Skip to main content
Unpublished Paper
Behavioral Associations during a Human Approach Test and Performance of Barrows Divergently Selected for ResidualFeed Intake
Animal Industry Report
  • Samaneh Azarpajouh, Iowa State University
  • Jessica Colpoys, Iowa State University
  • Emily Arkfeld, Iowa State University
  • Nicholas Gabler, Iowa State University
  • Anna Johnson, Iowa State University
  • Jack Dekkers, Iowa State University
  • Elisabeth Huff-Lonergan, Iowa State University
  • Steven Lonergan, Iowa State University
  • John Patience, Iowa State University
  • Kenneth Stalder, Iowa State University
Extension Number
ASL R3265
Publication Date
Summary and Implications

The objective of this experiment was to examine the behavioral metric correlations and growth performance of barrows divergently selected for residual feed intake (RFI) during a Human Approach Test. Forty low- (LRFI, more feed efficient) and 40 high-RFI (HRFI, less feed efficient) barrows from the 8th generation Yorkshire selection lines were randomly selected. Barrows were evaluated in a Human Approach Test for zone crossing, zone 1 (defined as the mouth, nose, and/or face of the pig contact any part of zone 1), escape, freeze, urination and defecation frequencies and their effect on performance measures. Within the HRFI line, urination frequency accounted for 18.5% of the variation in ADG and 10th-rib back fat at off test (r= 0.43; P = 0.01) and 26% of the variation in loin eye area off test (r=-0.51; P = 0.001). Within the LRFI line, behavioral metrics did not significantly correlate with performance measures (P ≥ 0.07). In conclusion, urination frequency was moderately correlated with ADG, 10th-rib backfat- and loin eye area in HRFI barrows during Human Approach Test. Therefore, within the context of the ISU swine genetic selection program for improved lean accretion and feed efficiency, there were no negative behavioral metrics that determinately affected performance measures during the grow-finish period

Copyright Holder
Iowa State University
Citation Information
Samaneh Azarpajouh, Jessica Colpoys, Emily Arkfeld, Nicholas Gabler, et al.. "Behavioral Associations during a Human Approach Test and Performance of Barrows Divergently Selected for ResidualFeed Intake" (2018)
Available at: