This section is from the book "A Guide To The Poisonous Plants And Weed Seeds Of Canada And The Northern United States", by Robert Boyd Thomson, H. B. Sifton. Also available from Amazon: A guide to the poisonous plants and weed seeds of Canada and the northern United States.
Other Common Names: Wild Pea, Wild Bean, Blue Pea, Blue Bean, Pea Vine.
In the west, where Lupines are very plentiful, their misuse as pasture and hay has been the cause of immense losses. Chesnut and Wilcox have enumerated a long list of casualties in Montana. Two hundred sheep were being moved, and were allowed to feed on a patch of Lupine. By next morning one hundred of the band were dead. Lupine hay was fed to one hundred and fifty bucks and as a result of one feed ninety died. Three two-year-old colts were fed ordinary hay most of the winter and then ate Lupine hay for two days, when all died.
Examples and Conditions of Poisoning
In October, 1898, a snow storm covered the grass, and out of a band of 2,500 sheep, 1,150 died from eating the Lupines. During the winter of 1898-99 about 7,000 sheep in Montana were poisoned by Lupine hay, and of these over 3,600 died. Many more cases of a similar nature are recorded, and the evidence leaves no room for doubt as to the cause of death. In all cases the Lupines eaten bore pods containing mature or nearly mature seed.
Fig. 7. - Common Lupine - Lupinus perennis.
The experiments of Marsh, Clawson and Marsh, taken along with those of other investigators, have established the fact that poisoning in this country is due almost exclusively to alkaloids, which are contained in all parts of the plant, but are more abundant in the seed. The toxic dose of these alkaloids is very nearly as large as the fatal dose, and smaller quantities have little or no effect on the animals. It thus happens that Lupines and Lupine hay containing no seeds may be wholesome and satisfactory as a feed, while plants with full pods are deadly poison. It has been established that the poison acts on horses, pigs, goats and cattle, as well as sheep. Cattle on the range usually leave the pods and so are rarely poisoned, but sheep eat them greedily.
The general symptoms of poisoning in the early stages are cerebral congestion and great excitement: in experiments with sheep this showed itself by their rushing about and butting and pushing. Later the movements become irregular and incoordinated, with spasms and falling fits. When the animal can no longer stay on its feet, convulsions like those caused by strychnin are often evident. The excretions of the kidneys are increased and are sometimes bloody. The immediate cause of death is usually respiratory paralysis, which ordinarily ensues in a half to one and a half hours. Sometimes in milder cases the animals live four or five days In these cases the respiration becomes slow and laboured, the pulse is weak and the animals fall into a state of coma.
In horses there are certain special symptoms: dullness, contractions of the surface muscles, intestinal disturbances, usually manifesting themselves in constipation, but sometimes in diarrhoea. There is also a tendency to lift the forefoot high in walking.
The results of the search for antidotes have not been very satisfactory. Permanganate of potash has been recommended, but is useless unless given very early in the course of the attack. Vinegar and dilute sulphuric acid are also spoken of as chemical antidotes. Hypodermic injections of such sedatives as mor-phin or chloral hydrate are useful in controlling the convulsions.
According to Marsh, Clawson and Marsh: "There seems to be little doubt that, as in Zygadenus poisoning, if sodium bicarbonate can be administered at intervals frequent enough to catch the toxic principle as it enters the fourth stomach, recovery may be aided. This is of considerable theoretical interest, and the method might be used in order to save an especially valuable animal, but of course range animals cannot be treated in this way."
In Europe a species of Lupine, Lupinus luteus, has caused trouble, producing a disease called Lupinosis. Investigation shows this plant to be much poorer in alkaloids than our American species, and the symptoms of Lupinosis differ from those described above. There is loss of appetite, weakness and fever in the early stages. Acute atrophy of the liver is usual, giving rise to a yellow colour in the conjunctiva, mucous membranes and body tissues. In some cases the ears, eyelids, lips and nose swell. In addition there is cerebral excitement, gnashing of the teeth, pain in the posterior region of the body, diarrhoea, and sometimes blood, bile and albumen in the urine. This disease is supposed to be caused by a substance to which the name ictrogen has been given. It is believed that ictrogen is produced by micro-organisms living on the Lupine leaves, and this theory is strengthened by the fact that while Lupines in some fields produce the disease, those of the same species in other locations are harmless. Lupinosis is very rare in America if, indeed, it ever occurs here. Dr. A. D. Knowles of Butte, Montana, had cases where some of the symptoms were present in horses.
In eastern North America only a few species of Lupine are found, L. perennis being most common, but in the west they are very plentiful. Rydberg lists eighty species from the plains and mountains. They grow most frequently on dry hillsides and are often cut for hay. When fed to animals it is essential that no seeds be included.
They grow in tufts from a perennial root, and are easily recognized by the more or less wheel-shaped, pal-mately compound leaves, of entire, oblanceolate leaflets-The purple or whitish pea-shaped flowers are in loose spikes. The keel of the flower is scythe-shaped and pointed, and the filaments of the stamens are united to form a complete sheath about the ovary. The anthers are alternately oblong and roundish. The pod resembles that of the pea, and is often knotted by constrictions between the seeds.
Lupines are easily eradicated by cultivation, but their destruction in uncultivated land is impracticable where they are present in quantity.
White Snakeroot, Eupatorium urticaefolium Reich-ard, and its symptoms are described among the harmful pasture plants, as it is in pasture that it causes most trouble. Its poisonous properties are not destroyed by drying, however, and the disease "trembles" is produced by hay in which White Snakeroot is included. (See p. 85).