The United States and China are the dominant producers and consumers of meat. And even between these two countries, apples to apples comparisons are not helpful as production practices are not the same.
the differences are too many to put succinctly, they're (IMO) way behind in standards on every level as a result of exponential growth in meat consumption that is practically unprecedented. I'd start here: https://sci-hub.se/10.1126/sciadv.aar8534
