Old Sweat said:
There probably is a time and place for pack animals. I found the following data on animal loads on p. 134 of The Field Service Pocket Book 1914 reprinted with Amendments 1916:
Pack-animals - Load (pounds)
Mules and ponies 160 lb.
Pack-horses 200 lb.
Camels 320 to 400 lb.
Bullocks 200 lb.
Men 50 lb.
Donkeys 100 lb.
Don't forget that in some circumstances food and perhaps water for the animals would have to be carried. If anyone is interested in more data, pm me.
I led a platoon from 1PARA on a 'Hearts and Minds' trip through the Jebel Akhdar mountains in northern Oman back in the 80s. We had a 'donkey walloper' section attached from the Jebel Regiment, with four donkeys and about 6 handlers I believe. The donkeys carried water and some rations for us, and some firewood for the JR troops (their rations were mainly homemade chapattis cooked over a juniper fire and they also ate at local villages).
It was pretty tough slogging, as described in this article
"The Jebel Akhdar is an elevated plateau measuring about
twelve miles from north to south and eighteen miles from
east to west. Its average elevation is 6500 feet and it is
locked behind sheer cliffs of rock and shale, some rising
10,000 feet above the surrounding plain."
http://www.globalsecurity.org/military/library/report/1985/MJB.htm
Although we were glad to have them along, the donkeys were a constant pain in the Ass (forgive the pun), seemed quite hard to manage, and were very noisy at times. I also seem to remember that the Omanis insisted that the 'beasts of burden' not be loaded with more than 60-70lbs each, while we soldiers carried more than that.
Regardless, the animals and their handlers were tough as nails and impressed us with their powers of physical endurance and effortless mobility in very rough terrain, at altitiude, and in very hot weather. We certainly wouldn't have been able to stay out for as long as we did without them.