Anime horse girls: they’re in. The Steam debut of Umamusume: Pretty Derby, a gacha racing and management sim where you train horse girls inspired by real racehorses, has brought a Japanese juggernaut to PC and a global audience. It has also indirectly convinced a whole lot of those players to spend their would-be gacha funds on a much nobler cause: feeding real horses.

The current adopted daughter of the Umamusume community is Haru Urara, a pink-haired underdog who shares both name and history with a horse who famously lost every single race of her competitive career. Haru Urara, the real, 29-year-old horse – and 29 is pretty old for a horse, especially a racehorse – has exploded in popularity in her retirement thanks to her digital counterpart, with Umamusume fans heaping praise and fan art on the character.

Twitter user ChrisValence has helpfully collected that fan art, collating the “We love our girlfailure daughter, 1 billion kg of ryegrass to Haru Urara” movement.

All that fan art is also furthering the campaign to heap grass on the real horse.

A few days ago, a viral Twitter post from user Tarumage noted that, “to support Haru Urara, you can send a gift of fresh ryegrass through a special delivery service. This refrigerated, highly palatable ryegrass (not hay) costs 6,000 JP yen, including shipping.” That post has 14 million views at the time of writing, demonstrating the throngs of Haru fans that turned up.

That service, machine translated as the Fresh Hay Bank, is described as a crowd-gifting site that lets users deliver delicious and healthy feed to retired horses. One 5 kilogram box, which costs about $40 USD, is said to be good for two horse-sized meals.

At the time of writing, 2,590 kilograms of grass has been donated to Haru Urara, though only some of that was sent in the past few days. That said, 35 kilograms have been donated in the past few hours alone. I’ve reached out to the company for specifics, and for comment on this spike in donations.

After that Twitter post first went viral, many Umamusume fans, and eventually Tarumage themselves, noted that the donation portal for the website had crashed. Sure enough, when I checked it earlier today, it had once again buckled due to high traffic. An English error message reads: “It’s very crowded right now. Please wait a while and try accessing again.”

Umamusume has so effectively galvanized the horse girl fan base that it has dedicated “guidelines for visiting stables in Japan” on its website, encouraging players to be respectful and avoid repeats of past incidents of “visitors neglecting stable rules, trespassing, and photographing/filming without the stable’s consent.”

I recently visited Japan for the first time and I’ve been around horses several times here in the American South, so I speak with some experience when I say that you don’t want to mess with horses, Japanese rules, or especially Japanese rules about horses.

I walked an hour in the rain to play horse girl gacha game Umamusume: Pretty Derby at the actual Kentucky Derby.