energy is really a poor way to determine if a caliber is suitable for an animal.

I hunt deer most often, and have been fortunate enough to take them with a variety of calibers. Therefore, I' ll write about them because I feel that I know what I' m talking about

You kill a deer with damage, not energy. Therefore, the wider and/or deeper your wound canal is, the better.

A 223 has much more energy than a 357, yet the 357 will kill a deer faster (when fired from a rifle or pistol) at 50 yds. than a 223 b/c it will create a larger wound channel...more of what keeps the critter alive gets destroyed (organs) or lost (blood)

if you are looking for calibers that are very effective on deer, despite low energy, look at the:
(pistol or rifle)- 357mag, 44 spcl, 45 Colt, all with a heavy soft point or hard cast bullet

these calibers do a tremendous amount of damage out to 60 yds when fired from a pistol, and about 100 when fired from a rifle, with reletavely low energy