I had loads last winter in my ponies field. They didn’t eat it and it kept the lower part of it that would otherwise have looked bare green looking.
I did get a bit worried as it seemed to be taking over the grass completely.
This year it’s gone. I’d forgotten about it really until reading this.
MR P possibly sprayed it
Edited to say I just checked and no he hasn’t done anything so it’s just dissapeared this year