Taming a equus is a passive tame not a knock out. You'll need to make a trap so it won't run off and get killed. You'll need as much berries as the DeX says. And have a ghillie suit to not spook it.But in case you accidently mount off and lose some taming effect have some more berries with you just in case. This is how I did it.
I would usually find some in survival evolved. Over by the green obelisk by the swamp part of it. There would usually be 3. Bring something to protect you because I just picked it up with a argent and take it some where safe. The next spot is by the redwoods but by the volcano fly to the other mountain where you'll see wet ground that looks black and there will be brontosaurus and there will be 3 but beware of raptors, carnos. And rexes.
Well the Equus is a hard tame,even a t-rex is easier but you will need around 30-60 carrots so to get that you will have to plant some get a medium plant crop and in order to the seeds go to the nearest forest and keep gathering plants until you get the seeds plant the seeds with fertilizer inside the plant crops.
This creature is a pain to tame but worth it. When I first got it I was like “Now, what in the world am I going to do with this?” Then I realized, it is great for knocking out wild Dino’s if you are short on tranq arrows (knocked out a lvl 120 sarco with 3 back kicks). It is also good for a mobile narcotic maker. Just put some rotten meat in this bad boy and run around getting narcoberries and use it’s saddle to make all the narcotics you want. Bam!!! Then you got all the taming supplies you need to go get some other Dino’s.