Deposits on rumen epithelium associated with ingestion of soil

Three groups of newly weaned lambs, housed indoors, were fed respectively: control diet; control diet + 50 g Egmont soil per day; control diet + 50 g Papakauri soil per day. At the end of the lO-week experiment it was found that the rumen epithelium of the control animals was cream or light grey in colour and that of animals receiving soil was dark grey to black. The deposit on the epithelium appeared to be precipitated material rather than particulate matter of soil origin. This dark grey to black deposit noted in animals receiving soil was removed by treatment with 6N HCI and shown to contain P, Ca, Fc, AI, Mg, Mn, and Ti.