Interrelationships among mineral levels in soil, forage, and animal tissues 3. Manganese, iron, and cobalt

Abstract

An experiment was conducted with samples from six farms in northern Mato Grosso, Brazil, to study the interrelationships among levels of minerals in soil and forage and animal tissues during the wet and dry seasons of the year. Soil extractable Mn levels were slightly low (6 and 14 ppm) in two farms, but adequated over 20 ppm in the other four farms. Forage Mn levels were sufficient to meet the requirements of grazing cattle in all six farms. However, liver Mn was deficient on five of the six farms, and during the wet season there was more deficiency than during the dry one. Soil extractable Fe was slightly low for production of some crops in two of the farms, but adequate (over 20 ppm), on the other four farms. High forage Fe on all six farms was sufficient to meet the requirement of grazing beef cattle. Liver Fe levels were normal in all six farms. Soil extractable Co was adequate in the farms 1,3 and 4, and deficient in the other three. Forage Co was adequate in the farms that had also adequate soil Co, and deficient where soil Co was deficient. Liver cobalt was at normal level in all six farms due to the high cobalt supplementation. Liver Co means were lower during the wet season than during the dry season.