I’ve only been on half a dozen, I’m certainly not a regular. But typically any hard surface where cows move through is covered in @*!# afterwards. Indoor winter areas routinely have scrappers pulling @*!# along the floor, they never look spotless after a sweep. If you wanted to get into the safety, which is what the original scare post is angling at, you could throw in BSE and CJD or foot and mouth. Take it a step further into the abattoirs and you could have a look at the excrement that ends up on slaughtered carcasses and the ecoli outbreaks that causes.
I’m not anti-farmer or anti-meat, but there’s no farm with livestock I’ve been on that was a clean as a lab, and people happily eat the products, myself included. If I dropped half my sandwich on the floor in a lab and the other half in a cowshed in winter, I know which one I’d prefer to finish.