340 Impact of essential oils blend on beef cattle performance and carcass characteristics in diets with increasing corn silage inclusions

Abstract

Abstract A feedlot study was conducted comparing a natural feed additive (essential oils blend) at varying silage inclusions on receiving and finishing performance. The study utilized 480 crossbred steers (initial shrunk BW 296 kg ± 7.72 kg) in 48 pens with 10 steers/pen and 8 pens per treatment. Treatments were designed as a 2 × 3 factorial with 3 inclusions of corn silage [14, 47, 80 %; dry matter (DM) basis] with or without (+, -) the inclusion of an essential oils (EO) blend. All treatment diets contained 16% modified distillers grains plus solubles and 4% supplement with dry-rolled corn replacing corn silage (CS) on a DM basis. Steers were fed at 80% CS inclusion and adapted to 47% and 14% CS over a 10 and 24-d period, respectively. Cattle fed 80% CS were fed for 238 days, 47% CS for 195 days, and 14% CS were fed for 168 days to a common backfat of 1.28 cm (P > 0.59). There were no interactions for corn silage inclusion and the inclusion of essential oils on final body weight (FBW), dry matter intake (DMI), average daily gain (ADG), gain to feed ratio (G:F), hot carcass weight (HCW), longissimus muscle (LM) area, marbling, or calculated yield grade (CYG; P > 0.15). There was no significant difference for FBW, DMI, ADG, G:F, HCW, LM area, marbling, or CYG for cattle fed EO or no EO. However, there was a quadratic response for FBW, ADG, G:F, HCW, marbling and CYG with increased inclusion of corn silage (P < 0.04). Feeding corn silage at greater inclusions decreased animal performance but increased final body weight when fed to an equal fatness. Essential oils did not affect animal performance or carcass characteristics. However, feeding greater amounts of corn silage can be an economical way to finish cattle.