Beef cows are accumulators. And their feed often contains plastics.

Just thought it was interesting considering they are 'grass-fed'. Is that just a lie? Or maybe it's something else, like if they're drinking water from plastic containers that sit in the sun all day

You're probably imagining the marketing depiction of "grass fed"

https://www.primalmeats.co.uk/wp-content/uploads/2016/12/gra...

But nobody said it was coming straight off the ground!

https://thumbs.dreamstime.com/b/cows-eating-trough-made-blue...

https://c8.alamy.com/comp/2CFFY4J/hay-bales-wrapped-in-heavy...

It's a good point. I'm not an ag lawyer, but I am willing to bet that there's wiggle room in any grass-fed definition set by the USDA.

And you're right, there's also: plastic from water sources, plastic in the field that gets taken up by the gras, supplements given to the cow, plastic in the cutting board the meat was cut in, plastic the meat was wrapped in . . . it's hard to get plastic out of your supply chain.

Even here in Switzerland grass fed means that like 70% of the year they eat grass from their fields, conserved in large plastic "rolls"