It can be genetic or from too much grain. If you don't know the genetic history of the animals in question, I would assume genetic, if it is on either both front feet or both back feet. One foot growing out can be caused by an injury at any time in the animals life.
You can have the feet trimmed to allow the cow to continue producing income(calves sold to feedlots) but daughters should not be retained from any animal with poor feet, whether sire or dam.
If the cause can be traced to over feeding, or an injury, offspring can be kept without worry.
Jason Trowbridge Southern Angus Farms Alberta Canada