RE: Live weight to dressed weight???
There really is no reliable chart or formula that will give you dressed weight by measuring chest girth. On the chart pocomoke gave, I think the live to dressed weight ratio is fairly close. However, it doesn't take into account the length of the animal. Weighing the dressed animal on a certified scale is the only accurate measure. I tried all of the charts last year after doubting my deer's dressed weight, and came up with answers ranging from 140-240 pounds!
A reliable scale is the only way to know for sure. Around here, weight determines how big a deer is, so most everyone weighs them.