Feeding behavior during adaptation phase of beef cattle in feedlot reducing the use of conventional growth promoters

The aim this study was evaluate associations between feeding behavior and animal performance of feedlot cattle. Treatments were Control (CN - 24.4 mg/kg dry matter [DM] of monensin + 19.5 mg/kg DM of virginiamycin) and Standard (ST - 584.8 mg/kg DM of Fator P (R) + 12.2 mg/kg DM of monensin). Nellore young bulls (n=48), weighing 394.1 +/- 6.3 kg, were used, divided into twelve collective pens. Multivariate analysis by factor method using STATISTICA Multivariate Exploratory Techniques and General Linear Model analysis using STATISTICA Advanced Linear/Nonlinear Models, were developed. Considering total variability (63.65%), the Factor 1 had 35.19%), while Factor 2 had 28.46%. For Factor 1 there was association among average daily gain, feed efficiency and idle time, which were negatively associated to feed conversion and feeding time. There were no differences between treatments (P=0.28) for Factor 1. For Factor 2, there was a biological association between dry matter intake (DMI) and ruminating time (RT) which were negatively associate to nutrient apparent digestibility. There were differences between treatments for Factor 2 (P=0.01). Animals fed CN decreased DMI, reducing RT and increasing nutrient apparent digestibility compared to animals fed ST. These results can be due to the natural additive associated to a half of dosage of monensin not affect the DMI. There are biological association between feeding behavior and animal performance during adaptation phase of beef cattle in feedlot systems.