The first step to good and productive farming and good husbandry is to do some tests. Test your soil. What kind of soil do you have? Light soil with lots of sand, heavy clay soil, or something in between? What about the ph of the soil, minerals ect. What klimat zone are you in? Do you have long dry spells or do you have long rain periods? Is it windy? How much shade? You can find diffent soil test kids in the feed or suply stores. Sometimes you can get a free test from companies that sell fertilisers. Or you look at the weeds that are around. Some weeds are very good
soil indicators.
The goal is to finde the animal or breed that is comfortable with the environment and raise your awareness to potential problems in that environment. You have horses so you know already many things they don't like. A horse does not want to stand on muddy soil all day, they have problems with too fat grass, long rain periods and drafty barns. You know how to fight a horse fly infestation and prevent worms.
Every animal has things they don't like, should not eat and a flies/ worms that can cause illnesses.
If you live on a windy, cold and wet corner with soil that produces more heather than grass, you may have problems to raise happy, healthy cows but highland cattle may do great and skudden sheeps would love it.
Don't worry, your land may be woodland that is dotted with little spings or a dry grass patch on a plateau there is a livestock breed that will love exactly what you have.
It is always better to have a good adapted breed that may produce a little less, than a potential high productive breed that that has all you want but that gets sick the moment it leaves the stable.