I suspect it's more likely derived from the breed of cow - Holstein Friesian - Wikipedia. There's a farm location and the girls can end up getting milked copiously (possibly even more than an actual cow).
FunFact: when i first played this back in 2021, it was actually spelled Holstain with an A. in fact, if you hold an old Nokia phone up to the screen and read through the camera app the spelling changes back to Holstain
