STOCK POISONING

Timaru Herald, Volume CXXXVII, Issue 19578, 26 August 1933, Page 5

STOCK POISONING

DANGEROUS METALS PRECAUTIONARY MEASURES Cases have occurred in various parts of the Dominion of stock, frequently dairy stock, dying or becoming seriously ill through metallic poisoning. Many farmers are unaware of the possibility of metal poisoning. Among inorganic materials responsible for the occasional poisoning of live stock, lead occupies an important place. The compounds of this element which most frequently causes trouble are white lead and lead arsenate. The former, a basic carbonate, is the wellknown pigment, and poisoning by the ingestion of lead paint has been recorded many times. If white lead has been left within reach of animals it may actually be eaten from the tin, but it is more usually absorbed by the licking of newly-painted surfaces or the chewing of old painted material. The flaking of paint from the interior of a bucket used for feeding young stock has been known to result in lead poisoning. Lead arsenate, the standard insecticide for leaf-eating pests, is used by the ton in fruit-growing areas. It is a dangerous stock poison which has caused trouble on many occasions. Lead sulphate and alena (lead sulphide) are relatively insoluble in water, but dissolve t® an appreciable extent in the digestive fluids, and are capable of serious damage. It is pointed out by Brynmor Thomas, M.Sc., A.1.C., of Armstrong College, Newcastle-on-Xyne, that the fact has been established that poisoning may result from the taking in of metallic lead. In lead mining areas the soil, herbage, and water supplies may be impregnated with the metal. Not only is the fertility of contaminated land seriously affected, but stock grazing it commonly suffer from chronic lead poisoning. Bullet splashes picked up on rifle ranges have been known to kill grazing stock. It is probable that corrosion of the metal by weathering usually produces compounds which are readily absorbed, but lumps of lead may actually be lodged in the digestive system and corrode there under the influences of the juices. Arsenic is Dangerous. Writing in the “Scottish Farmer/’ Mr. Thomas indicates that arsenic, which goes on to most farms in the form of sheep dip, vermin poisons, weed killers, medicinal preparations, and spraying materials, is equally as dangerous as lead. But“ when arsenical poisoning does occur it is usually accidental, and due either to gross carelessness in.the handling of arseniccontaining materials or in the disposal of dip waste. The uniformed use of condition powders by horsemen occasionally leads to trouble.” In the leadmining areas of the west and southwest of England, arsenical poisoning is sometimes coincident with plumbism, and is similarly acquired by the consumption of contaminated grass and water. Phosphorous poisoning, when it occurs on the farm, is almost invariably due .to the careless use of those rat poisons which contain the finely divided element mixed with a greasy base which retards oxidation and prevents spontaneous combustion. Poultry and other small live stock are frequently killed by such preparations. A very unusual case of phosphorous poisoning which involved heavy losses among sheep was reported some time ago. The affected sheep were grazing on gun practice ranges, and there was good evidence to show that the phosphorus had been derived from smoke shells. Mr Thomas states that only white phosphorus is of any importance in veterinary toxicology, and its deadliness is largely dependent on fineness of division.) / Considerable pieces may sometimes pass through the alimentary canal without exerting any harmful effect. Red or amorphous phosphorus is reputed to be non-toxic, and derivatives of the element, though often highly poisonous, are seldom or never accessible on the farm! Inorganic Poisons Antimony, barium,' and copper are inorganic poisons of relatively slight importance, although they are responsible for stock losses on occasion. The first is used as the sulphide in condition powders, and the. second, as barium carbonate, is often a constituent of vermin killers. Copper compounds find a number of uses in agricultural practice, but they cannot be classed amongst the most dangerous poisons handled by the farmer. Authenticated cases of poisoning arising from the consumption of grain pickled with copper sulphate have been recorded, and the dry bordeaux mixtures used against potato “blight” are reputed to damage horses when applied in any breath of wind.

It not infrequently happens that injury to farm animals is caused by materials which are not poisonous in the proper sense of the term, but which kill by exercising a purely mechanical effect analogous to that of ground glass. Mr Thomas mentions that serious losses have been reported as the result of turning sheep on to grass recently dressed with ground mineral phosphate. It cannot be said that the evidence has been invariably satisfactory, but there is no doubt that the ingestion of considerable quantities of hard and insoluble mineral matter can and does produce acute inflammation of stomach and intestines, which is often followed by fatal results. The possible danger from mineral phosphates can be obviated by keeping stock off the treated pasture until the foliage has been cleared by a shower of rain. Basic slag has a less evil reputation; presumably on account of their greater weight, the particles reach the ground almost immediately, and there is little tendency for the foliage to be contaminated.