I had a heifer show up lame a few weeks ago. I knew she was getting close to calving. She ended up with what the vet calls hip lock and was dragging her right rear leg. Had to drag her out of a pond that she managed to get into. Unfortunately, I found the calf and the coyotes beat me to it. I have a feeling she couldn't get up to defend it. got her penned up and some anti-inflammatory from the vet and she is up and fine now.