Effects of alternative feed additives and flint maize grain particle size on growth performance, carcass traits and nutrient digestibility of finishing beef cattle

Abstract

The current study evaluated growth performance and digestion responses of finishing bulls fed diets containing 825 g/kg flint maize [dry matter (DM) basis] ground to medium (1.66 mm; MG) or coarse particle sizes (2.12 mm; CG), with added monensin (26 mg/kg; DM basis; MON) or a blend of essential oils (BEO) + exogenous α-amylase (AM; 90 mg/kg + 560 mg/kg commercial product, respectively, DM basis). In Expt 1, 256 Nellore bulls were blocked by initial body weight (BW) (360 ± 11.7 kg) and assigned to 48 pens in a 2 × 2 factorial arrangement of treatments. Effect of a maize particle size × feed additive interaction was not detected for final BW, DM intake (DMI), average daily gain (ADG) and feed efficiency. The DMI was greater for bulls fed BEO + AM v. MON. Final BW and ADG tended to be greater for bulls fed CG than MG maize. An interaction was detected for hot carcass weight which was 11 kg heavier for bulls fed BEO + AM v. MON in diets containing CG, but not MG particle size. In Expt 2, four ruminally cannulated Nellore steers were offered the same treatments as Expt 1, in a 4 × 4 Latin Square design. Intake of most nutrients was greater for steers fed CG than steers fed MG maize. In summary, feeding bulls CG maize increased growth performance and carcass characteristics compared with MG. The combination of BEO + AM resulted in heavier carcass weights compared with MON supplementation when included in diets containing CG maize.

Blend of Essential Oils Supplemented Alone or Combined with Exogenous Amylase Compared with Virginiamycin Supplementation on Finishing Lambs: Performance, Dietary Energetics, Carcass Traits, and Nutrient Digestion

“…Consistent with Gouvêa et al [ 44 ], the combination EO + ENZ did not affect apparent total tract digestion of OM, starch or NDF. Lack of treatment effects on total tract starch digestion is not surprising, in as much as apparent total tract starch digestion approached 100% for all treatments.…”

“…Lack of treatment effects on carcass traits and tissue composition is consistent with previous comparisons of supplemental EO [ 8 , 43 ], EO + ENZ combination [ 44 ], and VM [ 39 ].…”

Feed intake, nutrient digestibility, and selected rumen parameters in feedlot bulls fed diets with different feed additives

“…Gouvêa et al [ 13 ] and Meschiatti et al [ 14 ] reported an increase in feed intake (7.4 and 8.6%, respectively) when MON was replaced by EOA. However, according to Gouvêa et al [ 13 ], the roughage source may affect the DM intake when EOA is provided.…”

“…The dietary inclusion of ionophores and non-ionophores as sole feed additives or in combination has increased propionic acid production, improved feed efficiency, and reduced the incidence of metabolic disorders compared to diets containing no additives [ 11 , 12 ]. However, plant compounds with antibacterial properties and exogenous enzymes have been increasingly used to replace antibiotics in feedlot diets [ 13 , 14 ]. In this context, studies [ 13 , 14 ] have shown that animals fed diets containing essential oils plus exogenous α-amylase (EOA) may show increased feed intake, starch digestibility, and average daily gain compared to those fed diets with other feed additives, such as MON.…”

“…However, plant compounds with antibacterial properties and exogenous enzymes have been increasingly used to replace antibiotics in feedlot diets [ 13 , 14 ]. In this context, studies [ 13 , 14 ] have shown that animals fed diets containing essential oils plus exogenous α-amylase (EOA) may show increased feed intake, starch digestibility, and average daily gain compared to those fed diets with other feed additives, such as MON.…”