The routine inclusion of in-feed antimicrobial growth promoters (AGPs) have long been used to improve performance and to protect against enteric disorders in newly weaned pigs (Hampson, 1994). However, due to increasing concerns about their use in pig production, they are being phased out within the EU. This will put the weaner pig at greater risk to post weaning enteric disorders such as post weaning colibacillosis (PWC), and accentuate the need for alternative, non-pharmaceutical, strategies for disease prevention. These strategies may include the manipulation of dietary protein supply, in order to minimise protein availability to intestinal microflora including enterotoxigenic E. coli (ETEC). The objective of the current experiment was to investigate the effects of dietary protein availability to intestinal microflora through manipulating protein quantity and/or quality on the health and performance of newly weaned pigs in the absence of AGPs when experimentally challenged with ETEC.