Feed Intake and Feeding Behavior Associations with Performance and Feed Efficiency of Feedlot Cattle Fed a Corn-based Diet

The objective of the first study was to determine which combination of bimodal (2-population) distribution models best fit non-feeding interval data to distinguish intervals within (1st population) and between (2nd population) meals in beef cattle fed a corn-based diet. Feeding behavior traits were measured in 119 heifers fed a corn-based diet using a GrowSafe system. Bimodal distribution models were fitted to the log10-transformed interval lengths between bunk visit (BV) events for each animal using Gaussian (G); Weibull (W); Log-Normal; Gamma and Gumbel statistical functions. Criterion (AIC) and likelihood probability estimates.

Objectives of the second study were to quantify individual meal criterion and examine the associations between feeding behavior traits, performance, and feed efficiency traits in heifers fed a corn-based diet.

Results from study one indicate that the G-W bimodal distribution model is a statistically better fitting and likely a more appropriate model to define meal criterion compared to the standard G-G model used in previous literature.

Results from the second study suggest that the meal criterion for heifers fed a corn-based diet is 11.48 min when applying the G-W bimodal model to log-transformed interval lengths between BV events. Moderate phenotypic correlations between feed efficiency (residual feed intake- RFI) and several feeding behavior traits were found. Inclusion of these feeding behavior traits to the base model for RFI accounted for an additional 25% of the variation in DMI not explained by ADG or mid-test BW0.75. Significant (P < 0.05) differences in 11 observed feeding behavior traits between RFI classification groups were also found suggesting that differences in feeding behaviors may contribute to the variation in RFI due to differences in energetic costs related to feeding activities.