Two Year Old Cow with scours

I have a two year old cow - been bred once - who has developed the scours. She has been eating coastal grass and recently I began to feed her and the young bull calf who pasture together 20% cubes. She is a black angus. I have never experienced this before. Is there anyone here who can give some insight? She is not easy to handle, so it may require me loading her up and taking her to the vet. I also noticed ticks in her ears. The young bull is fine.

Perhaps the cubes were to rich to start her on -

Thanks,
Melissa