Proportions of Concentrate and Corn Silage Rehydrated Ground Grain at Different Storage Times for Better Use of Starch by Lambs

The objective of this study was to evaluate the nutritional and bioeconomic potential of corn silage, rehydrated ground grain corn silage (RCGS), at different storage times associated with proportions of concentrates for better starch utilization by sheep. Forty Dorper-Santa Inês crossbred sheep were used, with an average body weight of 24 kg ± 3.9 kg, and an average age of 60 days. The sheep were confined for 63 days and distributed entirely at random with eight sets of repetitions and five experimental diets: Diet 1: ground corn dry; Diet 2: proportion of 850 g / kg of concentrate + rehydrated ground grain corn silage (RCGS) stored for 45 days; Diet 3: proportion of 650 g / kg of concentrate + RCGS stored for 90 days; Diet 4: RCGS stored for 45 days + 650 g/kg concentrate; Diet 5: RCGS stocked with 90 + 850 g/kg concentrate. As roughage, silage corn whole plant. Starch intake was higher (P<0.05) with the dry ground corn diet, however, digestibility was lower (P<0.05) for most nutrients compared to the RCGS diet. A smaller amount of starch was found in the feces of animals that received the RCGS diet. RCGS stored for 45 days and the diet with 650 g/kg of concentrate generates greater net income, increases nutrient intake, it is an alternative during the fluctuation of corn prices.

Tannic Acid-Steeped Corn Grain Modulates in vitro Ruminal Fermentation Pattern and Microbial Metabolic Pathways

This study investigated the effects of tannic acid (TA)-treated corn on changes in ruminal fermentation characteristics and the composition of the ruminal bacterial community in vitro. Ruminal fluid was obtained from three rumen-fistulated goats fed a 60:40 (forage/concentrate) diet. The batch cultures consisted of 25 ml of strained rumen fluid in 25 ml of an anaerobic buffer containing 0.56 g of ground corn, 0.24 g of soybean meal, 0.10 g of alfalfa, and 0.10 g of oat grass. Ground corn (2 mm) was steeped in an equal quantity (i.e., in a ratio of 1:1, w/v) of water alone (Con), 15 (TA15), 25 (TA25), and 35 g/l (TA35) TA solution for 12 h. After incubation for 24 h, TA-treated corn linearly increased (P &lt;0.05) ruminal pH and the molar proportion of acetate, but linearly reduced (P &lt;0.05) total volatile fatty acids and the molar proportion of butyrate compared with the Con treatment. Illumina MiSeq sequencing was used to investigate the profile changes of the ruminal microbes. A principal coordinates analysis plot based on weighted UniFrac values revealed that the structure of the ruminal bacterial communities in the control group was different from that of the TA-treated corn groups. The results of changes in the rumen bacterial communities showed that TA-treated corn linearly enriched (P &lt;0.05) Rikenellaceae_RC9_gut_group, but linearly reduced (P &lt;0.05) Ruminococcaceae_NK4A214_group, Ruminococcus_2, and unclassified_o__Clostridiales. Functional prediction of ruminal microbiota revealed that the TA-treated corn linearly decreased ruminal microbiota function of utilizing starch through pyruvate metabolism. In conclusion, TA-treated corn can modulate the rumen fermentation characteristics, microbial composition, and metabolic pathways, which may be potentially useful for preventing the occurrence of ruminal acidosis.

PSX-B-2 Effect of feedlot days on intake and performance of Nellore heifers

The objective was to evaluate the effect of feedlot days (FD) on intake (DMI) and performance of Nellore heifers. Fifty-one Nellore heifers [325±19.3 kg of body weight (BW); 16±1 months], blocked by initial BW and stratified by carcass ultrasound, were divided into three treatments: 45, 75 or 105 FD; and placed in 18 pens [17 heifers/treatment; 6 pens/treatment (5 pens with 3 heifers and 1 pen with 2 heifers)]. The animals were fed ad libitum allowing 3% of refusals. The diet consisted of corn silage, ground corn, soybean meal, protected fat and minerals. The adaptation diet [16% CP and 79% TDN; roughage:concentrate (R:C) = 44:56] was offered from day 1 to 15 and the finishing diet from day 16 to 105 (14.5 % CP and 86% TDN; R:C = 25:75). At the end of each FD, heifers were weighted to obtain the shrunk final BW and slaughtered in the same slaughterhouse. The final BW and hot carcass weight (HCW) were greater (linear effect; P ≤ 0.01), respectively, for heifers on 105FD (442 and 244 kg) compared to 75FD (411 and 228 kg) and 45FD (374 and 206 kg). The DMI, backfat thickness and longissimus area increased over FD (linear effect; P ≤ 0.01; 45FD = 7.10 kg/d, 5.05 mm and 64.3 cm2; 75FD = 7.68 kg/d, 5.69 mm and 68.5 cm2 and 105FD=7.79 kg/d, 7.04 mm and 73.3 cm2). The FD did not affect carcass gain (P = 0.38) and feed efficiency based on carcass gain (P = 0.84). However, total carcass gain increased over FD (linear effect; P ≤ 0.01; 29, 51.4 and 75.9 kg, respectively to treatments 45, 75 and 105 FD). In conclusion, the feedlot days increase the BW, backfat thickness and longissimus area. However, the feed efficiency based on carcass gain does not reduce when the heifers are submitted for a long time on feedlot.

236 Effects of Saccharomyces Cerevisiae Fermentation Products (SCFP) and Subacute Ruminal Acidosis (SARA) on Co-occurrence Patterns and Hub Taxa of Rumen Liquid Microbiota in Lactating Dairy Cows

Thirty-two dairy cows receiving a basal diet containing 34.9% NDF, and 18.6 % starch, were randomly assigned to four treatments: supplementation either with 140 g/d of ground corn (Control), 126 g/d of ground corn and 14 g/d of XPC (SCFPa, Diamond V Original XPC Cedar Rapids, IA), 121 g/d of ground corn and 19 g/d of NutriTek (SCFPb-1x, NutriTek, Diamond V), or 102 g/d of ground corn and 38 g/d of NutriTek (SCFPb-2x) from 4 wk before until 12 wk after calving. SARA was induced during wk 5 and wk 8 after calving by replacing 20% of the basal diet with pellets containing 50% barley and 50% wheat. Ruminal fluid samples were collected at 6 h after feeding on the second day of wk 4 to wk 10 after calving. Weeks 4, 7 and 10 were considered to be non-SARA. Microbial DNA was extracted, llumina sequenced at the V1–V2 regions of the 16S rRNA gene, and operational taxonomic units (OUT) were assigned using QIIME2. Correlation network analysis (CoNet) determined connections between the relative abundances of OTU, including co-occurrences, and to identify hub OTUs with over 15 connections with other OTUs. The degree of connectedness of phyla was normalized as the total number of positive and negative correlations observed for each phylum divided by their relative abundance in the community. In the Control treatment, SARA reduced positive degree of connectedness (19.33 vs 11.95). In all SCFP treatments, SARA increased the positive degree of connectedness (SCFPb-2x: 25.73 vs 23.50, SCFPb-1x: 87.47 vs 116.32, SCFPa: 34.01 vs 51.56). The relative abundances of the hub taxa Bacteroidales RF16 group and Lachnospiraceae, Christensenellaceae R-7 group and Ricenellaceae RC9 gut group were stabilized by SCFPb-2x. Hence, SCFP attenuated the negative effect of SARA on the co-occurrence patterns in the rumen fluid microbiota.

285 Effects of Encapsulated Calcium-ammonium Nitrate on Greenhouse Gas Emissions from Manure of Beef Steers Grazing a Mature Mixed-winter Forage

A 30-d experiment was conducted to evaluate daily and cumulative gas fluxes of N2O, CH4, and CO2 produced by manure from Angus-crossbred steers grazing mature mixed-winter forage pastures [wheat, triticale, and rye (Triticum aestivum, Triticosecale rimpaui, and Secale cereal, respectively) and receiving N supplementation from two different sources. Steers received the following treatments: 1) mature mixed-winter pasture + ground corn (NCTRL), 2) NCTRL + 328 mg/kg of BW encapsulated calcium-ammonium nitrate (NIT) and 3) NCTRL + 124 mg/kg of BW urea (CTRL). All ground corn was supplemented at 0.3% BW. Treatments NIT and CTRL were isonitrogenous. Feces were collected and composited (1 kg as-is) within treatment, within block (3 blocks; 4 steers/treatment/block; 3 fecal composites/treatment). Gas samples were collected from static chambers previously installed in an area excluded from grazing. After 3 d, composites were deposited on the soil surface inside the chamber. Four subsamples were taken per deployment time per chamber, separated by 10-min intervals (t0, t10, t20 and t30) and injected into an evacuated 125-mL serum vial. Gas samples were collected every other day between 0900 and 1100 h and analyzed using a gas chromatograph. Data were analyzed as a randomized complete block design, with chamber as the experimental unit, using the MIXED procedure of SAS. No treatment × day interaction (P ≥ 0.145), nor treatment (P ≥ 0.622) effect were observed on daily-flux data for N2O, CH4, and CO2; however, a day effect was observed (P ≤ 0.001) where all gases peaked on d 2 post-manure application on the soil. Cumulative emissions were not different among treatments for N2O, CH4, and CO2 (P ≥ 0.663). Although it was expected for encapsulated calcium-ammonium nitrate to increase N2O emissions, such effect was not observed. Therefore, it appears that encapsulated calcium-ammonium nitrate does not affect manure greenhouse gas emissions.

Evaluation of Hammermill Tip Speed, Air Assist and Screen Hole Diameter on Ground Corn Characteristics

This study was performed to evaluate hammermill tip speed, assistive airflow, and screen hole diameter on hammermill throughput and characteristics of ground corn. Corn was ground using two Andritz hammermills measuring 1 m in diameter each equipped with 72 hammers and 300 HP motors. Treatments were arranged in a 3 × 3 × 3 factorial design with three tip speeds (3774, 4975, and 6176 m/min), three screen hole diameters (2.3, 3.9, and 6.3 mm), and three air flow rates (1062, 1416, and 1770 fan revolutions per minute). Corn was ground on three separate days to create three replications and treatments were randomized within day. Samples were collected and analyzed for moisture, particle size, and flowability characteristics. There was a 3-way interaction (p = 0.029) for standard deviation (Sgw). There was a screen hole diameter × hammer tip speed interaction (p < 0.001) for geometric mean particle size dgw (p < 0.001) and composite flow index (CFI) (p < 0.001). When tip speed increased from 3774 to 6176 m/min, the rate of decrease in dgw was greater as screen hole diameter increased from 2.3 to 6.3 mm. For CFI, increasing tip speed decreased the CFI of ground corn when ground using the 3.9 and 6.3 mm screen. However, when grinding corn using the 2.3 mm screen, there was no evidence of difference in CFI when increasing tip speed. In conclusion, the air flow rate did not influence dgw of corn, but hammer tip speed and screen size were altered and achieved a range of dgw from 304 to 617 µm.

The Effects of Using Pineapple Stem Starch as an Alternative Starch Source and Ageing Period on Meat Quality, Texture Profile, Ribonucleotide Content, and Fatty Acid Composition of Longissimus Thoracis of Fattening Dairy Steers

The effects of different starch sources (ground corn (CO), ground cassava (CA) and pineapple stem starch (PI)) and ageing period (14 and 21 days) on meat characteristics of Holstein steers were investigated. Starch sources had no effect on meat characteristics, while meat aged for 14 days had less thawing loss than that aged for 21 days. Meat from steers fed PI had higher levels of inosine monophosphate (IMP) than the others (p < 0.05). With increasing duration of ageing, the content of IMP and guanosine monophosphate in the meat decreased, while the content of hypoxanthine increased (p < 0.05). Meat from steers fed CO had the highest oleic acid but the lowest erucic acid (p < 0.05) in contrast to meat from steers fed PI, which had the lowest oleic acid but the highest erucic acid. Steers fed CO appeared to produce healthier meat as this was positively associated with monounsaturated fatty acid content. Meat from steers fed PI had higher levels of IMP, which may be associated with good taste.

Effects of Grinding Corn with Different Moisture Content on Subsequent Particle Size and Flowability

The objective of this study was to determine the effects of whole-corn moisture and hammermill screen size on subsequent ground corn moisture, particle size and flowability. Treatments were arranged as a 2 × 2 factorial design with two moisture concentrations (14.5 and 16.7%), each ground using 2 hammermill screen sizes (3 mm and 6 mm). Corn was ground using a lab-scale 1.5 HP Bliss Hammermill at three separate timepoints to create three replications per treatment. Ground corn flowability was calculated using angle of repose (AOR), percent compressibility, and critical orifice diameter (COD) measurements to determine the composite flow index (CFI). There was no evidence for a screen size × corn moisture interaction for ground corn moisture content (MC), particle size, standard deviation, or flowability metrics. Grinding corn using a 3 mm screen resulted in decreased (p < 0.041) moisture content compared to corn ground using the 6 mm screen. There was a decrease (p < 0.031) in particle size from the 6 mm screen to the 3 mm, but no evidence of difference was observed for the standard deviation. There was a decrease (p < 0.030) in percent compressibility as screen size increased from 3 mm to 6 mm. Angle of repose tended to decrease (p < 0.056) when corn was ground using a 6 mm screen compared to a 3 mm screen. For the main effects of MC, 16.7% moisture corn had increased (p < 0.001) ground corn MC compared to 14.5%. The 14.5% moisture corn resulted in decreased (p < 0.050) particle size and an increased standard deviation compared to the 16.7% moisture corn. The increased MC of corn increased (p < 0.038) CFI and tended to decrease (p < 0.050) AOR and COD. In conclusion, decreasing hammermill screen size increased moisture loss by 0.55%, decreased corn particle size by 126 µm and resulted in poorer flowability as measured by percent compressibility and AOR. The higher moisture corn increased subsequent particle size by 89 µm and had improved flowability as measured by CFI.