SUMMARY. "Poisoning (of stock) usually does happen often, but seldom is it caused by "weeds." More often it is caused by quite good pasture plants which, in ordinary circumstances of consumption by rested, padlocked animals, form the backbone of the pastures". It is hoped to describe briefly herein sickness and mortality in travelling cattle, the cause of which was due almost certainty to consumption, en route, of a native plant seldom, if ever, eaten by stock in paddocks. Although the evidence against the suspect plant is not conclusive for want of further feeding tests, the following should supply sufficient conviction that Craspedia chrysantha (Benth), or "Yellow Top" or "Billy Buttons," as it is called popularly, is a plant to be avoided by persons in charge of travelling stock, more particularly hungry cattle.
History. Despite the fact that ten thousand cattle had moved southwards over the route into the Deniliquin Pastures Protection District during the preceding nine months, it was not until the last day of September, 1946, that a drover telephoned to report mortality and severe sickness—suspected by him to be "Pleuro" in a herd in his charge just south of Booroorban in the Hay District.
On investigation it was found that of 646 mixed cattle, ranging from vealers to cows eight years old, nine had died without struggling on a night-camp in a north-western corner of the stock route about two miles south of Booroorban.
The herd, in very forward condition and containing newly-born calves, had been watered from a safe public watering place bore while comparatively empty, and then walked a couple of miles over quite bare ground to camp in a corner in which was growing in isolated profusion "Yellow Top" or "Billy Buttons," with very scanty growths of other plants.
Nine beasts were found dead on the morning of 30/9/1946, ages mostly ranging from six months to approximately eight years. The ground under the herd was spotted with hundreds of black patches where beasts had scoured and it was estimated that some thirty per cent of the cattle showed malaise, inappetence, abdominal colic, diuresis and diarrhoea.
There was ample evidence that much of the suspected plant had been grazed; indeed, there was little else available and the animals were hungry on arrival.
Post-Mortem Examination. No significant feature presented other than slight gastro-intestinal irritation and the presence, in the rumen of each carcase, of a preponderance of Craspedia Spp. The animals had been dead for several hours and, from the absence of any sign of agonal struggling, it was evident that the cause of death had been swift and strong.
Among other things ingests and sufficient of the plant for feeding tests were submitted to Glenfield Veterinary Research Station for laboratory examination; the following being taken from the report received:—
"The rumen contents consisted largely of a matted mass of white, woolly, leafy and stemmy material with only about ten per cent. of powdery composition. The following were the identifiable portions: Common: Craspedia chrysantha—Flower heads, leaves and stemmy portions. Fairly Common: Atriplex Spp.—Fruits and leaves; Kochia Spp.—Fruits; Bassia brachyptera—fruits."
"Craspedia chrysantha is known commonly as "Billy Buttons"" and this plant has been under suspicion as the cause of death in cattle and sheep on previous occasions."
"The plant when air-dried was not decomposed or mouldy, and it was, therefore, suitable for feeding experiments. The thick stems were discarded and the remainder, about seven pounds in weight, was chaffed and this was fed to two sheep mixed with wheaten chaff. The plant, however, was distasteful to them. Seven days after feeding commenced one of the sheep showed evidence of nervous disturbance. It stood in a frightened attitude holding the legs stiff and apparently ready to jump away at the sign of any approach to it. When moved it showed considerable excitement and muscular spasms. The head was held erect and there appeared to be some disturbance of vision. The following day the animal was down, unable to rise and was passing a black scour. It was destroyed for post-mortem examination, but no gross lesions were detected."
Although the herd was full of very sick animals, none seemed immediately likely to die. The drover was advised to move them carefully further south on to pure perennial saltbush and control their water intake for some little time. The sickness abated without further loss.
Discussion. It was fortunate that losses totalled merely in the vicinity of one hundred pounds. It is hard to understand why it did not run into two or more thousand pounds as sufficient of the herd were affected severely and the deaths of the few were quite spectacular in the speed with which the causal agent worked and the absence of premonitory symptoms or agonal struggling.
Of the plant genera noticed in the rumenal ingesta most receive but brief mention in the publication of The Poison Plants Committee of New South Wales. Atriplex Spp. contains an emetic; Kochia receives more mention and, apparently, has a quite disturbing effect in some feeding tests; Simla and Craspedia spp. both are suspected of causing mortality. However, with the exception of Craspedia, all are comparatively common among local pastures and stock routes; where they are eaten commonly by stock without ill effects having been reported locally.
Craspedia, on the other hand, is comparatively rare here; no other patch of comparable dimensions being known on the travelling stock routes of this District. It is, moreover, very distasteful and there is no local knowledge of it being grazed naturally.
This plant was preponderantly present in the rumen of each affected animal, any of which must have eaten in the vicinitiy of ten to twenty pounds thereof. Their intake for some twelve hours or more preceding ingestion of this plant was little other than a full drink of water and they grazed the plant greedily to the degree of eating even stemmy portions. Possibly this was a different set-up from factors associated with a feeding test with coastal sheep on a plant some days after collection.
Conclusion. It is difficult to form final conclusions at this stage. However, the presence of bones and old carcases of cattle on the site of the only patch of Craspedia known on the stock routes in this District, this mortality and the statements of old residents thereabouts concerning losses in cattle on this spot over many years certainly lend much confirmation to the belief that this plant should be avoided by driven cattle.
Acknowledgment. The approval of the Department of Agriculture for the publication of matter contained in official reports is acknowledged with thanks: as also is assistance by officers of that Department.
(1) Bray. K.S.F., 1946.—Year Book, Institute of Inspectors of Stock of N.S.W. Long Distance Stock Transport, pp. 74-76.
(2) Bray, K. S. F., 1945.—Year Book as above. Nitrite Poisoning, pp. 39-41.
(3) Hurst, E., 1942.—Poison Plants Committee of New South Wales, The Poison Plants of N.S.W., pp. 91, 97, 307.