An essential oil blend fed for growth performance and carcass characteristics to feedlot steers.

Abstract

Some essential oils (EO) are known for having antimicrobial, antiviral, antifungal, and antioxidant characteristics that may be a feedlot antibiotic alternative to replace monensin sodium (M) and tylosin (T). Four-hundred cross-bred steers (BW 368.7 ± 11.0 kg) were blocked by initial BW and cattle source and randomly assigned to 1 of 5 treatments (8 pens/trt; 10 steers/pen) to evaluate an EO blend (EOB). Treatments were: 1) Control: no additives added to the steam-flaked corn-based finishing total mixed ration (TMR); 2) EOB: proprietary essential oil blend (Ralco Nutrition, Marshall, MN) added at 3 g/d; 3) EOB + M + T: EOB added at 3 g/d plus M and T (Huvepharma, Peachtree City, GA) at 42.4 and 8.5 g/ton, respectively; 4) M + T: M and T added at 42.4 and 8.5 g/ton, respectively; and 5) EOB + M: EOB and M added at 3 g/d and 42.4 g/ton. Individual BW were measured on two consecutive d at the start and conclusion and every 28 d during the experiment. Equal treatment pen replicates were transported to a commercial abattoir on 160, 174, and 182 d, respectively for collecting carcass data. Initial, interim 28-d periods, and final BW were similar (P > 0.50) among treatments However, during the 1^st 3 28-d time-period steers fed EOB along or in combination demonstrated greater average daily gain (ADG) compared with steers fed the remaining treatments. The study remaining time-periods and overall study ADG were similar (P > 0.10) for all treatments. Steers fed Control consumed greater (P < 0.05) overall study DMI compared with steers fed M + T with steers fed the remaining treatments being intermediate but different (P < 0.05) or similar (P > 0.05). Overall, study feed efficiency was lowest (P < 0.05) for steers fed Control compared with steers fed the remaining treatments being similar (P > 0.10). Dressing percentages were greater (P < 0.05) for steers fed EOB compared with steers fed the remaining treatments. Steers fed M + T demonstrated the lowest (P < 0.05) liver abscesses compared with steers fed Control and EOB with steers fed EOB + M + T being intermediate and similar (P > 0.10). Feeding finishing steers an EOB improved early growth rate and dressing percentage with similar feed conversions to M and T, but did not impact liver abscess incidences.