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Christina Moore

Characterization of Feeding Efficiency and Relationships with Ultrasound Carcass, and Feeding Behavior Traits in Brahman Bulls and Heifers

Moore, Christina; Paddock, Zachary; Mendes, Egleu; Carstens, Gordon; Forrest, David; Sterle, Jodi

Dept. Animal Science, Texas A&M University, College Station, TX

Christina Moore

Objective – Objectives of this study were to characterize feeding behavior traits, and to examine their relationships with performance and feed efficiency in growing Brahman bulls and heifers.

Animals or Sample Population – Growing Brahman bulls (n = 116) and heifers (n=134).

Procedure – The calves were fed a corn silage-based diet (ME = 2.78 Mcal/kg) and monitored over three 70-d tests using a Growsafe* feeding system to measure individual feed intake and feeding behavior traits. Residual feed intake (RFI) was calculated as the residual from the linear regression of dry matter intake (DMI) on mid-test body weight, BW^0.75 and average daily gain (ADG) within gender. Daily meal duration (min/d) and meal frequency (events/d) were averaged over the 70-d study, and eating rate (g/d) was computed as DMI divided by meal duration.

Results – Meal duration was positively correlated with frequency (0.16) and negatively correlated with eating rate (-0.55). ADG was positively correlated (P < 0.05) with meal duration (0.18), eating rate (0.22), but not with residual feed intake, RFI. Bulls had higher DMI than heifers (8.86 vs. 7.74 ± 0.16kg/day) and lower FCR than heifers (7.39 vs. 7.68 ± 0.48). Bulls had lower meal duration (101.87 vs. 119.31 ± 2.4), higher meal frequency (9.88 vs. 9.46 ± 0.21),and higher ADG (1.12 vs. 0.91 ± 0.02).

Conclusions and Clinical Relevance – Results from this study demonstrate a positive correlation between RFI and meal duration (0.37, p<.0001) and a negative correlation between RFI and meal frequency (-0.11, p=0.08), suggesting that feeding behavior traits may be used as indicator traits to predict RFI in beef cattle. Furthermore, bulls had lower FCR values than heifers (7.39 vs. 7.68 ± 0.48) and higher ADG values than heifers (1.12 vs. 0.91 ± 0.02), demonstrating that bulls are more efficient than heifers.