Influence of Live Weight Gain During the Winter Grazing Period on Subsequent Grazing and Feedlot Performance

Abstract

Crossbred steer (n = 297) and heifer (n = 125) calves were used in three experiments to determine the impact of restrictive ADG during the winter grazing period on subsequent BW gains. Calves were born in the spring, weaned in the fall, and transported from Northwest Arkansas (360 km; Experiments 1 and 2) or Southwest Texas (880 km; Experiment 3) to Central Oklahoma for grazing and finishing. Upon arrival, calves were assigned to one of the following treatments: 1) grazing winter wheat pasture, 2) grazing dormant tallgrass native prairie plus supplemental CP, or 3) limit fed a high-energy diet (Experiment 3 only). In March, winter stocker treatments (121 d) were ended, and calves grazed cool season grasses (76 d) until June when the feedlot phase began. In the feedlot phase, calves were either assigned to a conventional total confinement finishing system or to a warm-season grass pasture managed under intensive early stocking (9.9 calves/ha) followed by ad libitum access to a high-energy diet. In Experiments 1 and 2, calves on dormant native pasture gained less (P<0.01) BW during the winter than calves on wheat pasture (15.8 vs 97.2 kg). Restricting winter ADG did not affect BW gains during the spring grazing period, but did increase (P<0.01) feedlot ADG by 23.5%. Performance of calves used in Experiment 3 was similar to that observed for Experiments 1 and 2. Calves finished on pasture had greater (P<0.01) net returns than calves finished in confinement (-$34.45 vs -$51.62 per calf). Restricting winter ADG of stocker calves increased ADG and feed efficiency during the feedlot phase. A production system that includes intensive early stocking of warm-season grass pastures followed by ad libitum access to a high-energy diet can be used to produce finished beef carcasses more economically than under total confinement.