Evaluation of Maintenance Requirements and Dietary Energetics in Jersey Steers Feeding under Feedlot System

Two trials were conducted to evaluate maintenance energy requirements and feedlot growth performance of calf-fed Jersey steers. In trial 1, 30 Jersey calves (49.7±6.8 kg) were fed during the 524 d growing-finishing period to derive the maintenance coefficient (MQ). Overall, average daily gain (ADG, kg), dry matter in-take (DMI, kg), and gain-to-feed ratio (GF) were 0.76, 5.09, and 0.150, respectively. The derived MQ based on observed energy intake and ADG was 0.114, this value is 35% greater than 0.084 specified to Holstein steers. To validate the applicability of the MQ coefficient derived in Trial 1, we used 80 Jersey calves (101.5±4.1 kg), which were randomly assigned to diets containing 12 or 24% forage. Overall, steer per-formance measures for the 12 and 24% forage diets were ADG (0.96 vs. 0.99 kg, P=0.12), DMI (5.95 vs. 6.15 kg, P=0.04), and GF (0.166 vs. 0.156, P<0.01). Thus, the high-forage diet increased DMI and de-creased GF. Applying the MQ of 0.114 derived in Trial 1, the estimated dietary net energy (NE) for Trial 2 was in close agreement with the expected, averaging 1.02 and 1.00 for steers receiving the 12 and 24% for-age levels, respectively. It is concluded that the MQ of calf-fed Jersey steers is 35% greater than Holstein steers. Increasing dietary forage level to 24% decreased gain efficiency but did not appreciably affect daily weight gain.