1. AOAC, 1990. Official Methods of Analysis, 15th Edition. Association of Official Analytical Chemists, Washington, DC.
2. Boggs, D.L., Merkel, R.A., Doumit, M.E., 1998. Livestock and Carcasses, 5th Edition. Kendall Hunt Publ. Co., Dubuque, IA.
3. Briggs, M.H., Pitchford, A.G., Staniford, M., Barker, M.M. Taylor, D., 1970. Metabolic effects of steroid contraceptives. In: Briggs, M.H. (Ed.), Advances in Steroid Biochemistry and Pharmacology, Vol. 2. Academic Press, London, p. 112.
4. Chesters, J.K., 1997. Zinc. In: O’Dell, B.S., Sunde, R.A. (Eds.), Handbook of Nutritionally Essential Mineral Elements. Marcel Dekker, New York, p. 185.
5. Feed intake, rectal temperature and serum mineral concentrations of feedlot cattle fed zinc oxide or zinc methionine and challenged with infectious bovine rhinotracheitis virus;Chirase;J. Anim. Sci.,1991