Effects of cadmium in herbage on the apparent absorption of elements by sheep in comparison with inorganic cadmium added to their diet

Journal Article · Sat Oct 01 04:00:00 EDT 2005 · Environmental Research

DOI:https://doi.org/10.1016/j.envres.2004.12.013· OSTI ID:20698402

Phillips, C J.C. . ^[1]; Chiy, P C ^[2]; Zachou, E ^[3]

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1. Department of Clinical Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES (United Kingdom) and School of Agricultural and Forest Sciences, University of Wales, Bangor LL57 2UW (United Kingdom) and Centre for Animal Welfare and Ethics, School of Veterinary Science, University of Queensland, Gatton, Queensland 4343 (Australia)
2. Department of Clinical Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES (United Kingdom)
3. School of Agricultural and Forest Sciences, University of Wales, Bangor LL57 2UW (United Kingdom)

A meta-analysis of existing scientific literature recently suggested that Cd is absorbed more efficiently by sheep if it is in the organic form in grass, than if it is added as an inorganic supplement to the diet. We tested this experimentally by feeding sheep grass from contaminated soil, compared with uncontaminated grass and with Cd added to the diet. To produce contaminated herbage, Cd nitrate was added to soil in 11 lysimeters sown with perennial ryegrass, with a further 11 lysimeters receiving no Cd to produce uncontaminated herbage. In the Cd-treated lysimeters, soil had increased exchangeable K, Mg, and Ca, leachate had increased K, Mg, Ca, Na, and P, grass had increased Cd and reduced Mg, Na, P, Mn, Fe, Cr, Al, and Ni, and there was some reduction in grass yield compared with untreated lysimeters. Grass from Cd-treated or untreated lysimeters was fed to groups of 12 ewes for 2 days, with Cd intake equated by adding Cd nitrate to the concentrate feed of ewes receiving the uncontaminated grass. The apparent absorption of Cd, Zn, Mo, Cr, and Al was increased for ewes receiving Cd-enriched grass, and apparent absorption of Cu was reduced, compared to those receiving supplementary inorganic Cd. Most of the unabsorbed Cd was excreted in feces within 4 days of feeding. The ewes consuming Cd in grass had increased B concentrations in their urine, possibly due to adverse effects of Cd on kidney function. Finally, the ewes were offered a choice of the two herbages and they ate significantly more of the uncontaminated grass. It is concluded that the apparent absorption of Cd and other heavy metals by sheep in a short-term experiment was greater when Cd was in the grass than when the Cd was added in in an inorganic form and that sheep partially avoided herbage with a high Cd concentration.

• OSTI ID: 20698402
• Journal Information: Environmental Research, Journal Name: Environmental Research Journal Issue: 2 Vol. 99; ISSN ENVRAL; ISSN 0013-9351
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ABSORPTION
CADMIUM
DIET
FECES
GRAMINEAE
KIDNEYS
LYSIMETERS
NITRATES
SHEEP
SOILS
URINE