Don,
I'm sorry to hear about the cow and calf. I hope the cow is OK. We've lost one calf this year and had another injured, both by cayotes. They seem bigger this year, more aggressive and there seems to be more of them. They run the new born calves and force them to stop, start and turn quickly until their undeveloped legs and joints give out and then .....
I know you shouldn't get too attached to your animals but you can't help it, can you? The only way I've been able to handle it all these years is to think of it as natural selection at work, part of a bigger plan. I know that's not much comfort but the rational behind it is the crutch that's got me by.
Let us know how she's doing.