When foot and mouth strikes, all cattle on the infected premises are slaughtered and their carcases burnt, where they were slaughtered. Not only them, but also those within a designated area, which might be infected too. Further, it it wasn't just cattle which were slaughtered in the 2006 outbreak, but also sheep, in the sheep-farming area of the Scottish Borders and for all I know elsewhere.
To my knowledge, old retired ewes living out a peaceful existence as pets of the family, with no contact with any other sheep and never moved from one area to another, were not spared. How could they be? The wind could have blown the infection to them, and the feet of their owners could then spread it around to start it up in another place. When a deadly disease is spreading, you can't leave a pocket of possible infection.
Tuberculosis is another deadly disease.