1368
Divergent selection for residual feed intake may be impacted by differences in feeding behaviour
Reduced activity related to feeding behaviour traits may explain the reduced feed intake and improved feed efficiency in low residual feed intake (LRFI) pigs, as less active animals will have a lower maintenance requirement. The objective of this study was to examine the effect of divergent selection for RFI on selected feeding behaviour traits. Male pigs (n=75; initial BW 22.42 kg (SD = 2.03)) were fed a standard finishing diet (12.5 g/kg lysine and 14.5 MJ/kg Digestible Energy)) for 43 days to evaluate feed intake and growth for the purpose of calculating RFI. Feeding behaviour was measured using electronic feeders that recorded consumption per visit and feeding time. Phenotypic RFI was calculated as the residuals from a regression model regressing DMI on ADG and midtest BW0.75 (MWT). Fifteen high RFI (HRFI) and 15 LRFI pigs were chosen for the purpose of examining feeding behaviour parameters. RFI was strongly correlated with both ADFI (r=0.67) and FCR (r=0. 73). LRFI pigs had lower ADFI (2.44kg vs. 1.87kg) and improved feed conversion ratio (1.96 vs. 2.48) relative to HRFI pigs (P<0.001) with no difference in ADG or MWT. Behavioural analysis indicated that LRFI pigs ate less (P<0.0001), spent less time eating per day (P<0.05), had smaller meals (P=0.05) and spent less time eating each meal than HRFI pigs (P=0.09). LRFI pigs had less variation in there time spent eating (P=0.09) than HRFI pigs, indicating that LRFI pigs had a more consistent feeding pattern. There was interactions between residual feed intake and the number of visits per day (P<0.05) with LRFI pigs having fewer visits to the feeder than HRFI pigs across the experimental period. The results from this study suggest that LRFI pigs have lower activity related to feeding actions. This may partly explain the reduced feed intake in LRFI pigs.
Keywords:
Residual Feed Intake: Feeding Behaviour: Pigs