Question:  query regarding a cow showing the signs of lameness in one front leg & ulceration on the coronet region, probably  infecting  the tarsal bone 
Answer:  wash the region with potash solution , apply dressol spray on the affected area for 3 times in a day , inject prednisolone   & enrofloxacin  as directed for 3 days [one shot of   melonex plus  i/ m ly -- if required ]