Part 3

Feeding experiments with barium salts on animals in the laboratory 57

Barium poisoning in man 62

Pathological lesions in experimental barium poisoning 65

Toxicity of various aqueous extracts of loco plants 66

Theoretical antidote for loco-weed poisoning 71

Action of barium on domestic and farm animals 72

Application of the results of these investigations to the range 74

Conclusions 75

Index 77

BARIUM, A CAUSE OF THE LOCO-WEED DISEASE.

=GEOGRAPHICAL DISTRIBUTION OF THE LOCO-WEED DISEASE AND ALLIED CONDITIONS.=

In our Western States there is a marked annual loss of stock due to various causes. Some of these animals die in a condition known as "locoed," a term derived from the Spanish word "loco," meaning foolish or crazy.

This disorder extends from Montana to Texas and Mexico, and from Kansas and Nebraska to California.

In 1898 the United States Department of Agriculture sent out, under the immediate direction of Mr. V. K. Chesnut, a request for information concerning the ravages of the loco disease. It was found that in the ten States of California, Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, Texas, and Wyoming the loss in 1898 was $144,850. Of this amount, $117,300 was attributed to Colorado alone; in fact, the disorder spread so that this State expended more than $200,000 in two years and over $425,000 in a period of nine years in attempts to eradicate the loco plants, the supposed cause of the trouble.

The loss in one area of 35 by 120 miles in southwestern Kansas amounted to 25,000 cattle in 1883. This loss in stock has been so great that the raising of horses has of necessity been abandoned in certain areas on account of the prevalence of these loco weeds.

It is difficult to obtain accurate data, as the ranchmen believe that any information as to the prevalence of the disorder would interfere with the value of their stock.

Dr. James Fletcher, of the Central Experimental Farm, Ottawa, Canada, testified before the Select Standing Committee on Agriculture and Colonization that he had never seen a case in the North-west of a Canadian bred animal being locoed, although the loco plants were prevalent. He explained this absence of loco disease by the abundance of grass on the range, because of which the animals do not acquire the habit of eating loco plants. Cases have been reported, however, in Manitoba.

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FOOTNOTES:

Stalker, M. The "Loco" Plant and Its Effect on Animals. Bur. Animal Industry, 3d Ann. Rept. (1886), p. 271. 1887.

Bur. Animal Industry, 6th and 7th Ann. Repts. (1889 and 1890), p. 272. 1891.

Day, M. G. Loco-Weed. In F. P. Foster's Reference-Book of Practical Therapeutics, vol. 1, p. 587. 1896.

O'Brine, D. Progress Bulletin on the Loco and Larkspur. Colo. State Agric. Coll. Bul. 25, p. 18. 1893.

Fletcher, J. Evidence Before the Select Standing Comminttee on Agriculture and Colonization. Ottawas, 1905, p. 53.

Fletcher, J. Experimental Farms Reports for 1892, p. 148. 1893.

=PLANTS ASSOCIATED WITH THE LOCOED CONDITION.=

The condition known as "locoed" is popularly believed to be due to eating various plants, especially the members of the Astragalus and Aragallus genera of the Leguminosæ, or pea family, but particularly to Astragalus mollissimus and Aragallus lamberti. These plants have therefore received the name "loco plants," or crazy weed. But others, as Astragalus mortoni, A. hornii, A. lentiginosus, A. pattersoni, A. nuttallianus, A. missouriensis, A. lotifloras, A. bisulcatus, A. haydenianus, A. tridactylicus, Crotalaria sagittalis, Lotus americanus, Sophora sericea, Caprioides aureum, Aragallus deflexa, A. campestris, A. lagopus, Malvastrum coccineum, Amaranthus graecizans, and Rhamnus lanceolata, are considered by some as loco plants. In other places Stipa vaseyi, Leucocrinum montanum, Fritillaria pudica, Zygadenus elegans, and even species of Delphinium are considered loco plants, so widely has this name been used.

In Mexico the term "locoed" embraces a condition due to the action of Cannabis sativa and various members of the nightshade family. This term has been much abused and has been made to embrace many groups of symptoms. In fact, if an animal dies while showing more or less stupor it is said to be locoed. The early Spanish settlers seemed to be unfamiliar with the disease, or at least of any causative relation between the plant and the disease. The Spanish name for Astragalus mollissimus was "Garbanzillo," from its resemblance to Garbanzo (Cicer arietinum), which is used in Spain as a food. The term as applied to this condition seems to be of comparatively recent origin.