I was wondering in case of SHTF and you have horses and other animals ( other than cows and goats ) will you think of drinking their milk ?

I am illiterate in ths field, so does a mare produce as much milk as a goat for example ?? Looking at their sizes, it is logical that the volume of mare's milk will be greater than that of a goat. But I never heard of anyone doing that in an emergency. But then agian, I never heard of anyone skinning a snake and using the skin as a water canteen before seeing Dave Canterbury do it in Dual Survival.