Liquid feeding of growing pigs is believed to increase feed intake and growth performance compared to a dry diet. There is little information on the comparative feed conversion efficiency of pigs on the two forms of diet or the underlying physiological basis for the differences and how liquid diets affect the absorptive mucosa of the small intestine. This study was designed to investigate differences in feed utilisation and mucosal structure in modern genotype pigs offered equal amounts of feed in dry and liquid form. Additionally, the effect of reducing the pH of the liquid diet was considered.