27 A phytogenic additive improves performance of feedlot beef cattle compared with the use of sodium monensin.

Abstract Our objective was to evaluate the effects of a phytogenic feed additives on feed intake and performance of high-concentrate diets on feedlot cattle, compared with to sodium monensin. A total of 224 Nellore bulls (iBW: 413.8 ± 9.76kg, 20 mo old) were allocated to collective pens (7 animals/pen) in a randomized block design, considering the pen as the experimental unit (7 pens/treatment), distributed across four treatments: MON) Sodium monensin (Rumensin® Elanco, 26 mg/kg DM); BEO) Blend of essential oils (CRINA® Ruminants, dsm- firmenich, 90 mg/kg DM); PHY) Phytogenic additive (Digestarom® Prime, dsm- firmenich, 90 mg/kg DM); BEO+PHY) BEO 80 mg/kg DM + PHY 80 mg/kg DM. Feed intake and performance were evaluated in two phases: Initial (days 1-26) and Overall (Days 1-101). Animals were weighed after 14±2 h fasting at the start and end of the experiment, with an additional measurement on day 26, a 4% deduction was applied for gastrointestinal contents. Six animals were slaughtered at the start of the experiment to estimate initial carcass weight, while the remaining were slaughtered after 101 days of feeding. Data were analyzed using the PROC MIXED in SAS®, with Tukey’s test α = 5%) for mean comparisons. In the initial phase, PHY and BEO demonstrated greater DMI, BEO did not differ from BEO+PHY and MON had the lowest feed intake (p< 0.05). PHY and BEO had greater ADG than MON, while BEO+PHY did not differ from the other treatments (p< 0.05). On day 26, BW was higher for PHY than MON, while BEO and BEO+PHY were like the other treatments (p< 0.05). Feed efficiency was unaffected in the initial phase (0.206±0.001, p=0.37). On overall performance, PHY showed greater DMI than MON (11.95 vs. 10.83 kg/d, p=0.008), while BEO and BEO+PHY did not differ from either. PHY also had higher ADG than MON and BEO+PHY (1.66 vs. 1.51 kg/d, p=0.01), whereas BEO did not differ from the other treatments. Feed efficiency was not affected by the additives (0.138±0.005, p=0.21). Final BW followed the same trend as ADG overall (p=0.004). There was no effect of the additives on dressing percent (58.2±0.25%, p=0.36) or carcass conversion efficiency (135±4.21 kg DM/15 kg carcass produced, p=0.78). PHY resulted in greater HCW (338.9 vs. 326.2 kg, p=0.02) and higher carcass ADG (1.34 vs. 1.21 kg/d, p=0.02) compared to MON, while BEO and BEO+PHY did not differ from the other treatments for these traits. In conclusion, feeding phytogenic feed additive improves feed intake and carcass weight, and thereby can dismiss the use of antibiotic growth promoter in feedlot finishing diets.