Riding the Dilu Horse — ruling 1

The spell’s effect has no duration. The targeted creature gets +2/+2 until the game ends or it leaves the battlefield. It has horsemanship until the game ends, it leaves the battlefield, or some other effect causes it to lose horsemanship.

Riding the Dilu Horse : règles, fonctionnement et interactions (MTG)

Riding the Dilu Horse is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Target creature gets +2/+2 and gains horsemanship. (It can't be blocked except by creatures with horsemanship. This effect lasts indefinitely.)

How it works : Riding the Dilu Horse

Original English text — Wizards of the Coast / Scryfall

#1October 1, 2009· Wizards of the Coast
The spell’s effect has no duration. The targeted creature gets +2/+2 until the game ends or it leaves the battlefield. It has horsemanship until the game ends, it leaves the battlefield, or some other effect causes it to lose horsemanship.
No other card is named in this ruling.