No effect of copper dosing on the growth and vitamin B₁₂ status of grazing cobalt-deficient and cobalt-dosed lambs

Abstract

Extract

Although copper deficiency disease causing ataxia in lambs has been of common occurrence in this and other countries, there is not, to the writers' knowledge, any incontrovertible published evidence that copper supplements will improve the growth rates of copper-deficient sheep. However, some New Zealand experience has suggested that copper might have a beneficial effect on the growth of lambs that are cobalt-deficient. Thus, on a farm near Apiti (Pohangina County), G. F. Sommerville (pers. comm.) obtained a marked statistically-significant liveweight response to cobalt “bullets”, and a small though non-significant difference in favour of copper-injected as compared with untreated lambs. Analysis of pasture and liver samples from two small areas were suggestive of a dual deficiency of copper and cobalt at Pakipaki, Hawke's Bay, in the North Island (Cunningham and Laing, 1957), and at Waikari, North Canterbury, in the South Island (I. J. Cunningham, pers. comm.). Ataxia in lambs was not a known feature in either area but in both, cobalt deficiency was confirmed by weight responses of lambs to cobalt dosing, and in both, experimental results indicated possible weight responses to orally-dosed copper. Furthermore, Russian workers (Koval'skii and Raetskaya, 1955) have reported that a copper sulphate supplement given to cobalt deficient sheep increased the deposition of vitamin B₁₂ in liver.