254 Evaluation of Different Corn Milling Methods for High-moisture and Dry Corn on Finishing Cattle Performance and Carcass Characteristics

Steers (n=600; Initial BW = 402 ± 17 kg) were fed for134 day to evaluate the effect of milling method and corn type on performance and carcass characteristics. Treatments were evaluated as a 2 × 3 factorial with factors being milling method (Automatic Ag® roller mill or hammer mill) and corn type (100% high-moisture, 100% dry, or 50:50 blend of high-moisture and dry corn). High-moisture corn was processed at harvested based on respective treatment and ensiled until trial initiation. Both dry corn and HMC were processed using a 16-mm screen in the hammer mill and the roller mill was adjusted to ensure all kernels were broken. There were no interactions between milling method and corn type for final BW, daily gain (ADG), or dry matter intake (DMI; P ≥ 0.32), but there was a tendency for an interaction for G:F (P = 0.09). Cattle fed 100% high-moisture corn processed with the Automatic Ag roller mill were 4.7% more efficient (P ≤ 0.01) with 55% lower fecal starch (P < 0.01) compared to high-moisture corn processed with the hammer mill. Cattle fed dry corn tended (P = 0.07) to have a greater live final BW regardless of milling type and had the greatest DMI (P ≤ 0.01) Intake decreased as high-moisture corn was increased in the diet. Due to no differences in ADG with lower DMI led to a 6% improvement (P ≤ 0.01) in G:F for steers fed HMC. There were no further effects (P ≥ 0.14) on performance or carcass traits regardless of milling method or corn type. Processing high-moisture corn using Automatic Ag roller mill improved feed efficiency compared to processing with a hammer mill when corn was included at 70% of the diet, but processing method had little effect when fed as dry corn or blended diets.

High-moisture corn grain silage inoculated with Propionibacterium acidipropionici and Lactobacillus plantarum in different storage times

The aim of this study was to evaluate the chemical composition, growth of microorganisms, and the aerobic stability of high-moisture corn grain silage inoculated with Lactobacillus plantarum + Propionibacterium acidipropionici. The experimental design was completely randomized in a 2 x 5 factorial arrangement with four replications (50 experimental units) and the treatments were: use or not of microbial inoculant (2 x 105 colony forming unit (CFU) g-1 Lactobacillus plantarum + Propionibacterium acidipropionici) and the storage length for 0, 1, 3, 7, and 14 d. Aerobic stability of silage was evaluated at 28 and 56 d of storage length. The lactic acid bacteria population was influenced by storage length and the greatest values were estimated at 8 d of storage length. Regardless of inoculant application, no enterobacteria were present from 3 d post-ensiling. With respect to mold growth, an interaction between inoculant and storage length was observed wherein molds were most abundant after 3 d of storage in silage that received inoculant. However, at 14 d of storage the use of bacterial inoculant reduced the occurrence of molds. pH values obtained after 3 d of ensiling were less than 4.0 for all the treatments. The high-moisture corn grain silage possessed good fermentative quality. Further, adequate pH values were achieved from the third day of ensilage and were not influenced by the presence of bacterial inoculant.

198 Ruminal pH of Angus and Nellore steers during adaptation to high-energy diets with different nutritional strategies

The objective of this study was to evaluate the effect of adding monensin into high-concentrate diets based on either finely-ground or high-moisture corn during the transition from adaptation to finishing diets on ruminal pH of cannulated Angus and Nellore steers. Four 30-mo-old Nellore and four 30-mo-old Angus steers were divided (± 550 kg) into two 4 x 4 Latin squares, where each square was composed by animals from same breed, and randomly submitted to a 2 x 2 factorial arrangement of treatments as follows: T1) Finely-ground corn + monensin; T2) Finely-ground corn; T3) High moisture corn + monensin; T4) High-moisture corn. Periods were divided as follows: 14 days of adaptation diets and 18 days of finishing diet (80% concentrate). The study lasted 149 days, including three 7-d washout intervals. The rumen pH was assessed continuously via data loggers on days 4, 8, 12, 16, 20, 24 and 28. Interactions between breed and days were observed for DMI (P = 0.02) and pH duration below 5.6 (P = 0.01), where Angus steers had greater DMI and spent a longer time below 5.6 than Nellore animals on days 12, 16, 20, 24 and 28. The addition of monensin decreased (P = 0.01) DMI on days 16, 20, 24 and 28. Regarding pH duration and area below 5.6, an interaction between breed and corn was observed (P = 0.001), in which Angus steers fed finely-ground corn spent a longer time (416 min/day) and had a larger area (224.6 min x pH units/day) below 5.6 than animals from other treatments. For mean pH, steers consuming high-moisture corn had higher pH (6.45 vs. 6.29); and an interaction was observed (P = 0.03) between breed and monensin, where monensin addition decreased pH for Angus (5.96 vs. 6.18), but not for Nellore steers (6.68 vs. 6.63). The feeding of monensin and finely-ground corn did not positively impact rumen pH of Angus steers.

227 Impact of feeding Aspergillus subspecies (ssp.) blend and different corn processing methods on finishing beef cattle performance and carcass characteristics

The objective of this study was to evaluate the effect of feeding Aspergillus ssp. blend in combination with dry-rolled (DRC) or high-moisture corn (HMC) based finishing diets on performance and carcass characteristics. Crossbred beef steers (n = 320; initial BW = 267 ± 9 kg) were utilized in a generalized randomized block design. Cattle were assigned randomly to pens by initial body weight (BW) and pens were assigned randomly to one of four treatments with 8 pens per treatment for simple effect means. Treatments were set up as a 2 × 2 factorial arrangement with factors consisting of corn processing and 0 g / steer daily or 10 g / steer daily Aspergillus ssp. blend. There were no significant interactions (P ≥ 0.23) observed between corn processing and Aspergillus ssp. blend in the diet; therefore, only main effects are discussed. For the main effect of Aspergillus ssp. blend; no significant differences were observed for dry-matter intake (DMI), average daily gain (ADG), feed efficiency (G:F), hot carcass weight (HCW), or carcass traits (P ≥ 0.78). Cattle fed Aspergillus ssp. blend had a greater 12th rib fat (P = 0.05). For the main effect of corn processing, cattle fed DRC had heavier HCW and final BW (P = 0.04), greater ADG (P = 0.05), and greater DMI (P < 0.01). However, steers fed HMC had greater G:F (P < 0.01) compared to DRC. These data suggest that feeding Aspergillus ssp. blend in either with dry-rolled or high moisture corn diets did not significantly improve performance or carcass characteristics in finishing beef steers. While feeding HMC improved feed efficiency compared to DRC, feeding DRC increased ADG (and also DMI) compared to HMC.

Rehydration of dry corn preserves the desirable bacterial community during ensiling

ABSTRACT This study evaluated the rehydration approach of mature corn grains as an alternative for high-moisture corn grain silage production in distinct corn hybrids, storage period, cultivation locations and kernel maturity at plant harvest. High-moisture corn was used as a control. The dry matter content and pH of the silage were measured, and the bacterial community associated with corn grains pre- and post-ensiling was also assessed through 16S rRNA high-throughput sequencing. The decrease in pH value was directly linked to an ecological microbial succession of Enterobacteriales and Actinomycetales to Lactobacillales in the silage at 120 days after storage, either in rehydrated or high-moisture corn. These results were similar for both maize production locations and hybrids tested. Finally, the similarity between the ensiling processes including rehydrated corn and the high-moisture corn grain silages proves the reliability of the rehydration approach as an alternative for the maintenance of a successful bacterial community structure and composition capable of producing high-quality silages from dent and flint corn hybrids in tropical conditions.

Fibrolytic enzymes improve the nutritive value of high-moisture corn for finishing bulls

Exogenous fibrolytic enzymes (EFE) improve the energy availability of grains for nonruminant animals by reducing encapsulation of the endosperm nutrients within grain cell walls; however, these benefits are unknown in the treatment of corn-based silage for cattle. The objective of the present study was to evaluate the effects of adding EFE at ensiling on the nutritive value of high-moisture corn (HMC) and snaplage (SNAP) for finishing Nellore bulls. The EFE dose was 100 g/Mg fresh matter in both HMC and SNAP. Diets were 1) a SNAP + HMC control (without enzyme addition); 2) SNAP + HMC EFE (with enzymes); 3) a whole-plant corn silage (WPCS) + HMC control (without enzyme addition); and 4) WPCS + HMC EFE (with enzymes). In addition to the silages, the diets were also composed of soybean hulls, soybean meal, and mineral–vitamin supplement. The statistical design was a randomized complete block with a factorial arrangement of treatments, and the experiment lasted 122 d. For in situ and in vitro analyses, 2 cannulated dry cows were used. There was no interaction between the diets and EFE application (ADG, P = 0.92; DMI, P = 0.77; G:F, P = 0.70), and there was no difference between the SNAP and WPCS diets regarding the DMI (P = 0.53), ADG (P = 0.35), and feed efficiency (ADG:DMI, P = 0.83). Adding EFE to the HMC and SNAP at ensiling did not affect ADG but decreased DMI (P = 0.01), resulting in greater feed efficiency by 5.91% (P = 0.04) than that observed in animals fed diets without the addition of EFE. Addition of EFE to HMC resulted in reduced NDF content and increased in vitro and in situ DM digestibility compared with untreated HMC. No effects were found for the addition of EFE to SNAP. Fecal starch decreased with EFE application (P = 0.05). Therefore, the diet energy content (TDN, NEm, and NEg) calculated from animal performance increased (P = 0.01) with the addition of EFE to HMC. In conclusion, exchanging the NDF from WPCS with that from SNAP did not affect the performance of finishing cattle, whereas the addition of EFE to HMC at ensiling improved animal performance by increasing the energy availability of the grain.