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dc.contributor.advisorCarstens, Gordon E
dc.contributor.advisorTedeschi, Luis O
dc.creatorMoreno Rajo, Jose Gilberto
dc.date.accessioned2013-10-02T21:27:52Z
dc.date.available2015-05-01T05:57:08Z
dc.date.created2013-05
dc.date.issued2013-01-14
dc.date.submittedMay 2013
dc.identifier.urihttps://hdl.handle.net/1969.1/149277
dc.description.abstractObjectives of this study were to characterize feed efficiency traits and examine phenotypic relationships with feeding behavior traits in bulls. Performance, feed intake and feeding behavior traits were measured in bulls (n = 5,165) representing 2 breeds (4100 Angus and 952 Red Angus). Intake and feeding behavior traits were measured for 70-d using a GrowSafe system while fed a corn silage based diet (ME = 2.50 Mcal/kg DM). BW was measured at 14-d intervals. Residual feed intake (RFI) was calculated as the difference between actual DMI and that expected from regression of DMI on mid-test BW0.75 (MBW) and ADG, and residual gain (RG) as the difference between actual ADG and that expected from regression of ADG on MBW and DMI. Residual gain and intake (RIG) was computed as the sum of -1 x RFI and RG, both standardized to a variance of 1. Results from the study indicate that RFI was correlated with DMI (r = 0.71, P < 0.0001) but not MBW or ADG, whereas, RG was correlated with ADG (r = 0.87, P < 0.0001) but not MBW or DMI. RFI was negatively correlated with G:F (r = -0.53, P < 0.0001) and RG (r = -0.40, P < 0.0001). Feeding bout (FB) frequency and duration were correlated with RFI (r = 0.30, 0.36; P < 0.001), but were not significant or weakly correlated (r < 0.10) with RG and G:F. Meal criterion and duration were both correlated (r = -0.13, 0.22; P < 0.0001) with RFI, but not with RG or G:F. Bulls with low RFI spent less time at the feed bunk (129 vs 151 ± 31.2 min/d) and had fewer FB events (79 vs 91 ± 23.4 events/d) than high-RFI bulls. Low-RFI bulls had longer (P < 0.001) meal criterion (9.9 vs 8.5 ± 6.6 min) indicating they took longer to initiate new meals, and had longer meal durations (223 vs 244 ± 43.5 min/d) than high-RFI bulls. Bulls have distinctive feeding behavior patterns that contribute to between-animal variation in RFI, but not associated with RG or G:F.en
dc.format.mimetypeapplication/pdf
dc.subjectfeeding behavioren
dc.subjectResidual feed intakeen
dc.subjectResidual gainen
dc.subjectResidual intake and gainen
dc.subjectFeedlot profit indexen
dc.titlePhenotypic Characterization of Feed Efficiency and Feeding Behavior Traits in Performance Tested Bulls Fed a Corn Silage-Based Dieten
dc.typeThesisen
thesis.degree.departmentAnimal Scienceen
thesis.degree.disciplineAnimal Scienceen
thesis.degree.grantorTexas A&M Universityen
thesis.degree.nameMaster of Scienceen
thesis.degree.levelMastersen
dc.contributor.committeeMemberForrest, David E
dc.type.materialtexten
dc.date.updated2013-10-02T21:27:52Z
local.embargo.terms2015-05-01


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