[Tagging] What key for animal related "amenities"?

[Martin Vonwald]

Hi!

I'm looking for a better key than amenity for any animal related
feature. For example I want to tag a horse walker [1]. I could use
amenity=horse_walker but this key is already flooded with pretty
everything. Any ideas for a better key?

Thanks.
regards,
Martin

[1] http://www.topnotchequestrian.com/bilder/horse_walker_illustration1.jpg