Nutritional value, productive performance, and economic efficiency response to the degree of steam-flaked yellow corn in growing rabbits.

The performance of a corn steam flaker was evaluated to improve steam-flaked corn (SFC) quality and investigate its feeding effects on nutritional value, productive performance, digestibility coefficients, and economic efficiency of growing rabbits. The flaker performance was studied as a function of change in steaming time, steam chest temperature and roll gap. Performance evaluation of the flaker was carried out in terms of flake thickness (FT), flake density (FD) and processing index (PI) as well as rabbit feeding trials. Experimental results clarified that values of FT, FD and PI are in the optimal limits under conditions of 118°C steam chest temperature, 40 min steaming time and 0.80 mm roll gap. Steam flaking is an acceptable process for rabbit feeds as SFC with optimal FD of between 0.36 and 0.39 kg/L corresponding to a PI of between 50.14% and 54.32% significantly improve the nutritional value of SFC compared with whole corn grain by 1.31%, 1.26% and 160.75% respectively. Also, SFC severely decreased the total count of harmful bacteria, fungi count and mortality rate compared to whole corn grain. Rabbits fed SFC processed to the density of 0.36 kg/L of the diet had better body weight gain, feed conversion ratio, organic matter digestibility, net revenue and economic efficiency of 9.29%, 8.89%, 4.65%, 15.62% and 15.43% compared with rabbit fed whole yellow corn grain respectively. In conclusion, it is convenient to entirely substitute whole corn grain with SFC to be utilised in rabbits' diets where achieved the best feeding effects results.

Effects of processing methods (rolling vs. pelleting vs. steam-flaking) of cool-season adapted oats on dairy cattle production performance and metabolic characteristics compared with barley.

Several processing techniques can be used to slow the degradation rate in the rumen and thus provide more bypass crude protein (CP) and starch to the small intestine. The aim of this study was to evaluate the effects of processing methods on cool-season adapted oat grain compared with dry-rolled barley grain, when fed as total mixed ration (TMR) for lactating dairy cows. Eight lactating Holstein cows were used in a replicated 4 × 4 Latin square design with 21-d periods and fed TMR with 1 of 4 treatments: dry-rolled oats, steam-flaked oats, pelleted oats, or dry-rolled barley. Dry matter intake (DMI) ranged from 28.19 to 31.61 kg/d and was lower for rolled oats compared with pelleted oats. Despite the nutrient intake being higher for cows fed pelleted oats, those fed rolled oats had the highest milk production and milk fat percentage (49.23 kg/d and 4%, respectively). Ruminal fermentation characteristics were similar across treatments, with only significant differences in concentrations of acetate (lowest for pelleted oats) and total short-chain fatty acids (highest value for rolled barley) and a lower pH for flaked oats at the 9-h and 12-h points. Dietary treatments did not affect total-tract digestibility of dry matter, organic matter, or CP; digestibility of starch was the lowest for rolled barley (89.04%). Measured blood metabolites, urea, glucose, and ß-hydroxybutyrate, were not affected by dietary treatment. Purine derivatives and microbial N supply were also unaffected by dietary treatments. Cows fed flaked oat-based TMR showed the lowest N excretion in milk; however, the lack of difference between diets with regard to urinary N and fecal N excretion resulted in no significant changes in N balance between diets. Therefore, rolled oats allow cows to have higher milk production with lower DMI compared with all other treatments in this study.

Performance, nutritional behavior, and metabolic responses of calves supplemented with forage depend on starch fermentability.

This study evaluated the interactive effects of forage provision on performance, nutritional behavior, apparent digestibility, rumen fermentation, and blood metabolites of dairy calves when corn grains with different fermentability were used. Sixty 3-d-old Holstein calves were randomly assigned to 1 of 4 treatments in a 2 × 2 factorial arrangement. Dietary treatments were (1) steam-flaked (SF) corn without alfalfa hay (AH) supplementation (SF-NO), (2) SF corn with AH supplementation (SF-AH), (3) cracked (CR) corn without AH supplementation (CR-NO), and (4) CR corn with AH supplementation (CR-AH). All calves received the same amount of pasteurized whole milk and weaned on d 56 of the experiment; the study was terminated on d 70. Steam-flaked corn contained higher amounts of gelatinized starch in comparison with cracked corn (44.1 vs. 12.5% of total starch, respectively). Starter intake was not affected by corn processing methods or AH provision during the pre- or postweaning periods. However, we noted an interaction between corn processing methods and forage supplementation for starter intake during d 31 to 50 of the experiment, where calves fed on SF-AH starter had greater starter intake than those fed SF-NO starter, but the starter intake was not different between CR-NO and CR-AH fed calves. Furthermore, AH increased average daily gain (ADG) of calves fed an SF-based diet but not in calves fed a CR-based diet during the preweaning and overall periods. Interaction between forage provision and time was significant for ADG and feed efficiency, as calves supplemented with forage had higher ADG (0.982 vs. 0.592, respectively) and feed efficiency compared with forage unsupplemented calves at the weaning week. Forage supplementation resulted in more stable ruminal condition compared with nonforage-fed calves, as evidenced by higher ruminal pH (5.71 vs. 5.29, respectively) at postweaning and lower non-nutritive oral behavior around weaning time (55 vs. 70.5 min, respectively). The concentration of blood ß-hydroxybutyrate was also greater in calves supplemented with forage than in unsupplemented calves. Results of the present study indicated that performance response and skeletal growth were the same between 2 corn processing methods. Forage provision improved ADG of calves fed the SF-based diet, but not the CR-based diet throughout the study.

Interaction of Sweet Bran inclusion and corn processing method in beef finishing diets.

The study objective was to determine the effects of corn processing method and Sweet Bran (Cargill, Blair, NE) inclusion in beef finishing diets on performance and carcass characteristics. Four hundred and eighty crossbred yearling steers (363 ±â€…15 kg) were assigned to a 2 × 3 factorial arrangement of treatments, consisting of two corn processing methods, steam-flaked corn (SFC) or a high-moisture corn: dry-rolled corn blend (HMC: DRC), and three inclusions of Sweet Bran (0%, 20%, or 40% of diet dry matter). Data were analyzed using the MIXED procedure of SAS as a generalized block design with pen as the experimental unit and block as a fixed effect. Dry matter intake increased linearly as Sweet Bran increased in the diet, regardless of corn processing method (P < 0.01). A corn processing × Sweet Bran interaction (P < 0.01) was observed for feed efficiency (G:F), average daily gain (ADG), and hot carcass weight (HCW). The G:F of steers fed SFC did not change with increasing Sweet Bran concentrations (P = 0.19) and the G:F of SFC-fed steers was 12.4% greater than those fed HMC:DRC without Sweet Bran, but was only 5.3% greater when Sweet Bran was included at 40% (P = 0.04). The ADG of steers increased linearly with increasing concentration of Sweet Bran in both SFC and HMC:DRC-based diets. However, the interaction occurred (P < 0.01) because ADG increased at a greater rate in HMC:DRC-based diets (1.93 to 2.21 kg/d for 0% and 40% Sweet Bran, respectively) compared to SFC-based diets (2.18 to 2.27 kg/d for 0% and 40% Sweet Bran, respectively;). Accordingly, while the ADG of steers fed SFC was 13% greater than steers fed HMC:DRC without Sweet Bran (P < 0.01), there was no difference in ADG due to corn processing method at 40% Sweet Bran (P = 0.30). In SFC-based diets, HCW tended to increase from 446 to 455 kg as Sweet Bran increased (P = 0.06). In HMC: DRC-based diets, HCW linearly increased from 421 to 449 kg (P < 0.01), resulting in similar HCW at 40% Sweet Bran (P = 0.28). These data suggest HMC:DRC-based diets are more competitive with SFC-based diets due to similar gains and more similar feed efficiencies when Sweet Bran is fed.

Effects of high-amylase corn on performance and carcass quality of finishing beef heifers.

Developed initially for use in fuel ethanol production, Enogen Feed Corn (EFC; Syngenta Crop Protection) is genetically modified to express high concentrations of α-amylase in the corn kernel. Experiments were conducted to evaluate processing characteristics of EFC, in vitro digestion, and effects on feedlot performance, carcass characteristics, and liver abscess incidence. Experiment 1 used a randomized complete block design (3 × 3 × 5 factorial) to evaluate starch availability, in situ dry matter disappearance (ISDMD), in vitro gas production (IVGP), and volatile fatty acid (VFA) profiles of in vitro cultures. Grains (EFC or mill-run control [CON]) were flaked to a density of 360 g/L, and mixtures with 0%, 25%, 50%, 75%, or 100% EFC were prepared. Grains were tempered with added moisture (0%, 3%, or 6%) prior to steam conditioning for 15, 30, or 45 min. No two- or three-way interactions were observed. Adding moisture improved starch availability (linear; P < 0.01), and tended to improve ISDMD (linear, P = 0.06). Steam conditioning for 30 min improved starch availability, IVGP, and production of acetate, propionate, butyrate, valerate, and total VFA (P < 0.01) compared with conditioning for 15 or 45 min. Starch availability, ISDMD, IVGP, acetate, propionate, valerate, and total VFA production increased with an increasing proportion of EFC (linear, P < 0.01). Experiment 2 used 700 beef heifers (394 ± 8.5 kg initial body weight [BW]) fed finishing diets with steam-flaked corn as CON or EFC for 136 d. Targeting similar starch availabilities, grains were processed to 360 g/L (CON) and 390 g/L for CON and EFC, respectively. Heifers were blocked by BW, stratified, and then randomly assigned to 28 dirt-surfaced pens (25 animals per pen). Dry matter intakes were similar between treatments (P = 0.78), but cattle fed EFC had greater average daily gain (P < 0.01), improving feed efficiency by 5% (P < 0.01). Hot carcass weight was 6 kg greater for EFC cattle (P <0.01) than CON. No differences were observed for longissimus muscle area (P = 0.89), 12th-rib fat thickness (P = 0.21), or USDA yield grade (P = 0.13). Cattle fed CON had greater marbling scores than EFC (P = 0.04), but this did not affect the USDA quality grade (P > 0.33). Cattle fed EFC had 23% fewer abscessed livers than CON (P = 0.03). High-amylase corn may be used to improve microbial digestion, mill-throughput, and cattle performance, and it may mitigate liver abscesses.

Variance of Zein Protein and Starch Granule Morphology between Corn and Steam Flaked Products Determined Starch Ruminal Degradability Through Altering Starch Hydrolyzing Bacteria Attachment.

The current study investigated differences of γ-zein protein contents and starch granule characteristics between raw and steam flaked corns and their influences on ruminal starch hydrolyzing bacteria (SHB) attached to corn grain. Two types of raw (Corn1 and Corn2) and their steam-flaked products (SFCorn1 and SFCorn2) were applied to explore physiochemical structures and SHB attachment. SDS-PAGE was conducted to detect γ-zein protein patterns, scanning electron microscope, and small angle X-ray scattering were performed to obtain starch granule morphology, while crystallinity, DQ starch, and DAPI staining were applied to quantify SHB. The steam flaking process destroyed γ-zein proteins and gelatinized starch granules. The median particle size of Corn1 and Corn2 starch granules increased from 17.8 and 18.0 µm to 30.8 and 26.0 µm, but crystallinity decreased from 22.0 and 25.0% to 9.9 and 16.9%, respectively. The percentage of SHB attached to Corn1 residues decreased (p = 0.01) after 4 h incubation, but SHB attached to SFCorn1 residues increased (p = 0.03) after 12 h incubation. Thus, the differences of γ-zein proteins and starch granule physiochemical structures between raw and steam flaked corn played an important role in improving the rate and extent of starch ruminal degradation through altering the process of SHB attached to corn.

Alteration of biomacromolecule in corn by steam flaking in relation to biodegradation kinetics in ruminant, revealed with vibrational molecular spectroscopy.

Large scale of steam flaked corn has been used in dairy ration to maintain high milk production level. This study aimed to determine effects of steam flaking on processing-induced intrinsic molecular structure changes that were associated with rumen degradation kinetics and nutrients supply. The advanced vibrational molecular spectroscopy was applied to reveal the processing-induced intrinsic structure changes on a molecular basis. The rumen degradation kinetics and nutrient supply were determined using in situ approach in ruminant livestock system. Raw corn grain (RC) and steam flaked corn grain (SFC) were obtained from two different processing plants. The results showed that (1) Compared to RC, SFC had greater truly digestible non-fiber carbohydrate [tdNFC: 86.8 versus 78.0% dry matter (DM)], but lower truly digestible crude protein [tdCP: 7.7 versus 9.0% DM]. (2) The steam flaking increased (P<0.01) rumen degradable DM (RDDM) and starch (RDSt), but decreased (P<0.01) rumen degradable protein (RDP). (3) Molecular absorbance intensities of most carbohydrate biopolymers were greater in SFC (P<0.01), but protein amides associated molecular spectral intensities were lower (P<0.01) in SFC. (4). The molecular structure and nutrient interactive study showed that carbohydrate spectral intensities were positively (P<0.10) associated with RDDM and RDSt and protein amide spectral intensities were positively (P<0.10) associated with RDP. This results indicated that the steam flaking induced molecular structure changes had an interactive relationship with rumen degradation kinetics.