Eikelenboom et al. Murray et al. However, the muscle quality advantages from feed withdrawal are not consistent in the scientific literature. DeSmet et al. In most cases, feed can practically be withdrawn only from the last load.
Earlier loads are usually on full feed until they are shipped.
To better understand feed withdrawal as a standard production practice these benefits and disadvantages were evaluated as a system in a study conducted at North Carolina State University. The barn had 40 pens and the other 4 pens were used to hold the cull pigs and the extreme lightest and heaviest pigs that were excluded from the study. Each pen of 29-32 pigs had pigs of similar minimum and maximum weight with similar variation between pens. Maximum variation within a pen, rather than minimum, allowed the progressive selection of the heaviest third of pigs for slaughter from each pen and simulates the slaughter closeout of a barn where on three occasions the heaviest third of pigs are removed for slaughter. Pigs were presumed homozygous stress negative because they came from lines that had been DNA tested and found negative for the HAL 1843 gene.