I don’t like the question. It should read ‘which country spends most on its companion animals?’. Having got that out of the way the answer is obvious from bar graph on the right below:

Research from the market research company Gfk published on The Economist tells us that, unsurprisingly, America is the country where they spend the most on companion animals. American has by far the biggest companion animal market on the planet. The bar graph on the right shows the companion animal spend on care per person for 2019 in US dollars. I am going to presume that the guys who created the bar graph worked out how much Americans spent as a whole on companion animals in 2019 in terms if ‘pet care’ (whatever that means) and divided the number by the population of the USA. The figure they arrived at is about US$160. This sounds low but if I am correct it is an average for every American in the USA and of course millions of people don’t have a companion animal which pulls the number down.

Also unsurprisingly, China, came somewhere near the bottom of the list at around US$5 per person. I’ll say it for the tenth time: China does not have animal welfare laws and they are the world hub for cat and dog meat and the supply of fur from cats and dogs. Millions of animals are killed in an unegulated way in these businesses annually. I had to get that out of the way too. Perhaps the Covid-19 pandemic which is believed to have started in China might encourage the government of China to introduce some animal welfare laws? Please. I am begging.
Britain, being a land of animal lovers (supposedly), comes second at about US$90 per person. The ‘pet care market has grown by 66% over the past ten years. Sixty-six percent of Americans are guardians to companion animals.
SOME MORE ON PET FOOD MANUFACTURERS:
Please search using the search box at the top of the site. You are bound to find what you are looking for.