the experience and judgment of these men. I spent much of my time on the range and ranches, observing the peculiarities of the afflicted animals, and making frequent post-mortem examinations of animals that had recently died from the disease, or those that had been destroyed for that purpose.

As to the testimony of stock-owners, it is pretty uniform, as given by those who have had personal experience with the trouble. I found a number of ranch men, and especially those who have their land under ditch” and cultivate their crops and care for their stock according to usage on farms further east, who had but recently heard the term “loco" for the first time, or anything concerning its significance. Others had witnessed, years ago, the same effect as we now attribute to eating the loco, but for which they had no explanation at the time. In other instances there was abundant testimony that the appearance of “loco" with any serious results was of recent date. This was notably the case on the foot-hill ranches back of Longmont and Greely, Colo.

Some of the most intelligent and observing horsemen, who had been in the business for a quarter of a century, had recently come to a knowledge of the existence of the malady. It would seem, from the evidence furnished by such men, that the cause, whatever it may be, had not been operative in their localities till a recent date.

It is the testimony of those who have known the loco plant for a number of years that it does not grow with equal luxuriance during successive years, and that in time it will almost entirely disappear from localities where it has been recently abundant.

On the other hand, its presence in many localities has but recently come to the notice of observing men.

The plant grows from a pointed tap-root that extends some feet into the earth. During the fall, winter, and spring months, a thick tuft of compound leaves radiate at the surface of the ground and frequently cover a circular space 8 inches or a foot in diameter. These leaves present a pubescent or downy appearance, and remain comparatively fresh and green during the winter. During the summer the plant sends up a number of slender seed-stocks to the height of a foot or more, and on the top of each is a small seed-pod, containing a number of minute black or dark brown seeds. One plant is capable of producing several thousand seeds. Such is the plant, and during the summer, when in full foliage, the ground may be entirely covered over for a considerable extent.

Its habit of growth, as I observed in most places in Colorado, was in detached bunches. Sometimes a number of tufts could be seen on a single square yard of land ; in other instances it was necessary to search carefully over an acre or two to find a single tuft, while much of the country is entirely free from the plant. It seems to be most abundant in southern and southwestern Colorado, in some sections of New Mexico, in western Texas, and I am informed it grows in great abundance in Chihuahua and other portions of Mexico. During the winter and early spring months, when other vegetation is dead and dry, the loco plant presents a tempting appearance, quite in contrast to the short dry pasturage of the plains. Notwithstanding this fact, it is uniformly rejected as an article of food by all classes of animals under ordinary conditions. Animals that have not acquired an artificial taste for the plant can not be induced to touch it. Occasionally one meets with an animal that is possessed of the keenest relish for the plant. He persistently rejects all other forage, and if the loco is not abundant, he spends his time in the most diligent search over the range for the now favorite plant. I have seen a single animal miles away from any other individual of the herd, carefully searching as if for some lost object, and when a loco plant is found he would devour every morsel of it with the greatest relish. As soon as one plant was eaten he would immediately go in search of more, apparently oblivious to everything but the intoxication afforded by his one favorite article of food.

Animals possessed of the appetite do not always behave in this manner. If the herd is grazing on a range where the loco grows, the victims of the habit remain with the herd and move from place to place with them.

The habit of loco-eating once formed it possesses for the victim all the suicidal fascination of the “opium habit.” The intemperate fascination becomes stronger, and voluntary reform, I believe, is absolutely unknown.

When animals that have not been too long addicted to the habit are confined and kept on food free from the plant in the course of time they will lose their appetite for it and reject it when offered. I have seen animals thus forget the habit in the course of two or three months. Old animals that have been loco-eaters for a considerable length of time do not readily lose the habit.

Animals that have this habit are said to be “locoed." No animal having the loco habit is in a normal physical condition.

All individuals do not show the same morbid symptoms; but all show similar structural changes, varying in degree and accompanied by a change from the normal physiological function.

All confirmed loco-eaters become physical wrecks. The symptoms do not develop rapidly, but a general derangement of the nervous system follows, which is usually accompanied with more or less disturbance of the digestive apparatus. There is general loss of nervous power; the animal becomes dull, spiritless, and inattentive. He wanders about in an aimless, half-dazed condition, except when searching for his favorite food.

Groups of afflicted animals will sometimes congregate together, when they present a peculiar spectacle of stupor and dementia.

In time loss of flesh and general prostration is followed by death. Some months are usually required for the disease to run on to a fatal issue.

I have seen animals that have shown some of these symptoms for years. This is true in those cases where the animal has suffered severely, and afterwards been placed in such circumstances that he could not gain access to the plant. Important tissue changes had already taken place, leading to alteration of nervous function, from which the animal would never recover.

The same thing is true of animals that are kept in inclosures, where the plant grows in limited quantities, and the animal is never able to get enough at any one time to bring on the more severe symptoms.

Animals that are affected with this passive type of the disease will present no abnormal appearance when running at large, or standing quietly in the stable or corral. It is only when put to vigorous exercise that the more violent symptoms are discovered. It not infrequently occurs that one of these passive-looking creatures, when put under the saddle, or even when a rope is thrown over him, suddenly begins to act as though he were possessed. Under the stimulus of this sort of excitement he is suddenly transformed into the most wild and frantic creature of which it is possible to conceive. This is not due to the unbroken condition of the animal, for old and wellbroken saddle horses will behave in this manner. This intense nervous excitement may be witnessed in the more marked cases. When suddenly disturbed, an animal may be so affected as to present the most perfect spectacle of stupor and inactivity, yet where a rope is thrown down before him he will jump over it as though he were clearing a fence.

It is a generally accepted belief among ranch men that when a horse is once under the influence he never recovers from the effects of the plant, no matter whether he continues to have access to it or not. I do not think this is literally true, though there are cases that might lead to this sort of generalization. Here are three observed facts: First, none of the herbivora ordinarily eat the loco plant; second, when once the taste is acquired the animal takes to the plant

S. Mis. 156-18

with the greatest voracity; third, all loco-eaters are diseased-are locoed—and manifest a general uniformity as to symptoms.

These facts I made personal observation of in numerous instances, and this is in accordance with the almost uniform testimony of men who have had years of practical experience with the live-stock business on the plains. It may be said, however, there are those who hold there is no such disease as “loco," save when it exists in the brain of those who believe in its existence.

I endeavored, so far as possible with the time and means at my disposal, to ascertain what pathological conditions there were that might serve as an explanation of these phenomena. With this end in view I made a large number of post-mortem examinations with pretty uniform results. In every instance there was serious effusion in the lateral ventricles and well-marked hemorrhagic clots in the fourth ventricle. The arachnoid space in some instances was likewise filled with serous effusion. The liver was dense in structure, there evidently being an increase in the fibrous tissue. The contents of the stomach and intestines were semi-liquid in character, and not over abundant. In many of the subjects there was evident lack of nutrition. There was one very noticeable condition present in every case, viz., the presence of the larvæ of the bot-fly (æstrus equi) in most extraordinary numbers. There was not a single instance in which post-mortem examination failed to reveal immense numbers of the larvæ adhering to the walls of the duodenum. This condition I found to be uniformly present, whether the animal had died from disease or had been destroyed for the purpose of examination. The duodenum was in every instance so thoroughly choked by the presence of larvæ that serious interference with digestion might reasonably be expected. The question would naturally arise as to what connection this phenomena had with the disease, if any. Certainly the presence of the parasites would not account for the clinical symptoms, especially in those cases that were more or less clearly marked for years, as the larvæ would be dislodged and disappear from the alimentary canal at the expiration of a few months. I do not regard it as improbable, however, that the presence of the parasites have to do with the development of the abnormal appetite that leads the animal to crave what he would not otherwise touch. One of the well-recognized effects of intestinal parasites is a vitiated appetite. It is not usually considered that the presence of the larvæ of the bot-fly in limited numbers produces any appreciable disturbance. But in the cases referred to they were present in unusual numbers, and had affected a lodgment not in the stomach, their usual habitat, but in the duodenum. I am inclined to the belief that the conditions were such as might account for the appetite, but certainly nothing more than this.

In a few instances cattle have been found eating this “loco plant," and are affected in the same manner as horses. Sheep quite frequently become loco-eaters, grow stupid, emaciated, and eventually die.

I made a number of post-mortem examinations on sheep and found all locoed animals to be badly affected with tape-worm. I took 22 tapeworms from the intestinal tract of one sheep, selected from a bunch of loco patients. Sheep are affected much in the same manner as horses. When in a state of repose they are very dull and stupid, but manifest excitement when disturbed.

« ПредыдущаяПродолжить »