They mean the manure (poop) from the cattle. Before the days when you could buy redworms over the Internet, the place to find them would be in or under manure in a field.

fresh manure of any kind should be used in a worm bin sparingly, as it may heat up to much as it starts decomposing microbially

also it's not adviseable to use any meat material or any fats in vermicomposting, and in bin composting only if you have a good hot process going

Bill