In my experience, it is relatively plausible that the animals are sold in a single location, that far away. Granted, this is absolutely anecdata, but it does prove a point.
My experience: For decades, my father, my grandfather, and my great grandfather sold cattle via the Chicago markets. This is a trip of around 1000 km. This also originally started when our part of the US would have been no different than a very backwater part of a developing nation. No roads, no rail, no infrastructure, really, until you got to within 400-500 km of Chicago from where we live. And yet, they moved cattle that far to one single marketplace.