Q. My mare has milk bt found stuff that looks like a steak would look like she was about months along no foal though
A. It sounds like your mare may have foaled but lost the baby. You likely found the placenta. It's possible the baby was born and preyed on by something. Keep looking around, you may still find it. Inspect the steak like substance. If it is placenta you want to make sure it looks intact and not ripped though it may be hard to tell if a predator has moved it around. Watch your mare carefully for signs of illness as she may have retained some or this could be a miscarriage. It's inclear how far along she was.
A vet check would be a good idea just to ensure her uterus is not injured or infected and she is otherwise in good health.
I'm sorry. It's difficult when these things happen and you aren't sure exactly what or why.