ARCHIVE FILE
This article was published in 1956
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INSTITUTE OF INSPECTORS OF STOCK OF N.S.W. YEAR BOOK.
ARSENICAL POISONING IN STOCK
J. M. WILSON, B.V.Sc., Inspector of Stock, Casino.
The Casino Pastures Protection District is situated within the Tick Quarantine Area, and for many years cattle have undergone regular dipping in an arsenical solution in order to control infestation with the Cattle Tick (Boophilus microplus). Although a large section of the Quarantine Area is now undergoing an eradication campaign using dips charged with D.D.T., dips in the remainder of the area are still charged with arsenic.
From time to time, accidental cases of arsenical poisoning have occurred in cattle as a sequel to dipping. All suspected cases of this nature are investigated by the Board of Tick Control, which maintains an analytical laboratory at Lismore. Where genuine claims are established, compensation is paid to owners in respect of stock lost through dipping. However, in many instances, stockowners adopt a hostile attitude to controls enforced under the Stock Diseases Act, and automatically blame the Department of Agriculture for any stock losses. Claims of this nature, after investigation, are refused.
Many owners will not admit that there are other sources of arsenic apart from the dip, but the author has encountered several instances of poisoning where it has not been possible to incriminate dipping. Futhermore, in these cases it usually is possible after some investigation to determine the actual source of the arsenic.
It is proposed to describe two such cases of arsenical poisoning in cattle
CASE A.
An owner telephoned and advised that in the previous 24 hours, five Jersey cows had died and another four appeared likely to succumb. Within an hour of receiving the above information, the farm was visited; when it was found that a further cow had died. Another was destroyed in extremis, and little hope was held for the remaining two sick animals.
SYMPTOMS: The first symptom noted by the owner was the sudden onset of severe distress, with staggering, muscular trembling, standing with arched back and groaning. Within two hours of onset, affected animals went down. There was rapid respiration, excessive salivation and bellowing. Death occurred within 4 hours of onset, and was accompanied by violent struggling; and in two instances by vomiting. There was no evidence of diarrhoea.
Post-mortem: Examinations were carried out on three animals; all being in good condition at the time of death. The chief findings were pale, swollen, fatty livers, with acute hyperaemia of the abomasal and duodenal mucosaa; while in one case free blood was present in the abomasum. Jejunum and ileum showed a moderate degree of hyperaemia and the mucosal lining stripped easily. Intestinal contents were very fluid.
Specimens were forwarded to the laboratory for examination, and included stomach and bowel contents, unpreserved liver, kidney and abomasal wall.
DIAGNOSIS: The sudden onset of the condition, the symptoms and post-mortem findings were highly suggestive of the recent ingestion of a large dose of some inorganic poison, most probably arsenic. There was no history of recent dipping or access to dipping fluid, but it was noticed that there was a small banana plantation on the property. It was known that arsenic pentoxide is widely used as an adjunct to banana culture, and accordingly enquiries were made in that direction. The owner then revealed that some four days previously he had dismantled an old banana packing shed. No arsenic pentoxide had been stored in this shed for 3 years, but prior to that large quantities of this chemical had been stored therein. It was admitted also that after the shed was dismantled, many of the herd had congregated in the vicinity.
The Director of Veterinary Research reported that "significant quantities of arsenic were found in the tissues".
It seems reasonable to postulate that during the time the shed was used to store arsenicals there was contamination to the underlying ground, which was protected from any effects of weather. On dismantling of the shed, a highly arsenic-contaminated area was made available to the herd.
A more positive indication of the source of arsenic would have been to submit soil samples for analysis. However, it is noteworthy that after the owner had fenced off the suspected area, there were no further mortalities.
CASE B.
An owner reported that two Jersey cows died the previous evening shortly after milking. At the morning milking both animals had been in apparently good health.
SYMPTOMS: The owner stated that on bringing the cows into the yard for the evening milking, both had shown restlessness and apparent discomfort, This was followed in a few minutes by the onset of acute abdominal pain, with groaning, getting up and lying down, and apparent mania and visual deficiency. Profuse watery diarrhoea followed, and both cows finally went down and died within fifty yards of the bails. Death was accompanied by convulsions, and occurred within 4 hours of the onset of symptoms.
Post-mortem: Examination revealed acute hyperaemia of abomasal mucosa and the first portion of the small intestine. Free blood was present in the abomasum, and gut contents were very fluid. The liver was fatty with small pale areas of necrosis, and small haemorrhagic lesions were found throughout the kidney tissue. Sub-endocardial haemorrhage also was present.
Specimens forwarded to Glenfield included stomach contents, and fresh abomasum, liver and kidney tissue.
DIAGNOSIS: The symptoms and post-mortem findings were highly suggestive or arsenical poisoning. The owner stated that there had been no access to arsenic, but stated that he had been spraying weeds with a "safe" weedicide. Apparently the owner had not bothered to read the label on the weedicide drum, which indicated that the preparation was almost 100 per cent. arsenic pentoxide. Further enquiry elicited the fact that the cattle which had died always had grazed away from the herd, and had on several occasions been seen in the vicinity of the arsenic contaminated weeds.
Subsequently the diagnosis was confirmed by the Director of Veterinary Research, who reported that ingesta had given a positive Reinsch test, and that all tissues had a high arsenic content on analysis.
CONCLUSION: The cases cited above are typical of many seen in this District. As previously stated, many owners are inclined to blame dipping for such mortalities. However, in most instances it can be demonstrated that trouble could have been avoided by the exercise of a little forethought on the part of the owner.