Effect of withdrawing feed from hogs prior to slaughter on the prevalence of gastrointestinal lacerations at slaughter
To help producers decide whether they should withdraw feed prior to slaughter, we designed a study that examined the effect of feed withdrawal on the proportion of gastrointestinal tract lacerations, prevalence of Salmonella spp. in cecal contents at slaughter, prevalence and severity of gastric ulcers, and meat quality as measured by ultimate pH, color, and water holding capacity. Finally, we analyzed the economic impact of the treatments. This report focuses on the prevalence of lacerations of the gastrointestinal tract found at slaughter. We followed to slaughter, in 3 marketing groups, 900 National Pig Development barrows that we had assigned to treatment. Each marketing group (feed withdrawn once, first group; twice, second group; or three times, third group) had an equal number of pigs that had feed withdrawn for 0 (control) 12, or 24 hours. Overall, 15.7% of gastrointestinal tracts were lacerated in one or more sections including the stomach (8.4%), colon (5.7%), small intestine (2.1 %), and ceca (0.9%). The withdrawal of feed before slaughter decreased the weight of the gastrointestinal tract. The proportion of lacerations in this study (15.5%) is higher than previously reported (4.5%). The difference may be due to the higher rate of evisceration (18 pigs per minute), or our more detailed examination of the gastrointestinal tracts.