Intake and excretion of cadmium in sheep fed fresh herbage

N.D. Grace; J.R. Rounce, J. Lee

AgResearch, Grasslands, Private Bag 11008, Palmerston North, New Zealand

Proceedings of the New Zealand Society of Animal Production. 1993, 53: 251-254

Nine Romney sheep fed fresh herbages were used to study cadmium (Cd) metabolism. The major route for the excretion of ingested Cd is the faeces with less than 0.5 percent being lost in the urine. Although there was a marked net secretion of Cd into the digestive tract post duodenually a considerable net absorption occurred from the intestinal region. Absorbed Cd is mainly accumulated in the liver and kidney (>340 ng/g fresh tissue) with much small amounts being associated with muscle (<20 ng/g fresh tissue). As the variation in the intake and excretion of Cd is large, short term balance studies are less suitable as an approach to determine the rate of apparent retention of Cd in grazing animals. The use of long term slaughter techniques and kinetic studies using stable isotopes of Cd are discussed as the preferred methods to measure the absorption and retention of Cd.

Keywords: NZSAPAB; Cadmium; tissue accumulation; kidney; liver; sheep; fresh herbage.

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Last Updated 25-01-1997