PSXIII-13 - Effect of supplementation of red osier dogwood extract on feed intake and growth performance of newly weaned beef calves

Abstract: Red osier dogwood (ROD) is a Canadian native shrub plant that is rich in phenolic compounds with antimicrobial and antioxidant properties. The high phenolic compounds with antimicrobial and antioxidant properties would be beneficial to reduce oxidative stress, hence improve animal growth performance when animals are stressed. The objective of this study was to evaluate the effects of feeding ROD extract the residue after extraction to newly weaned calves on feed intake and growth performance. Eighty crossbred Angus steers (initial body weight [BW], 254 ± 5.4 kg) were used and housed in individual feedlot pen. The experiment was a randomized complete block design in five treatments (16 steers/treatment). Five treatments were: 1) Control (without ROD); 2) 20 g/d ROD extract (RODLow); 3) 40 g/d ROD extract (RODHigh); 4) 100 g/d ROD residue (RODRes); and 5) 330 mg monensin/d (MON). The MON was used as positive control because it is commonly fed to feedlot cattle to improve feed efficiency and animal health. The experiment diet consisted of 60% silage and 40% concentrate (DM basis) with 84 d long. The DPPH free radical scavenging activity of ROD extracts and the residue after extraction were determined. The high DPPH scavenging was observed for both ROD extracts (60.6 ± 4.7%) and residue (80.6 ± 1.7%) at the concentration of 0.5mg/mL. Dry matter (DM) intake (kg/d) overall did not differ between control (6.44) and ROD supplemented calves (average, 6.27), whereas the DM intake tended (P = 0.10) to be greater with ROD extract (4.97 kg/d) than control (4.56 kg/d) at the first 28 d. The final BW, averaged daily gain and feed efficiency were not affected by increasing dose of ROD extract (0, 20, 40 g/d) or by adding 100 g/d ROD residue. The calves fed MON had lower (P = 0.04) DM intake (5.72 vs. 6.32 kg/d) and lower (P = 0.07) daily gain (0.81 vs. 0.94 kg/d) than other treatments. Fecal pH ranged from 6.98 to 6.17, and did not differ among treatments. These results indicate that feeding ROD extract or its residue to newly weaned calves may increase feed intake when the animal are in stressful, however its effect on growth performance and feed efficiency is not apparent under current feeding conditions.