4Fisher G E. 1991.Eect of cobalt defciency in the pregnant ewe on reproductive performance and lamb viability [J].Research in Veterinary Science, 50: 319-327.
5Lopez-Guisa J M, Satter L D. 1992.Effect of copper and cobalt addition on digestion and growth in heifers fed diets containing alfalfa silage or corn crop residues [J].J Dairy Sci, 75:247-256.
6Oung R. 1979.Cobalt in biology and biochemistry [ M ].London:Academic Press.
7Paterson J E,Macpherson A.1990.The influence of a low cobaltintak on the neutrophil function and severity of ostertagia infection in cattle [J].Br Vet J, 146:519-530.
8National Research Council. 1980. Mineral Tolerance of Domestic Animals [M].Washington,D.C.:Dational AcademyPress.
9Gawthorne J M, Waston J, Stokstad E L.1971.Automated methymalonic acid assay [J].Anal Biochem, 42:555-559.
10Geogierstill.et al. Mineral nutrition of animals. Moncellous Bookbinders Ltd. London, 1982:186 - 192