Distressed Cow Sounds

Well, tonight I was doing my cow checking thing as usual. When I walked out to check the heifers I heard a cow bellaring VERY loudly. It kind of scared me because I thought maybe a cow had gotten into the yard and was planning on attacking me, kung fu cow style. Okay, I realize I was being irrational, but I tend to get a little more irrational at one in the morning, in the dark. So I decided to just finish checking the heifers then try and figure out where the distressed cow was. There weren't any calves and the heifers weren't even trying to think about calving. They were all calmly munching hay. So that's good. Then I tried to listen and see where the sound of the cow was coming from. I couldn’t tell exactly, but all of the cows are in large pen behind the house. I decided to check them, in the safety of my vehicle. Ya know, just in case. I drove around the pen and found all of the cows calmly munching hay, just like the heifers. I rolled down my window to listen for the cow and could barely hear her, so I figured I was moving farther away. I then went back into the yard and listened a little more. The cow was being equally dramatic as before, and she sounded close, but I knew it wasn't one of ours at least. The weird part is the neighbors on the west side of the property line don't have cows anymore. All I can guess is that another neighbor had a renegade cow who jumped a few fences. She probably got lost and couldn't find her herd, hence the distressed cow sounds I was hearing. I just went out again a few minutes ago to check again, and she's quieted down a bit. This is a problem I'm leaving until morning. You know, when it's light out.