THE COBALT ENGIMA - SOME OBSERVATIONS AND STRATEGIES FOR OTAGO AND SOUTHLAND

Abstract

The role of cobalt (Co) and vitamin B 12 in animal nutrition is well understood, but the practical questions of predicting when and where a defnency is likely, and the most effective preventive strategy, remain unanswered in Southland and Otago. The incidence of Co deficiency in the region has recently increased, particularly where the problem had not previously been recognised In a long term maintenance Co topdressing experiment at Woodlands Research Station, pasture Co concentrations have been monitored since 1982 and lamb growth measured in two seasons. Cobalt deficiency has been observed only in the two driest seasons. It is postulated that soil manganese may influence the seasonal availability of Co to pasture plants. The effect of Co topdressing on pasture Co levels in the season of application was very short lived. Rate of cobalt sulphate application affected peak pasture concentration but had little effect on the duration of the pasture response. Lambs grazing treated plots did not gain a substantial reserve of vitamin 8, 2 Timing of Co application in relation to the likely period of deficiency is very Important. Keywords: pasture mineral content, lamb growth rate, vitamin B, 2, cobalt