Here is a formula I found for deer (from butcher website):
Live weight x 0.78 = field dressed weight
field dressed x 0.75 = hanging weight
hanging weight x 0.75 = edible meat
From research paper out of North Dakota:
Jensen, Bill. 2000. Estimating big game weights — a crash course for
the curious. North Dakota Outdoors 63(3):26-27. Jamestown, ND:
Northern Prairie Wildlife Research Center Online.
http://www.npwrc.usgs.gov/resource/mammals/bgame/index.htm
(Version 11APR2001).
Over the past 40 years retired big game biologists Jim McKenzie and Jack Samuelson, as well as big game supervisor Roger Johnson and other North Dakota Game and Fish Department biologists, have collected weights and measurements on the six big game species found in North Dakota. By using the equations found in Table 1, and knowing the dressed weight — whole body or live weight minus internal organs — it is possible to derive a good estimate of an animal's live weight.
Bighorn Sheep
......Ram (dressed weight x 1.13) + 31.9
Elk
......Cow (dressed weight x 1.07) + 110.4
......Bull (dressed weight x 1.30) + 24.4
Moose
......Cow (dressed weight x 1.33) + 61.0
......Bull (dressed weight x 1.27) + 78.2
Mule Deer
.......Doe (dressed weight x 1.28) + 3.6
.......Buck (dressed weight x 1.20) + 9.9
White-tailed Deer
.......Doe (dressed weight x 1.30) + 1.60
.......Buck (dressed weight x 1.15) + 11.7
Pronghorn
.......Doe (dressed weight x 0.95) + 38.7
.......Buck (dressed weight x 1.17) + 16.7