When searching for horse sounds (Звуки коня), you will generally find the following categories:
Rhythmic sound effects of hooves hitting various surfaces (grass, pavement, or dirt).
Typically ranges from 100 KB to 5 MB depending on the length and quality of the clip.
The sound of a horse munching on hay or grass. Common Sources for Download
Most downloads are provided in MP3 (for general use) or WAV (for high-quality editing).
Community-driven sites like Freesound.org offer a wide variety of recordings under Creative Commons licenses.