USE OF COBALT SALTS

Nelson Evening Mail, Volume LXXIII, 14 June 1939, Page 9

USE OF COBALT SALTS

FOR OVERCOMING STOCK AILMENTS PROGRESS OF WORK IN CAST YEAR j CAWTIIRON INSTITUTE REPORT A survey of the cobalt content of typical pastures in the South Island has been commenced by the Cawthron Institute and already useful information has been obtained. The annual report of the Institute refers to that section of work as follows : In previous reports mention has been made of the successful use of cobalt j j salts in overcoming stock ailments at , | Glenhope. Nelson, and at Morton Mains. 1 I Southland During the past year in- j i vestigations relating to the use of cobalt i j have been continued at both these cen- ; tres and work lias been established in i j the Sherry River. Nelson, and at Ser- j j geant’s Hill. Westport, where stock ailI ment of the Bush-sickness” type has j i been identified Studies dealing with 1 i the manufacture and use of cobaltised ! fertilisers have been continued, and ! further work lias been done on the seaj tonal variation in the cobalt content of 1 typical Nelson pastures. As a result of a special grant from 1 ; tlie Wool Publicity Committee and the : Meat Board, a survey of the cobalt I content of typical pastures in the South Island has been commenced and already much valuable information lias been obtained concerning the cobalt status of different pasture areas in the South Island PASTURE SURVEYS During the past year pasture sampling for cobalt determinations has been carried oiit in the Sherry-Wangapeka. Westhaven-Collmgwood and Takaka districts of Nelson. On the West Coast pastures have been sampled at Karamea. Westport, Greymouth and at Hoki- ; tika. Surveys of a less detailed nature j have been made in Southland, Ashbur- | ton County. North Canterbury and j Marlborough. i Although cobalt determinations are

not yet available for all the districts which have been sampled, the surveys have already shown several areas to be low in cobalt. Pastures located on tl?e granite-derived soils of the Sherry, Dart and Wangapeka valleys are all tow in cobalt. On these soils the pasture data correlate well with corresponding coball determinations on the soils. In the West haven-Co 11 in gwood districts. the cobalt survey has shown a variation of 0.08 tn 0.08 p.p.m. cobalt for pastures located on sandstone, conglomerates and blown sands. The data correlate well with the known incidence of stock ailment and suggest that cooaJl supplements will prove beneficial to stock over extensive areas of country. On the West Coast the analyses show that pastures located on the Pakihis, on the leached blown sands of Karamea and Westport anrj on the old gravel terraces of the Grcy-Rcefton valley arej all low in cobalt. In view of the excellent results obtained with cobalt supplements on Pakihi pastures, an extensive use of cobalt supplements for stock is indicated for several areas on the West Coast. The results obtained from pastures in the Ashburton County do not suggest any likelihood of cobalt deficiency. In Southland the cobalt determinations have shown considerable variation Samples collected from leached loess soils tend to be low in cobalt, while samples from the more recent alluvial soils are satisfactory. Climatic and seasonal conditions appear to exert an important influence on the cobalt status of the pastures, and much additional work will be required before a clear picture can be obtained of cobalt status in relation to stock health

COBALTISED FERTILISERS Our wo-k on the commercial manu-1 facture of cobaltised fertilisers has been j j continued. Through the courtesy of j ' Messrs Kempthornc and Prosser. Dun- j edin. a new batch of 15 tons of cobalt- I ised superphosphate containing 0 10' per cent, cobalt has been prepared.! Cobalt monoxide was used in the manu- i facture of the cobaltised superphos- ! phate. which on analysis showed over! 90 per cent of the contained cobalt to j be present in a water soluble state I Pasture trials with cobaltised fertilisers have shown their value in increasing the cobalt content of pastures over 1 lengthy periods. Stock grazing previ-! ously unhealthy pastures topdressed m i this way have kept in perfect health, j SEASONAL VARIATION IN COBALT CONTENT OF PASTURES Our studies of the seasonal variation in the cobalt status of typical Nelson , pastures have been continued. During the past year a range in the cobalt i content of 0.06 to 0 44 p p.m. on the dry basis was found. It has not proved possible yet to correlate variations with i meteorological and seasonal conditions. ,

,| ANIMAL TRIALS i Excellent results have been obtain- i „ j ed at Glenhope and at Westport by the j .. iuse of cobalt supplements and cobalt- i I ised fertilisers. At both places com- j i nlete recovery of affected animals was ! ; obtained and live-wegihts showed a ! Phenomenal increase. At Glenhope 1 ! chemical examination of soils, pasture - and animal organs shows that stock ail- ! - ment is caused solely by a deficiency' : of cobalt--the analyses negativing any ; , suggestion of a dual deficiency of cop- : . per and cobalt or of iron and cobalt. At Morion Mains, the past year lias! proved unsatisfactory for field experimental work. The control animals remained free from ailment and the liveweights of the sheep compared favour- , ably with those of the eobalt-treattci i plots. During ihe present season 1928-39, no | symptoms of lamb ailment has been | noticed so far. Cobalt determinations of the pasture show figures of 004 1 p.p.m. which, in other district, have been definitely associated with sheep \ ailment. It is possible that the lambs j , included in this season's experiments | l possessed a greater reserve of cobalt j s which so far has enabled them to make ! normal growth incremnets. * Pasture samples collected from plots j l treated with cobalt salts show a ver> ! >■ satisfactory increase in the cobalt status j r even with as small dressings as J-lb • cobalt chloride equivalent per acre. *