I had never heard of a cow choking on the stuff. We calve in the barn and dad was always johnny on the spot to get that stuff out of the pen. I kinda took the attitude that if the cow wanted to snack on it, let her. Well, I guess not anymore. In fact one of our "straggler" cows calved today, and when I got there she was chowing on the stuff. Pretty hard to get it out of her mouth when she has it clear down her throat! Managed to get it tangled in a pitchfork and she let go of it.
Those are frustrating losses, Soapweed. Totally out of your control unless you are on round the clock patrol.