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.
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.