ANIMAL HEALTH

Evening Post, Volume CXXI, Issue 142, 17 June 1936, Page 19

ANIMAL HEALTH

VALUE OF COBALT STRIKING EXPERIMENTS $Some remarkable results which indicate the important role played by cobalt'in the health of sheep have been obtained from experiments made recently at Nelson and in Southland. A deficiency of cobalt in the diet, it would appear, is one of the causes of ailments which affect livestock. Where this deficiency has been rectified, a striking improvement in the health of the animals has been observed. At Glenhope, Nelson, and Morton Mains, Southland, stock ailments occur which have some features in common with the well-known "bush sickness" which occurs in the North Island. The Department of Scientific and Industrial Research and Cawthron Institute working in co-operation have for some time past been engaged in an investigation of these diseases, and the workers have now arrived at some important conclusions in regard to the role of cobalt in controlling sickness in sheep in the above localities. In the North Island, limonite is being successfully used in the control of bushsickness, but certain limonites when used in drench form at Glenhope did not prevent sickness from developing. Nelson soil, however, when administered' in small quantities in the form of a drench, was completely successful in preventing any symptom of sickness. Furthermore, an acid extract of Nelson soil, very low in iron, was equally successful in preventing sickness. If was therefore • concluded on these and on other grounds that the beneficial properties of Nelson soil were due to constituents other than iron. In . Southland, Nelson soil and soil from the Bluff, Invercargill, were also effective in preventing the onset of sickness in lambs at Morton Mains, Southland. It appeared probable, therefore, that the same element or elements were/effective in preventing sickness in both Nelson and Southland. Following on the publication by Australian workers of the value of cobalt in the treatment of "Coast" diseiase in South Australia and enzootic marasmus in''Western Australia, it was decided to test the efficiency of cobalt at Glenhope and Morton Mains, The experiments at both places have been remarkably successful, and point definitely to the conclusion that the potent element in the case of Nelson and Bluff soils and of other'materials found helpful in the treatment of bushi sickness is cobalt. In the Glenhope experiments on sheep which were running on a bushsick pasture 1 : the. control sheep which received no drench' steadily lost weight, while those, dreiiched weekly with 8 milligrams little over onetenth of a grain) of cobalt in the form of its chloride made steady increases in weight, the average weight of the cobalt sheep being practically double that of the controls. The accompany-

t ing photograph shows the effect of the I cobalt treatment in a striking way, the 3 sheep on the left being one from the E group drenched with cobalt, and that t on the right one from the group which • received no drench. The woolt growth of the undrenched sheep was ; poor, the wool being dry and lustre- > less, with relatively little crimping; : the wool-growth of the cobalt-drenched r sheep, on the other hand, was very - good, the wool itself being lustrous > and well crimped. It is obvious, therefore, that if' similar results can be obtained in other areas affected by stock sickness, a grc\t economic benet fit to New Zealand will result. In the > Southland experiments similar results £ were obtained, and it was found that . weekly supplements containing as ■ little as, 0.29 milligram '(approximately t four-thousandths of a'grain) of cobalt • were effective in improving stock ■ health. From the available data it is s not yet possible to state what is the 1 optimum amount of cobalt requiijed. 1 This will probably vary according to ' the health of the sheep and their • previous history, while seasonal varia- '■ tions, the state of the pasture, and loca- : tion may all influence the amount of ■ cobalt needed to maintain lambs in i good condition. i The fact that different cobaltcontaining materials have proved ef- ' fective in overcoming these ailments i suggests that the cobalt supplements s are required to meet a definite de- • ficiency of this element in trie diet of stock. It must be admitted, however, that no definite statement. on this point of ; deficiency can at present be made, but ' cobalt is 'definitely a palliative. Analyses of bush-sick soils in various parts of New Zealand show that they contain less than one part per million of available cobalt, . while healthy soils from Hawke's Bay and elsewherecontain available amounts of the order of seven parts per million. At the suggestion of the recent conference on Animal Health a cobalt survey of New Zealand soils, pastures, and animals' organs is at present in progress, and may be expected to supply vital information concerning the role of this element in animal health.