Dehydrated ground beef will last how long?

I don't know how long…I have a bunch in the freezer waiting to mail.

Based on your dehydration time/temp it is probably very dry; the dessicant may not do any good.
Oxygen will cause …oxidation, especially of the fats that remain in the meat. Remove the oxygen either by vacuum sealing or using an oxygen absorber- same technology as chemical hand warmers- iron compounds bind oxygen. (Not the same as a dessicant)
Freezing until you leave on the trip will slow spoilage down to almost nothing.

Thanks for the insight, Jim.

I don't know how long it will last but I do know someone that tried it. The problem he had with it is that it is not easy to rehydrate it. The Fat acts like a waterproofing material. Water has a hard time getting in to rehydrate it.

If you started out with very lean meat and removed most of it after cooking it might work. You will have to rehydrate some to see how well you did. Most people I know just bring kerky or dry salami to satisfy the need for beef. Other lean meats such as chicken or turkey would probably work better.

Here is a good link about dehydrating ground meat so that it will rehydrate better.

http://www.backpackingchef.com/dehydrating-meat.html