I found this post on this web and a person recommended a mod called Twoftmama No Wildlife (Game Performance Register Animal Control help - nraas), But I don't know if I want to use it together with nraas register, how do I adjust the settings of Sims 3.

And My game often freezes because of too many animals in the world, but after I lower the number of Register's wild animals, there are still many animals like horses that will appear in the game again. Why?

If you can solve my problem, I will be very grateful.

Twoftmama's is a tuning mod that basically just makes those settings the default, while Register can edit tuning per-save. If you find it does the job, it's just fine to use both.

The issue with managing strays completely, as mentioned in the post you linked, may still be present.
Could you confirm if you are actually seeing wild horses in the world with Wild Horses set to 0 in Animal Control? It doesn't affect horses who have been adopted into households.
You can adjust whether horses are allowed to move into town both in EA and NRAAS Story Progression, and you may need to remove preexisting ones from their homes.