The animal rights organisation PETA has clashed with Nintendo several times. For example, they didn't like the museum in the latest Animal Crossing game, and they produced a guide for vegans for that very same game. Now they've set their sights on Mario Kart World, and more specifically the character Cow, which as portrayed in the game, has a nose-ring. Nose-rings are generally used to control the animals.
In an open letter to president Shuntaro Furukawa the organisation says this:
"The brass ring in Cow's nose glosses over real-world violence and cruelty to animals. That's why we're asking you to give this beloved bovine a small but meaningful upgrade: Remove the nose ring and let Cow race freely — without any painful reminders of the industries that treat animals like profit-making machines."
The organisation has, as stated, complained to Nintendo on numerous occasions, mainly because their games attracts a much wider audience, including children.
Nintendo has yet to respond, and will likely not do so.