Abstract:Different nutritional management during the rearing and finishing periods can determine changes on beef fatty acid profile. Beef lipid composition was quantified in 224 male Hereford calves weaned at 8 wk of age with an average initial live weight (LW) of 170 ± 17 kg. After weaning, 4 nutritional treatments were imposed to obtain different daily LW gains (LWG; kg/d) during the first winter. Nutritional management groups were high LWG in feedlot (HF), low LWG in feedlot (LF), high LWG in pasture (HP), and low LWG in pasture (LP). The finishing phase began when each group reached a mean LW of 350 ± 28 kg. During the finishing phase, one-half of the HF, LF, HP and LP animals were finished on pasture and the other half in a feedlot. The animals were slaughtered when calves in each treatment attained a mean LW of 500 kg. Analysis of beef fatty acids was performed by extraction and methylation from LM, and the fatty acids were quantified using a gas chromatography. The statistical model included the groups at growing phase (HF, LF, HP, and LP) and the groups at finishing phase (feedlot or pasture) and the interaction between growing and finishing phase as fixed effects and LW at the beginning of the finishing phase as a covariable. Tukey?s test was applied to compare the means (P