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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, wintēr, 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, hile 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. 15618

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 (estrus 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 larve 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.

The loco tendency in the sheep may be accounted for by the presence of the tape-worm, in part, as the presence of the bot-fly larvæ may account for the depraved appetite in the horse. The explanation in both cases is of course largely theoretical, but there is certainly a sufficient basis of observed facts to make the hypothesis a reasonable one. Taking it for granted that the presence of intestinal parasites furnish a satisfactory explanation for certain animals contracting the habit, there are doubtless other causes that exert an influence. It must be borne in mind that a very large percentage of the animals in the section of the country we have under consideration procure their own subsistence directly from the wild range, and never have any prepared forage. On many ranges the pasturage becomes very short during the winter and spring, and hunger drives the half-famished creatures to eat whatever can be found of vegetable kind. This is more frequently the case since the ranges have become more completely occupied, and it is a fact that I have elsewhere referred to that the disease is now becoming known where it was unheard of a few years ago. The losses in many localities have grown to be a serious matter. I was told by different ranch men that the losses from this source absorbed all the profits there would other, wise be in the business. It is a difficult matter to give even an approximate estimate on the loss from this cause. The animals run at large on the plains, and frequently the first known evidence of the disease is the discovery of a carcass. No one can tell from what cause the animal died. Again, almost any ailment is likely to be classed as a case of loco. An animal is found to be sick, and of course shows more or less stupor and lack of activity. This is put down as a case of loco. Outside of all this, the fact is painfully apparent that a large number of animals eat the plant and that they are all out of condition; that the habit becomes fixed when once the taste is acquired, and that it uniformly leads to death if the animal is left to select his food on the range where the plant grows. It is to be presumed that the plant is possessed of some toxic property that has a specific effect on the nerve centers, and that these effects have a marked tendency to remain permanent,

I am not aware that the poison, if the plant possesses such a property, has ever been separated by analysis. I am unable to propose any very satisfactory remedy for the evil. So long as the animal runs at large where the plant grows, the evil is likely to continue. The practice of cutting down and destroying the plant has been proposed, and tried on some ranges.

The results were reported on, favorably, by some sheep men who had tried the experiment. This is, of course, a tedious and somewhat expensive method of prevention, but is not impracticable, especially for sheep ranges, where the animals are not allowed to wander over a wide range of country, I am of the opinion that this method may be profitably employed in localities where the plant does not grow in great abundance. In districts where there are considerable areas, thickly covered, these could be inclosed by a wire fence and other parts of the range could be freed from the plants by cutting. Where the area is too great or the plant too abundant for the application of either of these methods, I see no alternative but to prevent the animals from ranging over such districts. The trouble is not a serious one on cultivated or inclosed farms. The plant is rarely seen growing except on the unbroken sod. It is a comparatively easy matter to exterminate it in cultivated fields. I have not seen it growing either on plowed land or in

the alfalfa fields, or among the cultivated forage plants. Again, if the causes leading to the formation of the loco habit are such as I have above observed, animals kept on farms would be less subject to these influences than those that are free on the range. Better care, feed, and attention would materially lessen the number falling into the habit.

The disease is not an incurable one, though the administration of drugs is not likely to be followed by very satisfactory results. No drug is likely to overcome the habit, and so long as the appetite and the ability to gratify it remain, the animal will continue to grow worse. Besides, it is practically impossible to medicate the halfwild animals on the open plain. If horses are taken from the range and placed on good, nourishing diet, they will make slow recovery. Favorable results are more likely to follow this method of treatment if the animal is young and the habit not of long standing. I have seen many cases of partial or total recovery from this course of treatment. Special attention should be given to the destruction of intestinal parasites. They are especially abundant and harmful in this region of the country, and I have no doubt but thousands of supposed cases of loco poisoning are the results alone of intestinal parasites.

The winter is not the most favorable season for conducting such investigation. During much of the time I was employed the ground was covered with snow, and the work was necessarily much interfered with.

My time would not allow entering upon any system of practical experimentation. I therefore confined myself entirely to collecting the testimony of those who have had years of experience in the livestock business, and to making such personal observations as I was able to make on animals that had voluntarily contracted the habit of loco-eating

There is much need for careful experimental work in this field. A series of carefully arranged practical tests should be made, and the results fairly and faithfully recorded. It is a matter of serious import, especially to the breeders of sheep and horses on the open plains.

I trust the few observations I have been able to make may be fol. lowed by more extended and systematic effort, and that a practical solution of the trouble may be found for these enterprising stockmen of the West. Respectfully submitted.


Commissioner of Agriculture,

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