Glenn, your question almost needs a minimum of a pamphlet
answer, here is a hopefully a short read and should not be considered anywhere near complete
Idyllically the soil would be able to support every animal you keep on your homestead, put simply the more animals you have the more resources (Money, Time and Labor) that are required,
There are only 8760 hrs give or take per year how do you want to use them
Example; TIME and cost of FEEDING a cow being fed 3lbs of corn (you do want some fat in your meat, as very lean ground meat will not hold together, COST) requires one motion of dipping, say a 3lb
coffee can into a storage bin 3 seconds each time, if you are feeding two times a day per cow 6 sec/day/animal approximately 36 min/year, call it 10 sec per feeding and you are up to 2 hrs/yr/animal, doesnt sound like much but it all adds up, the more animals you keep the more time required,
Oops i forgot about
HAY, initial COST and a lot of TIME (ever try to moving/stacking bales of hay? squares are relatively easy depending on weight, now try a 800/1000/1200 lb round bale, which are either 4/5/6 ft in diameter, yes they weigh that much), how good of health are you in, do you have access to a
tractor (initial COST and fuel COST) Doing it by hand requires power, brain as well as muscle, Brain power for the planning and execution of getting the bale(s) moved to your storage facility and then again to the feed area, you will likely need an extra hand to help (COST), i am 6'3" in the 230lb range there were times, especially in the beginning that were quite taxing (no tractor!!) Grass doesnt usually grow year round especially the farther north you are located, and you will need hay to supplement the grass, now there is a storage of the hay to consider, true you only have to build it once (initial COST) but it still needs to be built, how many animals depends on how large, Note this is just feeding one specific animal, other animals may/will require other supplemental feed and housing
Dont forget the COST of fencing, free range is a nice idea until your errant animal gets into a your garden, worse what if it is your neighbors garden (talk about COST)!! ever try to control a 1 year old bull (approx 900lbs that gets a hey i am feeling frisky attitude) and bolts on you,
Housing initial COST, for birthing (want
milk?) cows dont just give off milk, like humans they have to bear offspring to lactate and that usually requires a vet (COST) unless you are doing it yourself), feeding station(s) {dont want the feed to go to waste or become contaminated}, watering (pumped? COST {piping valves and other sundries initial COST} or done by hand? MAJOR TIME, a cow will consume 5 gal of water at a time, i use bathtubs or deep sinks for my watering stations, Think they dont need housing, think predators
Manures, (did he really have to go there) nope, but i did, a resultant of the aforementioned COST(s) and there is a lot of info out there on what you can do with it, but remember you still have to do something with it and the more animals you have the more you have to deal with
Homesteading requires lots of time, especially if everything is done by hand, either that or more people needed to accomplish the work, which means more food that needs to be produced to feed the "help", IMHO the more automation the better, there is a reason they call them chores, less chores leaves more time to enjoy your family, friends and homestead
Hope this helps clarify the subject
regards Stark