Animal Industry Report

Extension Number

ASL R2641



Summary and Implications

The objective of this study was to determine the effect of selection for reduced feed intake (RFI) on scale activity for Yorkshire gilts. A total of 192 Yorkshire gilts were used, 96 were from a line that had been selected for low residual feed intake over 5 generations (LRFI) and 96 from a randomly bred control line (CRFI). Gilts were housed in 12 pens (16 gilts/pen; 0.82 m2/gilt) containing 8 gilts from each line in a conventional grow-finish unit. Gilts were weighed every 2-wks for a maximum of eight scores per gilt. Gilts were scored while on the weigh scale for activity using a whole number scale of one to five (1 = calm, minimal movement; 5 = continuous rapid movement and an escape attempt). Analyses were done using Proc Mixed of SAS. The LRFI line began with a lower scale activity score, but did not experience as great of a drop in their score as the CRFI gilts. The CRFI gilts scored lower by the end of the rounds compared to the LRFI gilts. In conclusion, selection for lower residual feed intake in purebred Yorkshires has a related effect on scale activity score but this relationship is complicated and thus warrants further research. Therefore, scale activity may not be an easy measure to be added to the list of already described traits in pigs as a factor which relates to selection for lower RFI.

Copyright Holder

Iowa State University