Other names given to this weed are British ragwort, tansy-ragwort, staggerwort, and stinking-willie.
The common ragwort is a perennial (or biennial) with short, thick rootstocks. It is sometimes quite woolly or almost devoid of hairs. The stems are stout, simple or branched above, with deeply-lobed and incised green leaves. The flower heads are arranged in a broad, flat-topped cluster, each head bright yellow, in form resembling a small daisy. It is in full bloom from July to September. The seeds are small and easily blown about by the wind.
Ragwort Plate XLI
Ragwort has been introduced from Europe, and is now naturalized in Canada from Newfoundland to Quebec and Ontario. It is found in ballast, along roadsides, in waste places and pastures.
This weed has been the cause of considerable loss among cattle in Canada. At first it was not generally recognized that there was any connection between ragwort and the serious disease of the liver (hepatic cirrhosis) known in Canada as the Pictou cattle disease. The late Dr. Fletcher called attention to this suggestion in 1891. "This plant," he says, "is well known in Pictou county, and it is stated that the majority of the farmers there believe that to it and it alone are they indebted for what is known as the 'Pictou cattle disease.'"
At that time the average yearly loss in Pictou county, Nova Scotia, was 200 head of cattle. The Dominion Department of Agriculture made careful and extensive investigations (1903-6) which proved the weed ragwort to be the cause of the disease. As it was found that sheep were capable of assimilating the plant without injury, it was kept in check by pasturing them on the infested areas.
In South Africa the same disease, locally called Molteno cattle sickness, appeared among horses as well as cattle, and was attributed to a closely allied species of ragwort. In New Zealand considerable attention was given to this disease among horses, under the name of the Winton disease, and a great effort was made to eradicate the weed (Senecio Jacobaea). With this object in view, sheep were pastured on an area of 4,000 acres where ragwort grew very abundantly. Although, in about a year's time, several mortalities among the sheep occurred, Gilruth came to the conclusion that, if the weed is not too prevalent, sheep may, with a few exceptions, graze upon it daily without injury.
In England, recent poisoning (1917) of cattle has been reported (Board of Agriculture) from feeding them on dried forage containing ragwort. In this case, as in others, the feeding had been going on for a considerable period before any visible effects of the poison occurred, showing that the action of the poison is both insidious and cumulative. Little is known of the actively poisonous principle, but it is evidently one or more of the alkaloids which have been isolated from various species of ragwort.
In regard to the cases of poisoning in Canada it was found that the disease was progressive, and to the careful observer certain premonitory symptoms were visible sometimes months before more characteristic manifestations appeared. In one case reported upon by Pethick, by actual experiment which lasted eighteen months and twenty-one days, death occurred only forty-four days after the first visible symptoms. "In this case," he says, "as indeed in nearly all others, we noticed a peculiar bleached appearance of the hair, which seemed to have lost its lustre, a desire to be alone, irritation of temper or nervousness, occasional chills, although in a moderately warm stable. This animal would stand and shiver while the healthy members of the herd appeared comfortable. The bowels are irregular, the pulse at this stage is fast although quite strong, temperature slightly above normal." Later and more characteristic symptoms are: visible mucous membrane pale, eyes amaurotic, slight diarrhoea, emaciation, followed by great weakness, staggering gait, inability to rise, and finally death.
Remedy and Means of Control: Although strychnine and iron may be used in incipient cases with beneficial results, it was shown by these experiments that measures of this kind are of little real value. The best means of controlling the disease is through the eradication of the weed, and for this purpose (Report Veterinary Director-General, 1911), "The farmers in the counties of Pictou and Antigonish, as also those portions of Prince Edward Island where the weed and the disease existed, were strongly advised to make use of sheep as an economical and profitable means of eradicating this troublesome plant. Numerous farmers followed this advice, but many other methods of eradicating ragwort were also inaugurated, while the practice of removing it from the hay when cut was almost universally adopted. As a consequence, loss from the disease has become almost unknown."