Although the water intake estimates for the different classes of pigs varies substantially, some general recommendations can be made. Estimates for different weight classes of pigs are given in the table below. To compete in today's global markets the USA pork industry is rapidly changing from treating pork as a commodity product to one focused on functional and conformance quality. In most cases, they withdraw feed from the last load but earlier loads are usually on full feed until they are shipped. The benefits of feed withdrawal are not without risks including a possible rise in the proportion of pigs with gastric ulcers or an increase in the proportion of pigs excreting Salmonella spp.
Pork is a major cause of foodborne salmonellosis throughout the world.
In Denmark in 1993, pork was the most important source of foodborne salmonellosis when meat contaminated with S.infantis accounted for an outbreak of 20 cases per 100,000 inhabitants. The handling and transport of pigs to slaughter has long been recognized as increasing the prevalence of Salmonella spp. To counteract these inherent risks researchers have been investigating techniques that may decrease the risk of contaminating the carcasses. Withholding feed from pigs before slaughter decreases gastrointestinal contents and appears to decrease the risk of gastrointestinal spillage and consequent carcass contamination. However, feed withdrawal is stressful and may increase the proportion of pigs excreting Salmonella spp.