Yellow Vetchling (Lathyrus Aphaca L.). To what extent this vetchling is poisonous to stock is not clearly known, but it is cultivated in India as a fodder for cattle. The seeds, however, are not altogether safe when ripe, and MacDougall says “The seeds and pods have been known to be used in soup in their young state and without harm resulting, but the ripe seeds are narcotic and cause sickness and headache.”
Lupines (Lupinus sp.). Different species of Lupinus have been found to cause poisoning of live stock, more particularly sheep, which, when fed largely on lupines, develop a chronic type of poisoning known as Lupinosis, or poisoning may be acute and rapid in its effects, as in the United States. Records of large numbers of sheep being affected at a time date from 1872, in various parts of the German empire. In Europe by far the most harmful species is the Yellow Lupine (L. luteus), which has been the cause of heavy losses of sheep, though horses, cattle and goats may also be affected. The Blue Lupine (L. angustifolius) and White Lupine (L. albus) may also be toxic. L. luteus has caused lupinosis in Germany since 1860, and Cornevin states that in 1880 no less than 14,138 out of 240,000 sheep fed upon it (or 5·89 per cent.) died. Of 44 horses affected 11 died.
It must not be thought that all crops of lupine are poisonous, as lupines are extensively grown on the Continent for fodder purposes and are usually harmless. Even where Lupinosis occurs, considerable quantities of the lupine must be ingested to cause poisoning. The toxicity appears to vary according to soil and certain indefinite conditions, and sometimes even a kilogramme (2·2 lb.) of the plant would suffice to kill a sheep. Poisonous symptoms may sometimes be observed after a single meal. Desiccation does not render the plant innocuous, the seeds and hay being poisonous.
In the United States species of Lupinus have caused great loss. In 1898 no fewer than 1,150 of a flock of 2,500 sheep died from eating one species; one sheep farmer lost 700 sheep from the same cause; and 1,900 out of 3,000 sheep died from Lupine poisoning in Montana in 1900. Lupine hay is found to be less harmful to horses and cattle, and Chesnut and Wilcox suggest that this is possibly because as a rule they avoid the pods, while sheep eat them. Lupines in America are very rapid in their action on sheep, which may often die in one-half to three-quarters of an hour after eating a quantity of the pods. Further, there is evidence that sheep may gradually become immune to the poison by eating Lupines regularly, since sheep fed regularly on hay nearly half lupine were unaffected, but others eating the same hay for the first time died in considerable numbers. The lupines are certainly far the most dangerous when they bear ripe seeds—cut and made into hay before the pods form they are much less dangerous.
In regard to L. luteus Lander says: “According to the German authorities a daily ration of 1 pound of the whole plant, ⅗ pound of empty pods, or 1⅕ pound of seeds, will produce poisoning.”
Various means have been tried to render Lupines harmless, and success is stated to follow heating with steam under a pressure of 2 to 2½ atmospheres.
Toxic Principle. A very full account of Lupine poisoning is given by Pott, and from this a brief summary may be made. Siewert and Wildt (1879) found two substances very like the alkaloids of Conium maculatum—one like Coniine and the other like Conhydrine, the former only being proved to be very poisonous. Baumert states that in L. luteus there are only two bitter alkaloids, Lupinine (C10H19ON) and Lupinidine = Sparteine (C15H26N2). Many investigators (e.g. Kühn at Halle) held that lupinosis was not identified with the presence of lupine alkaloids. Then, in 1883, Arnold and Schneidemühl caused the disease (lupinosis) in sheep with lupines freed from all alkaloids, and they isolated from the seeds a substance they named Lupinotoxin, which they found to be poisonous. The nature of the poison cannot yet be said to be fully understood. The Lupine does not always appear to be poisonous—only under certain conditions which are not too well defined. One farmer had Lupines on the same soil for twelve years without ill effects when fed to sheep, and then of 450 sheep 120 were severely ill, and 80 died; they had had unthrashed Lupine, not quite ripe, to the extent of one-fourth of the ration. It is held to be definitely established that the presence of this poison is due in turn to the presence of a saprophytic fungus; when the fungus is absent or only present in small quantity the lupine is not at all or only slightly poisonous.
Symptoms. The disease is either acute or chronic according to the amount of poison ingested. Most writers describe the disease in sheep, but symptoms given vary somewhat.
In the acute form sheep become ill suddenly. There is loss of appetite, dyspnœa, intense fever, hæmaturia, circulatory and digestive troubles, grinding of teeth and trembling, which may pass into spasmodic contractions. Vertigo is sometimes present. Jaundice then appears and is evidenced by the yellow colour of the mucous membranes. Tumefaction of the eyelids, lips and ears is common, but not invariably present. Micturition is frequent, but not abundant, and the urine contains albumen; the excrements are few and dry. There is collapse, and loss of condition progresses rapidly, death occurring on the fourth to the sixth day after the commencement of the illness.
In the chronic form the interstitial hepatitis predominates. Tumefaction of the head may also appear as in the acute form. Digestive troubles indicate chronic gastro-enteritis. This condition lasts for from 15 to 20 days, during which the cephalic œdemæ are eliminated by gangrene and the animals remain listless and without appetite. The illness in sheep is grave, and affected animals are rarely completely cured. The mortality in other species does not seem to be less than in sheep. (Cornevin.)