1. This document is AN124, one of a series of the Animal Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date September 17, 2001. Revised April, 2004. Revised December 2009. Visit the EDIS Web Site at http://edis.ifas.ufl.edu. 2. Robert Myer, professor; Travis Maddock, post-doctoral associate; D...