|Powell, J Mark|
Submitted to: Sustainable Land Application Conference
Publication Type: Proceedings
Publication Acceptance Date: 10/15/2003
Publication Date: 1/4/2004
Citation: Li, Y., Mccrory, D., Powell, J.M., Saam, H., Jackson-Smith, D. 2004. Heavy metal concentration in manure on wisconsin dairy farms. In: Sustainable Land Application Conference, January 4-8, 2004, Buena Vista, Florida. p.111. Interpretive Summary:
Technical Abstract: Excessive heavy metal concentrations jeopardize the good functioning of soils and may contaminate crops and pose health risks to both livestock and humans. Wisconsin has the largest numbers of dairy operations in the US, with the majority producing most of their own feed, and recycling manure through their cropland. Little information is available on the heavy metal concentration of dairy manure. Manure and feed samples for lactating dairy cows and heifers were collected from 52 randomly selected Wisconsin dairy farms and analyzed for heavy metal contents. Mean concentrations of Cu, Pb, Cr, Cd and As in manure of lactating cows were 52.2, 1.4, 11.2, 0.2 and 0.3 mg/kg dry matter (DM) and in the manure of heifers 43.1, 1.7, 11.0, 0.2 and 0.5 mg/kg DM, respectively. No significant difference in any heavy metal concentration in manure of cows or heifers was detected. However, levels of Zn and Ni (184.2 and 10.1 mg/kg DM, respectively) in lactating cow's manure was significantly (p <0.05) higher than concentrations of Zn and Ni (126.6 and 7.6 mg/kg M, respectively) in heifer's manure. The heavy metal concentrations in these manures were much lower than USEPA regulations. In general, levels of Cu, Cr, Ni and As reported in this study are higher than levels reported in the limited literature available for this subject. Further analysis of feeds will be used to identify relationships between heavy metal intake and excretion by dairy lactating cows and heifers.