Brown cow really looks like she has an infection in that leg. If you look close at her picture it looks like she has a split in her outer claw which probably where it started. Antibiotics and soak the foot in Epsom salt water if you can.
Are your cows registered? If so what's the number and breed? If not can you take pictures of them and give some insight on what you want to improve on.
I've had cows rip out wires, chew the end of hoses and even try to eat a needle and syringe that I just set down. If they can reach it they will mess with it.