I just got a call from a Rancher wrt helping with coyotes attacking and killing his calves. It just started happening and he's lost 2 so far. Initially he told me that the damage was around the anus so I was thinking that it was ravens. After seeing the picture, I highly doubt that ravens would do that.
Does this look like the work of a coyote? Maybe couldn't finish the job before the Mother cow ran him off. There are also wolves and bears in that area and the bottom of the wound looks a little like bear claw marks to me.
I'm going to head up there and have a look.