Barium, A Cause of the Loco-Weed Disease Part 3

[51] Nockolds, C. Poisoning by Loco Weed. Amer. Vet. Rev., vol. 20, p. 570. 1896-7.

[52] Stalker, M., l. c., p. 273.

[53] Stalker, M., l. c., p. 274.

[54] Ruedi, C. Loco Weed (Astragalus Mollissimus): A Toxico-Chemical Study. Trans. Colo. State Med. Soc., 1895, p.

417.

[55] Blankinship, J. W. Loco and Some Other Poisonous Plants in Montana. Mont. Agric. Exper. Sta. Bul. 45, p. 81. 1903.

[56] Blankinship, J. W., l. c.

[57] Day, M. G. Loco-Weed. In F. P. Foster's Reference Book of Practical Therapeutics, vol. 1, p. 588. 1896.--Pilgrim, C.

W. Does the Loco-Weed Produce Insanity? Proc. Amer.

Medico-Psycholog. a.s.soc., vol. 5, p. 167. 1898.

[58] Schuchardt, B. Die Loco-Krankheit der Pferde und des Rindviehs. Deutsch. Zeits. f. Thiermed., vol. 18, p. 405.

1892.--Parker, W. T. Loco-Weed. Science, vol. 23, p. 101.

1894.

[59] McCullaugh, F. A. Locoed Horses. Journ. Comp. Med. and Vet. Archives, vol. 13, p. 435. 1892.

[60] Stalker, M. The "Loco" Plant and Its Effect on Animals.

Bur. Animal Industry, 3d Ann. Rept. (1886), p. 272. 1887.

[61] Stalker, M. The "Loco" Plant and Its Effect on Animals.

Bur. Animal Industry, 3d Ann. Rept. (1886), p. 272.

1887.--See also Linfield, F. B. Sheep Feeding, in Mont.

Agric. Coll. Exper. Sta. Bul., 59. 1905.--Special Report on Diseases of Cattle. Bur. Animal Industry, 1904, p.

66.--Wilc.o.x, E. V. Plant Poisoning of Stock in Montana. Bur.

Animal Industry, 17th Ann. Rept., p. 115. 1900.

[62] Stalker, M., l. c., p. 275.

=CONDITIONS SIMILAR TO LOCO-WEED POISONING IN OTHER PARTS OF THE WORLD.=

According to Maiden[63] a condition similar to loco is met with among animals in Australia and is there believed to be due to eating various species of Swainsona.[64] As Maiden says, "Its effect on sheep is well known; they separate from the flock, wander about listlessly, and are known to the shepherds as 'pea-eaters' or 'indigo-eaters.' When once a sheep takes to eating this plant it seldom or never fattens, and may be said to be lost to its owner." Horses, after eating this herb, "were exceptionally difficult to catch, and it was observed how strange they appeared. Their eyes were staring out of their heads and they were prancing against trees and stumps. The second day two out of nine died, and five others had to be left at the camp."

Martin[65] experimentally studied these cases of intoxication and sums up his work as follows:

1. That one can by feeding sheep upon Darling pea reproduce all the symptoms which are attributed by pastoralists to this cause.

Briefly stated these symptoms are: Stupidity, loss of alertness and an agonized expression, followed by stiffness and slight staggering and frequently trembling of the head or limbs. Later, clumsiness and unsteadiness ensue, which slowly advance until the animal often falls down. In this stage, the action of the animal in running over small obstacles is characteristic. It jumps over a twig as if it were a foot in height. When first it commences to tumble about, it is able more or less readily to regain its feet, but in the advanced stage of the disease this is impossible and, after exhausting itself in efforts to do so, it remains lying down until it dies. During the whole time the sheep become progressively more bloodless, and in advanced cases the blood when shed appears to the naked eye lighter in color. It contains fewer red blood-cells (about two-thirds to one-half the usual number). (The corpuscles were estimated in several cases by means of a haemocytometer.) All these symptoms are much aggravated by driving. Thus, an animal in which the symptoms are little marked may exhibit them in a striking degree after being driven. In addition to the above the teeth (especially in young sheep) frequently become loose, and consequently displaced or even dislodged.

2. That the time which elapses before the onset of definite symptoms is three to four weeks in sheep of 2 to 3 years old. (It is probable, however, that with younger animals the time is shorter.)

3. That under the conditions of the experiment, the animals survived about three months. They lived, however, an invalid's life. Everything was brought to them, and it is improbable that if feeding exclusively upon the pea, and left to shift for themselves in the paddocks, they would survive more than two months.

4. That if a sheep be returned to proper fodder after one month to six weeks feeding upon the pea, and before the symptoms are fully established, it may recover completely.

5. That when once the paralytic symptoms are established it will not recover; but if returned to proper food, will remain in much the same condition, becoming neither better nor worse.

6. That Darling pea contains a very fair amount of nourishing material so that animals may, provided they eat it readily, retain their condition on it for some weeks, until the poisonous principle contained has had time to exert its effects.

These plants, if fed with other herbage, do not seem to be injurious and apparently lose their harmful action upon being cultivated.[66] As long as salt is properly fed the animals will not eat this plant[67] and are said to suffer no effects from it. Physiological study has shown the presence of a body with marked sudorific power which causes rapid emaciation in frogs.[68]

It has been claimed that these symptoms are due to the presence of a narcotic poison in the plant.[69] Post-mortem examinations were negative save for the presence of a peripheral neuritis.[70]

FOOTNOTES:

[63] Maiden, J. H. Plants Reputed to be Poisonous to Stock in Australia. Dept. Agric., New South Wales, Misc. Pub. No. 477, pp. 15, 16. 1901.

[64] Notes on Some American and Australian Plants Injurious to Stock. Agric. Gaz., New South Wales, vol. 4, p. 677.

1894.--Notes on Weeds. The Darling Pea. Agric. Gaz., New South Wales, vol. 3, p. 330. 1893.

[65] Martin, C. J. Report on an Investigation into the Effects of Darling Pea (Swainsona Galegifolia) upon Sheep.

Agric. Gaz., New South Wales, vol. 8, p. 366. 1898.

[66] Woolls, W. On the Forage-Plants Indigenous in New South Wales. Linn. Soc., New South Wales, Proc., vol. 7, pp.

315-316. 1882.

[67] Guthrie, F. B., and Turner, F. Supposed Poisonous Plant.

Agric. Gaz., New South Wales, vol. 4, p. 86. 1894.

[68] Bailey, F. M., and Gordon, P. R. Plants Reputed Poisonous and Injurious to Stock, Brisbane, 1887, p. 25.

[69] Guthrie, F. B., and Turner, F. Supposed Poisonous Plant.

Agric. Gaz., New South Wales, vol. 4, p. 87. 1894.

[70] Martin, C. J. Report on the Investigation into the Effects of Darling Pea (Swainsona Galegifolia) upon Sheep.

Agric. Gaz., New South Wales, vol. 8, p. 367. 1898. (Further literature on the indigo disease will be found in Bailey, F.

M., and Gordon, P. R. Plants Reputed Poisonous and Injurious to Stock, Brisbane, 1887, p. 25).

NOTE.--In Canada a chronic disease a.s.sociated with cirrhosis of the liver results from eating ragwort, or _Senecio jacobaea_. See Dept. of Agriculture, Canada, Rept. of Veterinary Director General, 1905, Ottawa, 1906, p. 31.--In South Africa a disorder known as nenta appears in goats after eating certain plants, especially _Cotyledon ventricosa_. See Hutcheon, D., Nenta, in Agric. Journ. Cape of Good Hope, vol.

14, p. 862. 1899.

=PATHOLOGICAL CONDITIONS IN LOCOED ANIMALS AS DESCRIBED ON THE RANGE.=

The pathological features as described by previous writers are a softening and ulceration of the stomach walls[71] and a degeneration of the walls of the intestines with or without perforations. The peritoneum may be found inflamed.[72] The peritoneum and omentum in one case (cow), reported by Sayre, were covered with small nodules. These were probably tubercular in origin. The colon in one horse was found enormously distended, while the coec.u.m and small intestines were normal,[73] save that the walls appeared thin.