"I see a big tree and a big horse."

Translation: Vidím velký strom a velkého koně.

[crazykidcraig94]

Why would it be velkeho instead of velky? Is is because the horse is an animate object whereas the tree is an inanimate object?

[tragram]

You are correct, the difference between the two is that one of them is animate and the other one inanimate. :)

[Ale632702]

Why not "Vidím velký stromy a velkého koně"?

[VladaFu]

Sorry, disregard the previous. It is one tree. It must be velký strom, stromy is plural.

[venik212]

I find it interesting to discover that trees (and I assume that also grass, flowers, etc.) are considered inanimate from the perspective of Czech grammer. Biologists would strongly disagree ;-)