There is a wide range in the types of facilities that are used today during each production phase. Housing conditions can clearly influence the pig's performance response, but they will also affect the pig's nutrient needs. For example, pigs that are housed in complete confinement normally have a higher growth rate and feed intake than pigs housed on pasture or drylot. Environmental conditions and facilities can therefore independently and jointly influence the pig's nutritional requirements. Management of a facility that results in a facility environment low in gases, odors, dust, and waste material will help to maintain pig health and result in optimum growth and reproductive performance responses. Such an environment will also be more healthy for the herdspersons working in that facility.