Animal medical devices are also medical devices, and they need to be registered and regulated by the MDD or MDR regulations, just like regular human medical devices. And most of the manufacturers are doing medical devices for human beings, so it's easy to follow this way of thinking. But the animal device market is less willing to do this than the human market, which requires a specialized investment in manpower and resources.
Animal medical devices are not subject to any regulation. Any medical device, as long as the label says it's for animals, and the model number has a Vet on it, you can just sell it, and someone will pay for it. Animal medical devices are not regulated by medical device regulations, either in the EU, US, or China. The regulatory threshold is much lower.