Why do we have to cleanse and disinfect vehicle wheels, mudguards and wheel arches, when leaving markets but not slaughterhouses?

A. It is a legal requirement to cleanse and disinfect wheels etc. on leaving a market but not on leaving a slaughterhouse. The risk of spreading disease is greater at a market, because vehicles leaving a market may have returned to the loading area after carrying out full cleansing and disinfection and been driven through animal excrement before leaving to go to a farm (or farms). Vehicles leaving a slaughterhouse have either cleansed and disinfected on the premises (which of course will include cleansing and disinfection of wheels, mudguards and wheel arches) or will do so back at base. They are not leaving with live animals to go to another farm. It would be disproportionate to require this measure at slaughterhouses unless there is a significant increase in risk, i.e. during an outbreak of exotic disease such as foot and mouth disease.