The objective of this work was to evaluate the productive efficiency of beef cows. Thirty Angus and 32 Charolais primiparous cows, pregnant at the beginning of the experiment with straightbred or crossbred calves, were evaluated. The cows were submitted to different feeding management during winter and spring: T1 -- Native pasture, T2 -- Cultivated pasture for 60 days (24 hours/day), from early September to early November, T3 -- Cultivated pasture for two hours a day, for 60 days, from early July to early September, T4 - Cultivated pasture for two hours a day, for 60 days, from early July to early September, and more 60 days on cultivated pasture (24 hours/day), from early September to early November. Productive efficiency was measured by CALVINGPE = (W205/CWC)*100, WEANINGPE = (W205/CWW)*100, CALVINGMBPE = (W205/CWC.75), WEANINGMBPE = (W205/CWW.75) and TDNPE = TDNTOTAL/W205, where W205 is the calf weaning weight and CWC and CWW are the cow weight at calving and weaning, respectively. TDNTOTAL is the total energy requirement (maintenance + milk production) of the cow. Aberdeen Angus cows, cows with male calves and cows with crossbred calves were more efficient. Cows that had access to cultivated pasture for a long period of time (T4) had better performance than those that were maintained on native pasture only (T1). Cows of the other treatments had intermediate performance.
beef cattle; crossbreeding; milk; productivity; weight
