Do hope you find your missing cow. Now winter is approaching, farmers will be bringing cattle in, moving fields, feeding etc. and if theiy have an extra cow, hopefully they will make enquiries, advertise, whatever, to try and find the rightful owner. I know where we are, with it being open moorland, quite often cows, and sheep, get in with other herds and flocks, and are not noticed maybe for weeks. So don't give up hope.