BUSH SICKNESS.

Otago Daily Times, Issue 19615, 20 October 1925, Page 10

BUSH SICKNESS.

BRITISH ASSOCIATION.

ME B. C. ASTON'S PAPER.

VALUE OF NEW ZEALAND RESEARCH.

(Fkom Oub Own Cobbespondent.)

LONDON, September «. Mr B. C. Aston, chemist to the New Zee* land Government, attended the sitting of the Chemical Section of the British Association, and read a paper on what it known aa “Bush Sickness” in New Zealand. Deficiency .diseases in domestic animals came in for a goed deal of attention during the session, and Mr Aston’s paper shed some light on problems that need solution in this country. Iron starvation, said Mr Aston, affected the progress of settlement in a large tract of country in or" near the Thermal district in the North Island of New. Zealand. Ruminant stock would not thrive longer than a few months on the pasture. Their permanent diet, consisting of the usual grasses (cocksfoot, ryegrass, and fescue) and clovers (red, white, and yellow), grew well on the land when the forest was felled and burnt. The existence of the trouble had been recognised for the past 40 years under the local names of "Bush Sickness,” “Bush Disease,*’ or ‘‘the Skinnice.”

Veterinarians had satisfied themselves that the mortality of ruminants which occurred in every case in which the animal was kept long enough on the same land without a change, varying from six months to a year, was not due to any specific organism, that the disease did not spread from one district to another, and that transfusion of blood and inoculation experiments failed to convey the sickness from an unhealthy to a healthy animal. The disease was confined to special areas, and affected cattle rapidly improved in condition and recovered perfectly when removed to what was known to be healthy country.” The absence of any acquired immunity in ruminants, and that horse 8 thrived for yeara upon the same pasture upon which ruminants would sicken and die in a few , months were well authenticated facts. There was also the curious fact that cattle suffering from “the Skinnies” when removed to what was known to be healthy country for some months and then returned still in poor store condition to the farm upon which they became emaciated would then fatten. DEFICIENCY OF IRON.

“The cause of this remarkable mortality,** Mr Aston continued, "which only affects ruminants (goats and deer are reputed to be affected) might be either (X) a deficient element in the food supply, or (2) a poison. The second conjecture is disposed of by the analyses of soil and pasture and animal specimens, which fail to show the presence Of any known mineral poison .tin toxic amounts. The facts that a beast will return after a change and then fatten upon the same pasture upon which it became emaciated, and that horses are. not affected, _ also points to an absence of any mineral poison. Chemical analyses of blood from diseased compared, with that from healthy beasts showed a great deficiency of iron, and this suggested experiments with iron salts on the pasture on which sheep were grazed. The results of these led the speaker to publish, in 1912 the suggestion that a deficiency .of iron in the herbage might be the cause of the disease.

“This proved a workable hypothesis which has largely dictated the experiments instituted since that date, and which for the past 12 years have been continuously carried out on the Government farm in the affected country devoted to finding a practicable remedy for tho disease.” • ' ■ Mr Aston added that in 1919, in conjunction with Dr C. J. Eeakea, he published a Paper on the curative treatment of Bush Sickness with iron salts. In this paper the double citrate of iron and ammonium was > stated to be- the most effective form of iron, and this has been proved by all subsequent experiments. Mir Aston then . detailed the facts that had - been demonstrated in New Zealand by a long series of experiments.

SIMILAR DISEASE IN THE CHEVIOTS. Dr J. B. Orr, Director of the Rowett Institute of Research, Aberdeen, dealt with the importance of mineral Axds in the nutrition of domestic animals, and he specially referred to the work done in New Zealand on ' Bush Sickness " as evidence of iron deficiency. He considered that aeimilar disease was to he found among sheep in the Cheviot Hills.

Colonel H. A. Reid, of the Ministry of Agriculture’s Veterinary Laboratory, followed with some notes on deficiency diseases in New Zealand which he had studied in conjunction with Mr Aston. His results showed that Bush Sickness was a problem for the chemist rather than for the pathologist or bacteriologist. Captain Elliot (Secretary for Scotland in the present Cabinet) quoted from Mr Aston’s paper. It was a remarkable fact, he said, that cattle which were becoming emaciated on bush-sick lands, on being giveh a change to healthy pasture could be retur&ed to their former pasture and would fatten. This showed that the animals had stored up mineral food on the healthy country which was deficient on the unhealthy country. Lord Bledisloe and Sir R. Grigg also referred to the importance of the facta laid before the meeting.