Effects of Facility Design on the Stress Response of Market Weight Pigs during Loading and Unloading

  • Anna K. Johnson (Iowa State University)
  • Larry J. Sadler (Iowa State University)
  • Jill R. Garvey (Iowa State University)
  • Tony J. Uhlenkamp (Iowa State University)
  • Michael Faga (Iowa Select Farms)
  • Corky Feuerbach (Iowa Select Farms)
  • Howard Hill (Iowa Select Farms)
  • Ryan Bailey (JBS-Swift & Company)
  • Matthew J. Ritter (Elanco Animal Health)


The objective of this study was to determine the effects of finisher pig facility design on pig stress responses at the time of loading for the market weight pig. The new (NEW) design had 192 pigs / pen with internal swing gates that were used to manually pre-sort market weight pigs on the day before loading. Traditional (TRAD) design had 32 pigs / pen; it was not feasible to pre-sort market weight pigs prior to loading. During loading, treatments were alternatively assigned to trailer decks. Pigs were loaded onto straight deck trailers, provided with ~0.41 m 2 / pig and were transported ~1 h to a commercial plant. During loading and unloading, the number of pigs displaying open mouth breathing (OMB), skin discoloration (SD) and muscle tremors (MT) were recorded. At the plant, dead and nonambulatory pigs were recorded during unloading, and nonambulatory pigs were classified as fatigued (stress-related) or injured. Total losses were defined as the sum of dead + non-ambulatory pigs at the plant. Data were analyzed by Proc Glimmix of SAS. NEW pigs had lower (P ≤ 0.05) percentages of OMB, SD and MT during loading and unloading compared to TRAD pigs. NEW pigs had fewer (P < 0.05) dead pigs (0.01 vs. 0.23 ± 0.05 %), total nonambulatory pigs (0.29 vs. 0.66 ± 0.12 %) and total losses (0.30 vs. 0.89 ± 0.14 %) at the plant compared to TRAD pigs. In summary, utilizing large pens and pre-sorting prior to loading, reduced physical signs of stress during loading and unloading, and reduced total losses at the plant by 66 % compared to pigs from traditional pens.

Keywords: ASL R2469

How to Cite:

Johnson, A. K., Sadler, L. J., Garvey, J. R., Uhlenkamp, T. J., Faga, M., Feuerbach, C., Hill, H., Bailey, R. & Ritter, M. J., (2009) “Effects of Facility Design on the Stress Response of Market Weight Pigs during Loading and Unloading”, Iowa State University Animal Industry Report 6(1). doi: https://doi.org/10.31274/ans_air-180814-881

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Published on
01 Jan 2009
Peer Reviewed