On-Farm and Pre-Slaughter Management Approaches to Reducing Stress Response and Improving Pork Quality in Pigs

108 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2002.Experiments were conducted to evaluate the effects of on-farm and pre-slaughter management factors on stress response and pork quality in finishing pigs. The first study evaluated the influence of farm of origin and slaughter plant on pork quality and demonstrated that each had major effects. In addition, there were significant (P < 0.05) farm x processing plant interactions for most of the important pork quality traits. Studies investigating the effects time of feeding magnesium (Mg) fortified diets prior to slaughter showed that feeding Mg sulfate for a period of 5 or 2 d prior to slaughter may be beneficial in improving (P < 0.05) drip loss compared to controls and pigs supplemented with Mg sulfate for 3 d. Another study investigated the effects of level (1.6 vs 3.2 g/pig/d), source (sulfate vs proprionate vs proteinate), and time of feeding (5 vs 3 vs 2 d) of Mg on pork quality. Results from this study indicate that sulfate produced the most improvement in meat quality traits and that the lowest level (1.6 g) and the shortest feeding period (1 d) may be effective in improving color and water-holding capacity. For the next round of studies, an animal handling model was developed to simulate the stress incurred from pre-slaughter handling. The handling model was first used in a study that investigated the effects of Mg and handling intensity on blood acid-base balance and demonstrated that pigs subjected to a high intensity handling model were subject to a metabolic acidosis condition that was characterized by a low blood pH and base-excess with high lactate production. Mg lowered (P < 0.05) blood lactate but was not able to prevent the metabolic acidosis in the high intensity handled pigs. The final study investigated the effects of dietary electrolyte balance (DEB) on blood acid-base parameters in pigs subjected to a high intensity handling model. Levels of TCO2, pH, HCO3-, and base-excess in the blood increased linearly (P &le; 0.05) as the level of DEB increased. In conclusion, results from these studies show that animal handling, feeding supplementary Mg, and altering the DEB of the diet may be utilized to reduce handling stress and improve pork quality in pigs. However, further research with these strategies under commercial conditions is warranted before recommendations can be made.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD