Well I am not quite sure what the weather has been doin in your neck of the woods, but here in Texas in Madison county the last month was VERY wet and now it is HOT and DRY, this make for very poor hoof conditions
So if there was a week spot in the hoof in the cow steped on a stone, even a small stone, where the dirt and gotten into the toe will cause the toe to crack, break and this will cause the lameness
What I would recommend, if it is a front foot, get her into a squeeze chute, using a large cotton rope, loop the ankle and lift the foot, using a nipper, trim the affected to to healthy tissue, don't quick her, atleast, this is where you get into trouble, and then using a dremmel tool, get into the area where the crack is gettting close the the hair line, get into it and notch it so you stop the crack from traveling, then treat with tincture of iodine, in the interdigital space, under the toe and where you used the dremmel tool.
If you want to go further, use a Cowslip, on the oposite toe to elevate her off of the affected toe all together, this will take off any weight baring on the damaged toe and allow it to grow out and heal for a few weeks, by then you should have enough health hoof, that she will not have any more trouble.
Good luck
If it is a back foot, it can be done in the same maner, but using a flip table makes life a whole lot easier, and makes it easier for you too, not just the cow
