Economic Research on Ethanol Feed-Use Coproducts: A Review, Synthesis, and Path Forward

During the mid-2000s to the early 2010s, the domestic ethanol industry witnessed substantial growth, with ethanol coproducts emerging as vital elements for plant profitability and livestock feeding. Initially serving as supplementary revenue streams, coproducts from ethanol production have evolved into diverse value-added offerings, bolstering revenue streams, and sustaining profit margins. This study reviews existing economic research on ethanol coproducts, detailing methodologies, product focus, and research locations. Initially gathering 972 articles from 9 databases, 110 articles were synthesized. We find that most studies primarily examined the growth and future of the ethanol industry with a limited focus on specific coproducts. Feed-use distillers' grains, especially dried distillers' grains, were the most widely published while newer coproducts like pelletized, de-oiled, and high-protein distillers' grains were relatively understudied. Non-feed-use products were notably overlooked, highlighting the need for exploration beyond conventional applications. The evolving market landscape for ethanol co-products has surpassed published academic understanding of the economic tradeoffs necessitating further research into product dynamics, pricing, marketing, market structures, and regulatory frameworks. This highlights and underscores the importance of investigating value-added grains across diverse commodities and geographic contexts to inform strategic decision-making and policy formulation.

Animal performance and meat quality characteristics from feedlot-finished steers fed increasing levels of wet distillers grain

One hundred forty-four steers were group-housed in 24 pens that were randomly assigned to one of four dietary treatments defined by the proportion of wet distiller grain plus solubles (WDGS; 0, 15, 30, or 45%) and fed for 84 d pre-slaughter. Animal performance was evaluated using the pen as the experimental unit. Whereas for carcass and meat quality characteristics, meat oxidative stability, and the consumer sensory quality of longissimus thoracis muscle one animal from each pen was randomly selected and used as the experimental unit. No differences (P > 0.05) were observed for subcutaneous fat thickness, rib eye area, marbling score or pH, color parameters, proximate composition, sarcomere length, Warner Bratzler shear force, and cooking loss. Feeding WDGS linearly increased total PUFA (P = 0.05), C18:2 n-6 (P = 0.004) proportions, and n-6/n-3 ratio (P < 0.01) but reduced C16:1 to C18:0 ratio (P < 0.01). Lipid oxidation was greater in beef from steers fed 30% and 45% WDGS (P = 0.05). Dietary WDGS linearly improved (P < 0.05) flavor and overall linking score in the consumer sensory panel.

Feeding hempseed cake alters the bovine gut, respiratory and reproductive microbiota

A growing number of studies have investigated the feasibility of utilizing hemp by-products as livestock feedstuffs; however, their impact on livestock microbiomes remains unexplored. Here, we evaluated the effects of feeding hempseed cake on the gastrointestinal, respiratory, and reproductive microbiota in beef heifers. Angus-crossbred heifers (19-months old, initial body weight = 494 ± 10 kg [SE]) were fed a corn-based finishing diet containing 20% hempseed cake as a substitute for 20% corn dried distillers' grains with solubles (DM basis; Control; n = 16/group) for 111 days until slaughter. Ruminal fluid and deep nasopharyngeal swabs (days 0, 7, 42, 70 and 98), and vaginal and uterine swabs (at slaughter) were collected, and the microbiota assessed using 16S rRNA gene sequencing. Diet affected the community structure of the ruminal (d 7-98; 0.06 ≤ R² ≤ 0.12; P < 0.05), nasopharyngeal (d 98; R² = 0.18; P < 0.001), and vaginal (R² = 0.06; P < 0.01) microbiota. Heifers fed hempseed cake had increased microbial diversity in the rumen, reduced microbial richness in the vagina, and greater microbial diversity and richness in the uterus. In addition to the distinct microbial communities in the rumen, nasopharynx, vagina and uterus, we identified 28 core taxa that were shared (≥ 60% of all samples) across these sampling locations. Feeding hempseed cake appeared to alter the bovine gut, respiratory and reproductive microbiota. Our results suggest that future research aiming to evaluate the use of hemp by-products in livestock diet should consider their impact on animal microbiome and microbiome mediated animal health and reproductive efficiency. Our findings also highlight the need for research evaluating the impact of hemp-associated food and personal care products on the human microbiome.

Pooled analysis on the effects of inclusion, moisture, and oil removal from distillers grains on cattle performance and economic returns in diets with different corn processing

A synthesis of data including over 9,300 head of cattle and over 980 pen means was conducted to evaluate the effect of corn processing method, distillers grains type, oil removal from distillers, and dietary distillers concentration on cattle performance and total feeding costs under different historical price scenarios. The corn processing method was either steam-flaked corn, high-moisture or dry-rolled corn or a blend of the latter two and their effects on performance with and without distillers grains. Wet, modified, and dry distillers were analyzed as either full fat or de-oiled products in diets at various dietary concentrations with either corn type to determine cattle performance. Performance estimates were used to determine the inclusion level that minimized total finishing costs ($/head) for each diet given various assumptions on corn price, corn-to-distillers price ratio, supplemental protein cost, and steam flake processing cost. Feeding distillers grains in steam-flaked or high-moisture and dry-rolled corn diets resulted in improved feed conversion and reduced cattle feeding costs, including lower supplemental protein costs and lower total feeding costs compared with a diet without distillers. However, feeding diets with steam-flaked corn improved feed conversion regardless of distillers type or level of inclusion. Feeding full fat distillers improved feed conversion relative to de-oiled distillers. Cattle fed de-oiled distillers were more efficient than those fed diets containing no distillers grains. At all corn price and corn-to-distillers price ratios examined, feeding some level of distillers of any type produced a lower total feeding costs relative to a diet without distillers. Different robustness tests were conducted to determine the impact of varying steam flake corn processing costs and the cost of supplemental protein on the optimal level of distillers inclusion level. The break-even cost a producer could pay for steam-flaking corn varied but was significantly higher when corn price was high. Feeding distillers grains in steam-flaked or high-moisture and dry-rolled corn diets resulted in improved feed efficiency, reduced cattle feeding costs, including replacement of other supplemental protein and associated costs compared to a diet without distillers grains.

Meat Quality and Muscle Tissue Proteome of Crossbred Bulls Finished under Feedlot Using Wet Distiller Grains By-Product

Wet distiller grains (WDG) are a corn by-product rich in protein and fiber that can be used in feedlot diets. This study evaluated F1 Angus-Nellore bulls fed on a control diet vs. WDG (n = 25/treatment). After a period of 129 days on these feeds, the animals were slaughtered and Longissimus thoracis samples were collected for both a meat quality evaluation and gel-based proteomic analyses. A greater ribeye area (99.47 cm²) and higher carcass weight (333.6 kg) (p < 0.05) were observed in the WDG-finished cattle compared to the control (80.7 cm²; 306.3 kg). Furthermore, there were differences (p < 0.05) in the intramuscular fat between the WDG and control animals (IMF = 2.77 vs. 4.19%), which led to a significant decrease (p < 0.05) in saturated fatty acids (FA). However, no differences (p > 0.10) were observed in terms of tenderness, evaluated using Warner–Bratzler shear force (WBSF). The proteomic and bioinformatic analyses revealed substantial changes in the biological processes, molecular functions, and cellular components of the WDG-finished cattle compared to the control. Proteins related to a myriad of interconnected pathways, such as contractile and structural pathways, energy metabolism, oxidative stress and cell redox homeostasis, and transport and signaling. In this experiment, the use of WDG supplementation influenced the protein expression of several proteins, some of which are known biomarkers of beef quality (tenderness and color), as well as the protein–protein interactions that can act as the origins of increases in muscle growth and reductions in IMF deposition. However, despite the effects on the proteome, the tenderness, evaluated by WBSF, and fatty acid profile were not compromised by WDG supplementation.

Net Conversion of Human-Edible Vitamins and Minerals in the U.S. Southern Great Plains Beef Production System

Beef is a good source of several vitamins and minerals but data on the net contribution to the human diet is lacking. The objective was to quantify the net nutrient contribution of the beef supply chain to provide vitamins and minerals to the human diet. Beef cattle production parameters for the beef supply chain were as described by Baber et al., 2018 with the red and organ meat yield from each production segment estimated using literature values of serially-harvested beef cattle. Nutrient concentration of feeds was acquired from feed composition tables in nutrient requirement texts, and the nutrient concentration of beef and organ meats was based on 2018 USDA Food and Nutrient Database for Dietary Studies. The nutrient absorption coefficients of feeds, red meat, and organs were acquired from the literature. The human-edible conversion ratio was >1.0 for phosphorus when only red meat yield was considered indicating that the beef supply chain produced more human-edible phosphorus than it consumed. When organ meats were included, riboflavin, niacin, choline, and phosphorus had conversion ratios >1.0. After adjusting for the absorption of nutrients, the beef supply chain was a net contributor of niacin and phosphorus in the human diet when accounting for red meat yield only, but when including organ meats, iron, riboflavin, and choline also had conversion ratios >1.0. The maximum proportion of corn in the corn grain plus distillers’ grains component of the feedlot diets for the absorbable conversion ratio to be ≥1 ranged from 8.34 to 100.00% when only red meat yield was considered and from 32.02 to 100.00% when red and organ meats were considered. In conclusion, the current beef production system in the Southern Great Plains produces more human-absorbable iron, phosphorus, riboflavin, niacin, and choline to the human diet than is consumed in the beef supply chain.

Assessment of corn wet distillers grains fed to crossbred bulls on feeding behavior, rumen morphology, liver abscesses and blood parameters

Corn ethanol production has been growing in Brazil in the last ten years, generating by-products to feedlot diets. This study evaluates the effects of the inclusion of low-fat corn wet distillers grains (LF-WDG) on feeding behavior, ruminal health, liver abscesses and blood parameters of F1 Angus-Nellore bulls feedlot finished. Our hypothesis is that evaluation of data from feeding behavior, rumen and liver health would help to explain animal performance. In this trail, one-hundred animals were fed for 129 days with diets containing amounts of 0 (control), 15, 30 and 45% of LF-WDG replacing corn grain and soybean meal. Evaluations of fluctuation of dry matter intake (DMI) were carried out. Additionally, feeding behavior data were assessed by monitoring (24-h period) the feeding, rumination, time spent eating (TSE), and time expended on other activities (resting and number of meals per day). Blood variables such as pH, bicarbonate, total CO2 content, and base excess in extracellular fluid (Beecf) were determined. After slaughter, rumen epithelium was classified according to the incidence of lesions (rumenitis) and abnormalities (papillae clumped), and samples were collected for morphology and histology evaluations. Moreover, livers were scored for severity of abscesses as follow: as unabscessed (0), one or two small abscesses (A−), two to four small active abscesses (A) or one or more large, active abscesses (A+). The DMI (kg/day) differed (P = 0.03) among treatments and there is a tendency of 15 and 30 LF-WDG (% DM) had lower %DMI fluctuation compared to 0 or 45%. The TSE increased linearly (P < 0.01) as the amounts of inclusion of LF-WDG increased. Moreover, neutral detergent fiber (NDF) intake, NDF consumption rate and NDF rumination efficiency increased linearly (P < 0.01) in response to LF-WDG feeding. The incidence of rumenitis tended (P = 0.08) to be greater at 45% LF-WDG, while keratin thickness decreased linearly in bulls fed LF-WDG (P < 0.01). The severity of liver abscesses (score A+) increased linearly (P = 0.02). Regarding blood parameters, only Beecf decreased linearly (P < 0.01) in response to LF-WDG feeding. Therefore, the hypothesis of the current study was confirmed. We previous reported that F1 Angus-Nellore bulls fed LF-WDG show greater weight gain (1.94 ± 0.09 kg/day) and final body weight (620 ± 18.8 kg) when compare to control (1.8 ± 0.09 kg/day and 602 ± 18.8 kg, respectively). Here, we conclude that inclusion of 15 to 30% LF-WDG in feedlot diets improved feeding behavior without impairing ruminal health and blood parameters, driving performance and weigh gain of crossbred bulls. However, bulls fed 45% LF-WDG had greater severity of liver abscesses.

Dried distiller's grains for feedlot Nellore cattle fed non-forage-based diets

This study aimed to evaluate intake, animal performance and carcass traits with the inclusion of corn dried distiller grains (DDGs) replacing cornmeal (Zea mays L.) in non-forage-based diets for finishing feedlot Nellore cattle. Sixty-four uncastrated Nellore cattle weighing 267.22 ± 20.4 kg and 18 ± 3 months old were distributed in 16 pens. Experimental diets were based on cornmeal, cottonseed cake, a mineral mixture and increased levels of DDG replacing cornmeal (0, 10, 20 and 30% on a dry matter basis). The study lasted 135 days, and the intake of nutrients and body weight gain were monitored. At the end of the study, the animals were slaughtered to measure their carcass traits. During the first 34 days of the study, the DDG levels linearly increased dry matter intake and intake of all nutrients. In other phases of the feedlot, the DDG levels did not have any effect on DMI or ADG but caused a quadratic effect on hot carcass weight. Thus, DDG can replace cornmeal in non-forage diets fed to feedlot Nellore cattle without any negative effect on intake or animal performance.

Impacts of including Sweet Bran and wet distillers grains with solubles alone or in combination in finishing cattle diets on physically effective fiber concentrations and rumen buffering characteristics of feedlot cattle

This study evaluated the effects of Sweet Bran (SB) and wet distillers grains with solubles (WDGS) in the diet alone or in combination on physically effective neutral detergent fiber (peNDF), ruminal pH, and rumination behavior of finishing beef cattle. For this study, 455 steers (373 ± 15.5 kg) were allocated to 48 pens in a randomized complete block design. Treatments (n = 12 pens per treatment) were one of four steam-flaked corn-based diets containing no corn-milling products (CON), 20% WDGS (WDGS20), 20% SB (SB20), or 20% SB and 10% WDGS (COMBO). Within each pen, two steers were randomly selected to receive an indwelling ruminal pH bolus to quantify ruminal pH and a 3-axis accelerometer tag to measure rumination for the first 92 d of the study. Diet samples were collected weekly to determine particle size, neutral detergent fiber (NDF) concentration, and peNDF. Physically effective NDF was calculated using both the proportion of particles > 4.0 mm (peNDF_4.0) and the proportion of particles > 8.0 mm (peNDF_8.0). The percentage of particles > 4.0 mm was greatest (P < 0.01) for CON, intermediate for SB20, and least for WDGS20 and COMBO. Both NDF (P < 0.01) and peNDF_4.0 (P < 0.01) were greatest for COMBO, intermediate for WDGS20 and SB20, and least for CON. The percentage of particles > 8.0 was greatest (P < 0.01) for CON, intermediate for WDGS20 and SB20, and least for COMBO, but peNDF_8.0 did not differ (P = 0.40). A diet × day interaction (P < 0.01) was observed for daily rumination minutes per kg of DMI, NDF, peNDF_4.0, and peNDF_8.0. A diet × hour interaction (P < 0.01) was observed where CON cattle spent less time ruminating at 0800 and 1000 h in a 24 h period. Daily ruminal pH was greatest (P < 0.01) for COMBO, intermediate for SB20 and WDGS20, and least for CON. A diet × hour interaction (P < 0.01) was also observed for circadian ruminal pH, where pH was least for CON from 0800 to 1800 h. Relationships between peNDF, rumination behavior, and ruminal pH observed in this study suggest that SB and WDGS similarly enhance rumen buffering capacity when steam-flaked corn is replaced in the diet.

Interaction of replacing corn silage with soyhulls as a roughage source with or without 3% added wheat straw in the diet: impacts on intake, digestibility and ruminal fermentation in steers fed high-concentrate diets

Six ruminally cannulated steers [475.0 ± 49.6 kg initial body weight (BW)] were used in a 6 × 3 incomplete Latin square design (6 treatments and 3 periods), to evaluate the impacts replacing of corn silage with pelleted soyhulls as roughage in high-concentrate finishing diets containing 30% modified distillers grains with solubles. Treatments were based on increasing dietary inclusion of soyhulls and consisted of: 1) Control (0), roughage supplied by dietary inclusion of 20% corn silage [dry matter (DM) basis], 2) 50% replacement of corn silage with soyhulls (50), 3) 100% replacement of corn silage with soyhulls (100), and the same three treatments repeated with 3% added wheat straw (DM basis) replacing corn in the diet (0S, 50S, and 100S, respectively). Absolute dry matter intake (DMI; kg/d basis) tended to decrease both linearly and quadratically (P ≤ 0.09) and proportional DMI (% of BW) decreased linearly (P = 0.04) with increasing soyhull inclusion but was not affected by the addition of straw in the diet (P = 0.68). Total tract digestibility of organic matter and crude protein were not affected by soyhull inclusion or added straw (P ≥ 0.32). Ruminal pH did not differ (P = 0.65) with increasing soyhull inclusion but increased with the addition of straw (P &lt; 0.01; 5.9 versus 6.1 for no straw and straw, respectively). Molar proportions of acetate and butyrate decreased while propionate increased with increased soyhull inclusion (P ≤ 0.03; linearly and quadratically respectively). Ruminal fluid kinetics were unaffected be either rate of replacement of corn silage with soyhulls or wheat straw inclusion (P ≥ 0.13). Decreases in DMI observed in this study would likely decrease finishing cattle performance and underscores the need for additional research before recommending this practice to cattle feeders.

Impacts of added roughage on growth performance, digestibility, ruminal fermentation, and ruminal pH of feedlot steers fed wheat-based feedlot diets containing 30% modified distillers grains with solubles

Two experiments were conducted to evaluate the inclusion rate roughage in wheat-based diets containing modified distillers grains with solubles (MDGS) on feedlot performance (Feedlot Experiment), as well as digestibility, ruminal pH, and ruminal fermentation characteristics (Digestibility Experiment). The feedlot experiment utilized 72 Angus steers (392 ± 46.3 kg initial body weight) which were randomly assigned to 1 of 12 pens, 3 pens per treatment, to evaluate feedlot performance and carcass characteristics. Dietary treatments were 1) control; 10% roughage, 2) 12% roughage, 3) 14% roughage, and 4) 16% roughage. The digestibility experiment used four ruminally and duodenally cannulated steers (393 ± 33.0 kg) in a 4 × 4 Latin Square with either 10%, 12%, 14%, or 16% roughage as in the feedlot experiment. However, dietary roughage source was different between these two experiments and included a combination of grass hay and wheat straw (Feedlot Experiment), and corn silage (Digestibility Experiment). All data were analyzed with the Mixed Procedures of SAS. Feed intake was recorded, with duodenal and fecal output calculated using chromic oxide. Ruminal pH and fermentation were assessed. Growth performance and most carcass characteristics were not affected by increasing roughage (P ≥ 0.11). Marbling tended to decrease linearly (P = 0.10) with increasing roughage inclusion. Increasing dietary roughage content had no effect on organic matter intake (P = 0.60) in the digestibility experiment. Intake, duodenal flow, and digestibility of neutral detergent fiber and acid detergent fiber were not affected by treatment (P ≥ 0.16). Ruminal pH increased linearly (P < 0.01) as rate of roughage inclusion increased. Ruminal concentrations of acetate and butyrate increased, and propionate decreased in a linear fashion (P < 0.01) thereby increasing (P < 0.01) acetate and butyrate to propionate ratio with increasing dietary roughage. Our data indicate that increasing roughage inclusion in wheat-based diets including 30% MDGS increased ruminal pH and shifted ruminal fermentation patterns. Additionally, increasing roughage inclusion did not affect feedlot performance in steers fed wheat at 36% to 42% of dietary dry matter in combination with 30% MDGS.

Effect of Aging and Retail Display Conditions on the Color and Oxidant/Antioxidant Status of Beef from Steers Finished with DG-Supplemented Diets

The aim of this work was to study the effect of finishing diets including distiller grains (DG) on color and oxidative stability of beef after being exposed to aerobic retail display conditions, with or without previous aging. For this purpose, beef samples from animals fed with finishing diets including 0%, 15%, 30%, and 45% DG (on a dry matter basis), which had been exposed to aerobic retail display conditions, with or without previous aging under vacuum packaging, were evaluated. The content of γ-tocopherol, β-carotene, and lutein in diet samples increased with the level of DG. Beef evaluated at 72 h post-mortem showed greater content of γ-tocopherol and retinol as the DG level increased. Meat color was not affected by DG inclusion, but color parameters decreased with retail conditions. Meat from animals fed with DG showed the lowest values of thiobarbituric acid reactive substances (TBARS), independently of the retail display conditions. However, all samples were below the threshold associated with rancid aromas and above the a* value related to meat color acceptance. Thus, feeding diets including up to 45% of DG improved the antioxidant status of meat, preserving the color, and delaying lipid oxidation in meat samples under the display conditions evaluated.

Processing of Distillery Stillage to Recover Phenolic Compounds with Ultrasound-Assisted and Microwave-Assisted Extractions

This study investigated the effect of ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) conditions (extraction time, acetone concentration, solid-to-solvent ratio) on the efficiency of polyphenol recovery from distillery stillage and antioxidant activity of the extracts. The highest total polyphenol content, flavonoid content, and phenolic acid content were obtained with 10-min UAE and 5-min MAE at a solid-to-acetone ratio of 1:15 (w:v). Recovery yield was the highest with an aqueous solution of 60% acetone, confirming the results of Hansen Solubility Parameter analysis. Although UAE resulted in approximately 1.2 times higher extraction yield, MAE showed a better balance between extraction yield and energy consumption exhibited by its 3-fold higher extraction rate than that of UAE. Content of total polyphenols and phenolic acids strongly correlated with antioxidant activity, indicating that these compounds provide a substantial contribution to the bioactive properties of the extracts. Six phenolic acids were extracted, predominately ferulic and p-coumaric acids, and free forms of these acids constituted 91% of their total content, which opens various possibilities for their application in the food, cosmetics, and pharmaceutical industries.

Impacts of bunk management on steer performance and ruminal hydrogen sulfide concentrations in steers fed modified distillers grains with solubles

Two experiments were conducted to evaluate the impacts of bunk management on dry matter intake (DMI), growth performance, carcass characteristic, and hydrogen sulfide (H₂S) concentrations in beef steers fed modified distillers grains with solubles (MDGS; DM basis). In Experiment 1, 139 steers (440.4 ± 31.0 kg) were randomly assigned to one of 16 pens with pen randomly assigned to one of two treatments: 1) Control (CON, bunks managed to be devoid of feed prior to feeding), or 2) Over-fed (OVF, bunks managed to have minimum of 2.54 cm of feed remaining each morning) during adaptation. Following adaptation all steers in Experiment 1 were transitioned to CON bunks and followed to finishing. In Experiment 2, 126 steers (445.4 ± 40.63 kg) were randomly assigned to one of 16 pens. Treatments in Experiment 2 were arranged in a 2 × 2 factorial and include the two bunk management strategies utilized in Experiment 1 (OVF or CON) and either 25% MDGS or 50% MDGS (DM basis). Ruminal H₂S was measured via rumenocentesis during dietary adaptation. There were no differences (P ≥ 0.13) observed in either experiment for growth performance due to bunk management. In Experiment 1, OVF steers had greater (P = 0.001) DMI during adaptation; however, overall DMI was not different (P = 0.14) between treatments. In Experiment 2, DMI (d 0 to 104) tended to decrease (P = 0.09) with greater MDGS inclusion. Hot carcass weight, ribeye area, marbling score, and quality grade were not affected (P ≥ 0.48) by either bunk management or MDGS inclusion. In Experiment 2, back fat (1.30 vs. 1.17 ± 0.042 cm) and yield grade (3.2 vs. 3.0 ± 0.11) were greater (P = 0.03) for CON steers compared with OVF but were not affected (P = 0.59) by MDGS inclusion. In Experiment 1, H₂S tended (P = 0.07) to be greater in steers on OVF compared with CON. In Experiment 2, bunk management strategy did not impact (P = 0.82) H₂S concentrations. There was a MDGS inclusion × day interaction for H₂S with steers fed 50% MDGS having greater (P < 0.01) H₂S concentrations compared with steers fed 25% MDGS on d 28 and 35. Bunk management strategy during adaptation did not impact growth performance but did reduce intake in Experiment 1. Yield grade decreased when OVF bunk management was applied throughout Experiment 2. Response of H₂S concentrations in the rumen were variable and likely influenced by inconsistencies in bunk management and resulting DMI during the early portions of the feedlot study.

Effects of bismuth subsalicylate and encapsulated calcium-ammonium nitrate on feedlot beef cattle production

Two experiments were performed to evaluate the effects of bismuth subsalicylate (BSS) and calcium-ammonium nitrate (CAN) on in vitro ruminal fermentation, growth, apparent total tract digestibility of nutrients, liver mineral concentration, and carcass quality of beef cattle. In Exp. 1, four ruminally cannulated steers (520 ± 30 kg body weight [BW]) were used as donors to perform a batch culture and an in vitro organic matter digestibility (IVOMD) procedure. Treatments were arranged in a 2 × 2 factorial with factors being BSS (0 or 0.33% of substrate dry matter [DM]) and CAN (0 or 2.22% of substrate DM). In Exp. 2, 200 Angus-crossbred steers (385 ± 27 kg BW) were blocked by BW and allocated to 50 pens (4 steers/pen) in a randomized complete block design with a 2 × 2 + 1 factorial arrangement of treatments. Factors included BSS (0 or 0.33% of the diet DM) and nonprotein nitrogen (NPN) source (urea or encapsulated CAN [eCAN] included at 0.68% or 2.0% of the diet, respectively) with 0.28% ruminally available S (RAS). A low S diet was included as a positive control containing urea (0.68% of DM) and 0.14% RAS. For Exp. 1, data were analyzed using the MIXED procedure of SAS with the fixed effects of BSS, CAN, BSS × CAN, and the random effect of donor. For Exp. 2, the MIXED procedure of SAS was used for continuous variables and the GLIMMIX procedure for categorical data. For Exp. 1, no differences (P > 0.230) were observed for IVOMD. There was a tendency (P = 0.055) for an interaction regarding H2S production. Acetate:propionate increased (P = 0.003) with the addition of CAN. In Exp. 2, there was a NPN source effect (P = 0.032) where steers consuming urea had greater carcass-adjusted final shrunk BW than those consuming eCAN. Intake of DM (P < 0.001) and carcass-adjusted average daily gain (P = 0.024) were reduced by eCAN; however, it did not affect (P = 0.650) carcass-adjusted feed efficiency. Steers consuming urea had greater (P = 0.032) hot carcass weight, and a BSS × NPN interaction (P = 0.019) was observed on calculated yield grade. Apparent absorption of S decreased (P < 0.001) with the addition of BSS. Final liver Cu concentration was reduced (P = 0.042) by 58% in cattle fed BSS, indicating that BSS may decrease Cu absorption and storage in the liver. The results observed in this experiment indicate that BSS does not have negative effects on feedlot steer performance, whereas CAN may hinder performance of steers fed finishing diets.

Initial Liver Copper Status in Finishing Beef Steers Fed Three Dietary Concentrations of Copper Affects Beta Agonist Performance, Carcass Characteristics, Lipolysis Response, and Muscle Inflammation Markers

Simple Summary

Beta agonists are commonly used in the United States beef industry, offering improved performance in the days leading up to harvest by influencing energy metabolism. Copper has been shown to regulate the biological pathway leading to increased lipid mobilization. However, this connection has not been evaluated in cattle. Therefore, the objective of this study was to determine how Cu influences beta agonist-induced performance, energy metabolism and inflammation in feedlot cattle. Supplementation of Cu resulted in increased liver Cu concentrations, while cattle performance, lipolysis, and some markers of inflammation responded to Cu supplementation differently, depending on whether or not cattle were fed a beta agonist. Therefore, strategic supplementation of Cu may help optimize growth of cattle receiving a beta agonist.

Abstract

Ninety-three Angus-crossbred steers (470 ± 35 kg) were assigned to a 3 × 2 factorial to determine the effects of Cu status and beta agonist (BA) on performance, carcass characteristics, lipolytic rate, and muscle inflammation. Factors included Cu supplementation (mg Cu/kg dry matter (DM)) at: 0 (LO), 10 (MED), or 20 (HI) from Cu amino acid complex (Availa Cu; Zinpro) with no BA (NoRAC) or 300 mg·steer⁻¹·day⁻¹ of ractopamine hydrochloride (RAC; Optaflexx; Elanco) for final 28 days of 88-day trial. Linear and quadratic effects of Cu status within BA treatment were tested. Pre-BA gain was not affected by Cu supplementation (p ≥ 0.57), although day 53 liver Cu quadratically increased (p = 0.01). Average daily gain and muscle IL-8 gene expression quadratically increased (p ≤ 0.01), with MED having greatest gain and gene expression. Ribeye area tended to quadratically increase with Cu supplementation within RAC (p = 0.08). In vitro basal lipolytic rate tended to quadratically increase with Cu supplementation within RAC (p = 0.11), while stimulated lipolytic rate tended to linearly increase within NoRAC (p = 0.10). These data suggest lipolysis and the BA response of steers are influenced by dietary and liver Cu concentrations.

Effects of replacing wet distillers grains with supplemental SoyPass in forage-based growing cattle diets

One hundred twenty individually fed steers (initial BW 283 kg ± 32) were utilized in an 84-d growing trial to evaluate the effects of increased metabolizable lysine from non-enzymatically browned soybean meal (SoyPass) in grass hay-based diets containing wet distillers grains plus solubles (WDGS). The treatments were arranged as a 2 × 3 factorial with two levels of protein supplement as 20% (low; DL20) or 35% (high; DL35) of dietary DM using WDGS as the basal protein source, and three increments of SoyPass (SP) replacing 0%, 30%, or 60% of the WDGS DM in the protein supplement yielding six dietary treatments. Average daily gain (ADG), dry matter intake (DMI), gain:feed (G:F), and plasma urea N (PUN) data were analyzed using the MIXED procedure of SAS as a 2 × 3 factorial. Animal was the experimental unit and fixed effects included body weight block, dietary inclusion of distillers grains (DL20, DL35), dietary inclusion of SoyPass (SP) (3 levels), and DL × SP inclusion interactions. Linear and quadratic interactions between DL and SP inclusion were analyzed using covariate regression. No interactions were detected for ADG between SP and DL (P = 0.76). Additionally, SP had no effect on ADG (P = 0.49). However, ADG was increased for steers consuming the DL35 diet compared to DL20 (1.13 vs. 0.86 kg/d, respectively; P < 0.01). A DL × SP interaction was detected for DMI (P = 0.01). As SP replaced WDGS in the DL35 diet, DMI increased linearly from 8.10 to 8.93 kg/d (P = 0.02). In the DL20 diet, DMI was not different as SP replaced WDGS (P ≥ 0.11). Therefore, G:F tended to decrease linearly (P = 0.06) as SP replaced WDGS in the DL35 diet, while no difference (P ≥ 0.11) was detected in the DL20 diet, suggesting SP contained less energy than WDGS but did improve dietary lysine balance. Furthermore, plasma urea nitrogen (PUN) increased linearly as SP replaced WDGS in the DL20 diet (P < 0.01) but was not affected by SP substitution in the DL35 diet (P ≥ 0.19). When WDGS is fed at a low (20% DM) or high (35% DM) inclusion rate in a forage-based diet, replacing the distillers with a source of protected amino acids supplied through heat-treated soybean meal, did not improve performance. A more concentrated or energy-dense form of amino acids may be beneficial in forage-based growing cattle diets containing 20% distillers grains but is not needed in diets with 35% distillers grains.

Impact of different levels of low-fat dried distillers grains on performance of young Nellore bulls during the finishing phase

This study evaluated the effect of including low-fat dried distillers grains (DDG) on young Nellore bulls performance, nutritional parameters, and nitrogen metabolism. Thirty-five Nellore cattle were randomly divided into four diets: without dried distillers grains (D0) or with the inclusion of DDG at 150 g/kg (D150), 300 g/kg (D300), or 450 g/kg (D450). The evaluation period lasted 126 days, and three periods of collection of feces and urine were carried out. Final body weight (P = 0.099) and average daily gain (P = 0.097) tended to decrease linearly; the digestibility of dry matter (P < 0.001), organic matter (P < 0.001), ether extract (P < 0.001) and nonfiber carbohydrates (P < 0.001), and intakes of total digestible nutrients (TDN, P < 0.001) decreased linearly. The increase in crude protein intake (P < 0.001) did not result in an increase in the amount of nitrogen retained (P = 0.540). We concluded that the inclusion of low-fat DDG in finishing diets up to the level of 450 g/kg tends to reduce animal performance and the intake of TDN.

Fatty Acid Composition of Meat Animals as Flavor Precursors

This article provides an overview of fatty acids in meat, their variation among animal species, and the roles of fatty acids as flavor precursors. Animal fat mostly consists of triglycerides and phospholipids. Fats from ruminant (cattle, sheep, and goats) and monogastric (pigs and horses) animals have similar fatty acids with more saturated fatty acids and monounsaturated fatty acids than polyunsaturated fatty acids. In monogastric animals, fatty acids in the muscle reflect the composition of diets, whereas ruminant fatty acids are more saturated because of biohydrogenation in the rumen. Lipid- derived flavor compounds are formed from the thermal oxidation of fatty acids during cooking, producing more desirable aromatic compounds than autoxidation. Monounsaturated fatty acids such as oleic acid and polyunsaturated fatty acids such as linoleic acid in meat produce various volatile compounds contributing to cooked meat aromas. Under most cooking conditions, lipid-derived flavor compounds are usually predominant. However, these compounds have greater thresholds than those derived from water-soluble compounds, such as the Maillard reaction products. The interactions between lipid oxidation products and Maillard compounds are more important for the development of meat flavor than originally thought. Moreover, fat-derived volatile compounds provide flavor notes indicative of species identification.

Investigating the Effects of Distillers Grains on Heifer Feeding Behavior in the Finishing Phase

Simple Summary

Dried distillers grains (DDG), a corn by-product of the ethanol industry, are a common feedstuff in cattle diets. Distillers can be used in diets as an effective source of protein and can reduce risk of acidosis by reducing the highly fermentable carbohydrate of starch. However, the price and availability of distillers grains are variable based on droughts, energy prices, and other factors. When inclusion of distillers grains in diets becomes uneconomical or is not possible, diets may decrease in crude protein and increase in starch-altering rumen fermentation parameters and feeding behavior. The effect of distillers grains on cattle growth performance and carcass traits has been studied extensively, but little is known about how distillers inclusion affects feeding behavior. Therefore, the objective of this experiment was to determine the effect of low inclusion levels of DDG on feeding behavior in heifers consuming a high-moisture corn-based diet in the finishing phase. This study demonstrated that low inclusion levels of distillers grains has little effect on growth performance, but can alter feeding behavior and reduce variability in feeding behavior traits.

Abstract

The objective was to determine the effect of low inclusion levels of dried distillers grains (DDG) on feeding behavior in heifers consuming a high-moisture corn-based diet in the finishing phase. Simmental × Angus heifers (N = 90; 323 ± 50 kg) were fed for 180 d. Heifers were blocked by initial body weight (BW) into two groups, stratified by sire, and assigned to 15 pens with six heifers each. Pens were randomly assigned to one of three dietary treatments: 0% DDG inclusion (0DG), 7% DDG inclusion (7DG), or 14% DDG inclusion (14DG). Treatments did not affect (p > 0.59) BW, average daily gain, and gain:feed. Although there was a treatment × time effect (p = 0.05) for dry matter intake (DMI), with 0DG having greater DMI during the last 70 d, no differences in overall DMI were detected. Treatment affected (p < 0.01) bunk visit duration and head down duration, with 7DG and 14DG having less minutes per day. Bunk visit frequency (p = 0.02) was less variable for heifers fed 14DG and DMI tended (p = 0.08) to be less variable for both distillers treatments. While dietary inclusion of DDG has minimal effects on overall heifer performance, low levels of DDG inclusion can affect feeding behavior and intake variation.

Effect of dietary inclusion of graded levels of distillers dried grains with solubles on the performance, blood profile and rumen microbiota of Najdi lambs

An experiment was conducted in a completely randomized design to evaluate the effect of including graded levels (0, 20, 30, 40 and 50% of diet) of dried distiller's grains with solubles (DDGS) on growth performance, slaughter parameters, blood serum metabolites and rumen microbiota in weaned Najdi male lambs. Thirty-five lambs, initial body weight of 33.45 ± 0.75 kg, and approximately three-month old were used in a 94-day feeding experiment. Performance measurements were conducted biweekly and blood samples were collected monthly. Inclusion of DDGS in the diets of growing Najdi lambs at levels up to 50% did not affect body weight gain (BWG) compared with the lambs fed the control diet (CON, 0% DDGS). Lambs fed the 50% DDGS diet consumed less feed compared with lambs in other groups (98 vs 112.5 kg DM) but had no adverse effect on BWG. Rumen pH values at 0, 6, 12 and 18 h post feeding and concentrations of blood serum total proteins, glucose, triglycerides, urea-N or albumin were similar across treatments. Slaughter parameters including slaughter weight, hot and cold carcass weights and dressing % (hot and cold carcass) were not affected by the treatments. There was no difference in the weights of full compartmental stomach and intestines, liver, omental fat, Kidney Knob and Channel Fat (KKCF) and tail fat between DDGS treatments and CON. The study concluded that the inclusion of DDGS in the diets of growing Najdi lambs had no adverse effects on growth performance and slaughter parameters. Rumen microbiota was not affected, however, our data suggest significant interactions between DDGS and selected bacterial groups and DDGS driven rearrangement of Prevotella species.

Does the length of time dried distillers' grain with solubles substitution for soybean meal affect physiological indicators and meat quality in finishing lambs?

This study examined how inclusion of dried distillers' grains with solubles (DDGS) in finishing lamb diets for different periods affects some physiological indicators and meat quality. A total of 40 male lambs were divided into four groups according to feeding regimen during the 120-day finishing period as follows: C120: no DDGS included in diet for 120 days; D120: DDGS included in diet for 120 days; D75: no DDGS included in diet for 45 days + DDGS included in diet for 75 days; D45: no DDGS included in diet for 75 days + DDGS included in diet for 45 days. Dietary inclusion rate of DDGS was 27.5%. Fattening performance and rumen parameters were not affected by treatment. Feeding regimens had no significant effect on meat quality except the instrumental tenderness and juiciness score. DDGS fed lambs had higher level of total trans fatty acids and n-6/n-3 ratio in meat. 10t-C18:1, 11t-C18:1 and 9c,11t conjugated linoleic acid contents of adipose tissue were higher in all the DDGS groups compared with C120 lambs (p < .001). These results suggest that soybean meal can be replaced with corn DDGS in lamb diets for up to 120 days during the finishing period with no adverse effects on some physiological response feedlot performance and meat quality.

Effects of feeding 60% dried corn distillers grains plus solubles or the equivalent sulfur as CaSO4 on performance and reproductive traits of yearling Angus bulls

The objectives of this study were to investigate the effects of feeding 60% dried corn distillers grains plus solubles (DDGS) or the equivalent sulfur as calcium sulfate (CaSO₄) on semen quality and performance characteristics in yearling bulls. Thirty-six half-sibling Angus bulls [291 ± 8.5 d; initial body weight (BW) = 320 ± 2.7 kg] were assigned to one of three diets: 1) 60% concentrate as corn (CON; S = 0.18%; n = 12); 2) 60% DDGS replacing corn (60DDGS; S = 0.55% DM; n = 12); 3) CON + equivalent sulfur of 60DDGS added as CaSO₄ (SULF; S = 0.54%; n = 12). Bulls were fed for 112 d to target an average daily gain (ADG) of 1.6 kg/d. Blood samples were collected on d 0, 56, and 112, and evaluated for testosterone, thyroxine, triiodothyronine (T3) and glutathione peroxidase (GP_x) activity. Ruminal H₂S was measured on d 0, 14, and 42. Scrotal circumference and semen were collected on d 0, 28, 56, 84, and 112 to evaluate sperm characteristics and GP_x activity in seminal plasma. A computer assisted semen analysis was used to evaluate kinematic profiles in motile and progressive sperm throughout the study. Data were analyzed as repeated measures using MIXED procedures of SAS. No differences (P ≥ 0.14) were observed for final BW, ADG, or scrotal circumference; however, SULF tended (P = 0.07) to have reduced gain:feed compared with CON, with 60DDGS being intermediate. Concentrations of ruminal H₂S on d 42 were greatest (P < 0.01) for SULF. Increased ejaculate volume was observed for 60DDGS and CON (P < 0.01) compared with SULF. For motile populations of sperm, velocity on an average path (VAP) and curvilinear velocity (VCL) were reduced (P ≤ 0.02) for SULF compared with CON, with 60DDGS being intermediate. In progressively motile sperm throughout the study, VAP and VSL were reduced (P ≤ 0.05) in 60DDGS and SULF compared to CON. For VCL, SULF was reduced (P ≤ 0.02) compared with CON, with 60DDGS being intermediate. In serum, concentrations of T3 were reduced (P = 0.009) in 60DDGS compared with CON or SULF. A treatment by day interaction (P = 0.03) was observed for seminal plasma GP_x. At d 56, GP_x activity was greater (P = 0.03) for 60DDGS compared with CON, with SULF intermediate; and at d 112, 60DDGS had the greatest (P ≤ 0.02) GP_x activity. Therefore, feeding 60% DDGS to developing bulls altered semen kinematics, T3 concentrations, and GP_x activity leading to the conclusion that these differences may not be solely dependent on concentrations of dietary sulfur.

Fatty acid composition, shelf-life and eating quality of beef from steers fed corn or wheat dried distillers' grains with solubles in a concentrate supplement to grass silage

Thirty-six steers were randomly assigned to one of three dietary treatments fed ad libitum grass silage and concentrate supplements containing either barley/soybean meal (CON), 80% DM corn (CDGS)- or 80% DM wheat (WDGS)-dried distillers' grains with solubles for 124 days pre-slaughter. Chemical and fatty acid composition, shelf-life, and eating quality of longissimus thoracis muscle were determined. Dietary CDGS and WDGS increased the proportion of conjugated linoleic acids (P < 0.05) and tended to increase C18:3n-3 (P = 0.075) and total polyunsaturated fatty acids (P = 0.060) relative to the CON. Feeding diets containing distillers' grains reduced the lipid and colour stability of fresh beef patties stored in modified atmosphere packs (MAP), with CDGS exhibiting an intermediate effect between CON and WDGS. Diet did not negatively influence the texture profile parameters and eating quality attributes of beef stored in MAP. The inclusion of CDGS or WDGS in supplementary concentrates may improve the fatty acid profile but decreased the shelf-life of beef.

Quantitative Analysis of Ethyl Carbamate in Distillers Grains Co-products and Bovine Plasma by Gas Chromatography-Mass Spectrometry

Ethyl carbamate (EC) is a fermentation byproduct in foods and beverages and classified as a Group 2A probable human carcinogen. Each year, greater than 40 million metric tons of fermentation co-products from the U.S. ethanol industry are fed to food animals. A gas chromatography-mass spectrometry assay was developed to quantify EC extracted from various distillers grains co-products with a limit of detection at 0.7 ng/g (on an as-fed basis). EC was detected in all the distillers grains co-products surveyed in this study. Corn condensed distillers solubles contained the highest concentration of EC, ranging from 1618 to 2956 ng/g. Concentrations of EC in other types of distillers grains co-products varied from 17 to 917 ng/g. Cattle fed distillers grains co-products that constituted 19-38% of the total feed (as-fed) were found to contain 2-3 ng/mL of EC in blood plasma. No EC was detected in blood plasma from grass-fed control cattle.

Effects of dietary replacement of soybean meal with dried distillers grains with solubles on the microbiota occupying different ecological niches in the rumen of growing Hu lambs

Background

Diet has a profound impact on the rumen microbiota, and the impact can vary among the different rumen ecological niches (REN). This study investigated the effects of dietary replacement of soybean meal (SBM) with dried distillers grains with solubles (DDGS) on the rumen microbiota occupying different REN of growing Hu lambs. After a 9-week feeding trial, 6 lambs from each dietary treatment (SBM vs. DDGS-based diets) were slaughtered for sample collection. The microbiota of the rumen solid, liquid, and epithelium fractions was examined using amplicon sequencing analysis of bacterial 16S rRNA gene, functional prediction, and qPCR.

Results

No interaction of dietary protein source (PS) and REN were detected for virtually all the measurements made in this study. The DDGS substitution resulted in very limited influence on bacterial community structure. However, the metabolic pathways predicted from 16S rRNA gene sequences varied greatly between SBM- and DDGS-based diets. The populations of rumen total bacteria, fungi, sulfate-reducing bacteria (SRB), and methanogens were not influenced by DDGS substitution, but the population of protozoa was reduced. The bacterial communities in rumen solid (RS) and liquid (RL) were similar in taxonomic composition but were different in relative abundance of some taxa. In contrast, the bacterial composition and relative abundance of rumen epithelium (RE) were greatly distinct from those of the RS and the RL. In alignment with the bacterial relative abundance, the metabolic pathways predicted from 16S rRNA genes also varied greatly among the different REN. The populations of total bacteria, protozoa, and methanogens attached to the RE were smaller than those in the RS and RL, and the fungal population on the rumen epithelium was smaller than that in the RS but similar to that in the RL. On the contrary, the SRB population on the RE was greater than that in the RS and RL.

Conclusions

Substitution of SBM with DDGS had greater impact to the protozoa than to the other microbes, and the microbial community structure and functions at different REN are distinct and niche-adapted.

Effects of distillers dried grains with solubles supplementation on yearling heifers grazing Northern Great Plains rangeland: impacts on subsequent feedlot performance and meat quality

Eighty-two yearling crossbred heifers (318.8 ± 1.03 kg) were utilized in a completely randomized design to evaluate the effects of distillers dried grains with solubles (DDGS) supplementation on animal performance, while grazing on rangeland of the Northern Great Plains, and subsequent feedlot performance, carcass characteristics, and meat quality traits. Treatments were: 1) 0% DDGS supplementation (CONT) and 2) 0.6% of body weight (BW) DDGS supplementation (SUP). Heifers received treatments for 70 d (6 June to 16 August) while grazing, and then were acclimated to and fed a common corn-based finishing diet for 109 d. Average daily gain (ADG) of SUP heifers was greater (P ≤ 0.01), resulting in heavier BW (P ≤ 0.03) following grazing compared with CONT heifers. Heifer performance, including ADG (1.91 ± 0.05 kg/d), gain to feed (G:F) (0.15 ± 0.003 kg), dry matter intake (DMI) (12.6 ± 0.20 kg), and final BW (572.4 ± 7.43 kg) were not different (P ≥ 0.13) during finishing. Hot carcass weight (335.7 ± 4.39 kg), Longissimus muscle area (81.30 ± 1.24 cm²), 12th rib fat thickness (1.24 ± 0.06 cm), and kidney, pelvic, heart fat (KPH) (1.85 ± 0.08%) were not different (P ≥ 0.47) between treatments. There were no differences (P ≥ 0.24) between treatments in yield grade (2.9 ± 0.10) or marbling (492 ± 22.3; Small⁰⁰ = 400). Results from Warner–Bratzler shear force indicated that strip loin steaks from SUP heifers tended (P = 0.07) to have increased tenderness compared with strip loin steaks from CONT heifers (3.3 vs. 3.7 ± 0.12 kg, respectively). Inclusion of 0.6% BW supplementation during grazing increased (P = 0.01) strip loin steak muscle lightness (L*) compared with CONT steaks (46.5 vs. 45.5 ± 0.27, respectively). Strip loin steaks from heifers supplemented DDGS during grazing were perceived to be more tender by taste panelists (P = 0.02) than strip loin steaks from CONT heifers (5.9 vs. 5.5 ± 0.11; eight-point scale). Supplementation of DDGS during grazing improved ADG of yearling heifers with no effect on feedlot performance or carcass characteristics but did improve tenderness and steak sensory attributes.

Effect of replacing conventional feeds with tropical agricultural by-products on the growth performance, nutrient digestibility and ruminal microbiota of water buffaloes

This study investigated the effect of replacing corn grain, soybean meal and wheat bran with tropical agricultural by-products, such as palm kernel cake (PKC), cassava residue and dried distiller's grain with solubles (DDGS), on the dry matter intake (DMI), growth performance, apparent nutrient digestibility, ruminal short-chain fatty acids (SCFA) and ruminal microbial communities of water buffaloes. Thirty healthy 15-month-old crossbred water buffaloes with a similar initial body weight of 353.1 ± 23.7 kg were randomly allocated into three dietary experimental groups, and they were fed with same forage but three different concentrates for 50 days fattening. The dietary treatments were as following: typical concentrate (TC, 65% corn + 15% wheat bran + 15% soybean meal), partial replacement concentrate Ⅰ (PRC I, 50% corn + 22.5% corn gluten + 22.5% PKC) and partial replacement concentrate Ⅱ (PRC II, 50% corn + 22.5% cassava residue + 22.5% DDGS). The results showed that the average daily gain of the PRC II group was the highest, and the DMI, acid detergent fibre digestibility and neutral detergent fibre digestibility value of the three groups were different and in the following order: PRC II group > TC group > PRC I group. The crude protein digestibility of PRC II was higher than that of the TC and PRC I groups (p < .05). The ruminal concentrations of total SCFA, acetate, propionate and butyrate of TC group were higher than the other two groups (p < .05). The PRC I group had the highest Bacteroidetes-to-Firmicutes ratio (B/F) and relative abundance of the genus Prevotella, while the PRC II group had the lowest B/F and relative abundance of Prevotella. In conclusion, using PKC and corn gluten to completely replace common feed ingredients in the buffalo concentrate ration decreased, while using cassava residue and DDGS increased animal growth performance, mainly due to the different combination influenced nutrient digestibility and ruminal microbial community composition was shifted.

Effects of a high-protein corn product compared with soy and canola protein sources on nutrient digestibility and production responses in mid-lactation dairy cows

An experiment was conducted to assess the effects of a novel and proprietary high-protein corn product [56% crude protein (CP)] relative to other common sources of protein on the lactation performance of dairy cows. Twenty-four Holstein cows (620 ± 47.7 kg of body weight, 111 ± 34 d in milk, 2.28 ± 0.46 lactations; mean ± standard deviation) were randomly assigned to treatment sequence in a replicated 4 × 4 Latin square design balanced for carryover effects. Cows were individually fed 1 of 4 diets with a different protein concentrate source during each 28-d period, including soybean meal (SBM), high-protein corn product (HPCP), soybean meal with rumen-bypass soy protein (SBMBP), and canola meal with rumen-bypass soy protein (CANBP). Diets were formulated for equal concentrations of CP and balanced to meet predicted lysine and methionine requirements. The SBM diet was formulated to provide 5.7% rumen-undegradable protein (RUP), whereas SBMBP and CANBP diets were formulated for 6.8% RUP to match HPCP. Data were analyzed using mixed models with the fixed effects of treatment, period, square, the interactions of treatment and period and of treatment and square, and the random effect of cow. The CANBP diet increased dry matter intake (DMI) compared with SBM and HPCP. Treatment affected milk yield, as SBMBP and CANBP increased yield compared with SBM, but HPCP decreased milk yield compared with all treatments. The HPCP diet reduced CP intake as a percent of total DMI and increased the CP content of orts, indicative of selection against HPCP. The HPCP diet also decreased apparent total-tract and CP digestibility, leading to less urine nitrogen excretion and greater fecal nitrogen output. The SBMBP and CANBP diets performed similarly in nearly every variable measured, except that SBMBP increased milk urea nitrogen. In conclusion, the HPCP diet reduced yield of milk and milk components, likely because of reduced apparent total-tract dry matter and CP digestibility.

Optimum roughage proportion in barley-based feedlot cattle diets: total tract nutrient digestibility, rumination, ruminal acidosis, short-chain fatty absorption, and gastrointestinal tract barrier function

Cattle need physically effective fiber to promote rumination and maintain rumen health, but economics favor the use of low-roughage feedlot diets. The study investigated the optimum barley silage proportion in barley-based finishing diets. Apparent total-tract digestibility (4-d total fecal collection), chewing behavior (6-d video recording), ruminal pH (6-d indwelling pH recording), and fermentation (1 day, sampling 0, 3, 6, 12, and 18 h postfeeding), short-chain fatty acid (SCFA) absorption (washed reticulo-rumen technique), gastrointestinal tract barrier function (marker infusion), and blood variables (catheters) were measured. Eight ruminally fistulated crossbred beef heifers (653 ± 44.2 kg; mean starting body weight [BW] ± SD) were used in a replicated 4 × 4 Latin square design with 28-d periods. Dietary treatments were 0%, 4%, 8%, and 12% of dietary dry matter (DM) as barley silage, with diets containing 80%, 76%, 72%, and 68% barley grain, respectively. Increasing silage proportion decreased dietary starch content from 49.0% to 43.1% DM, while neutral detergent content increased from 22.7% to 25.1% DM. Silage proportion had no effect on DM intake, but apparent DM digestibility decreased quadratically (86.0%, 82.1%, 81.1%, 79.5% for the four diets, respectively; P < 0.001). Although, silage proportion had no effect on eating activity, rumination time increased quadratically (246, 289, 302, 316 min/d; P = 0.04). Increased silage proportion increased minimum (5.07, 5.27, 5.29, 5.41; quadratic, P = 0.011) and mean (5.61, 5.87, 5.93, 5.95; quadratic, P = 0.007) ruminal pH, and there was a quadratic (P ≤ 0.047) decrease in duration and area under the pH acidosis threshold curves of 5.8, 5.5, and 5.2. Although increasing silage proportion decreased ruminal acidosis, it was not completely eliminated even with a diet containing 12% silage DM. SCFA concentration in ruminal fluid was not affected by diet, but silage proportion quadratically (P ≤ 0.088) increased ruminal acetate:propionate. There was no effect of diet on absolute or fractional rates of absorption of acetate, propionate, butyrate or total SCFA, and no effect on gastrointestinal barrier function or blood measurements. In conclusion, responses to roughage level were mostly quadratic with greatest improvements in acidosis variables between 0% and 4% barley silage, with incremental improvements with further increases in silage levels. The study showed a trade-off between maximizing digestibility and energy intake to promote animal performance and minimizing the risk of acidosis.

Effects of dietary supplement sources on the rate and extent of in vitro ruminal degradation of alfalfa-based diets for cattle

Two ruminally cannulated steers [928 ± 25.5 kg body weight (BW)] were fed alfalfa hay at 2.0% of BW and served as donors of rumen fluid. Treatments were early-bud alfalfa (CON) or a combination [dry matter (DM) basis] of 80% early-bud alfalfa with 20% of corn silage (CS), brome grass hay (BGH), soybean hulls (SBH), beet pulp (BP), corn grain (CORN), dried corn distillers’ grains with solubles (DDGS), or wheat middlings (MIDD). Tubes were incubated at multiple time points over a 72 h period and assessed for rate and extent of digestion. Samples were run in duplicate and replicated over 3 d. The potential extent of DM and organic matter (OM) degradation increased (P < 0.001) with CS, SBH, BP, CORN, and DDGS supplementation compared with CON. All supplements except MIDD decreased (P < 0.001) the fractional rates of DM and OM degradation compared with CON, with BGH, SBH, and DDGS having the lowest rates. Supplementation of SBH had the lowest (P < 0.001) initial rate of DM and OM degradation. These data indicate that SBH increases the extent of digestion while reducing the initial rate of degradation, suggesting that SBH has potential to reduce the incidence of frothy legume bloat.

Association of leptin genotype with growth performance, adipocyte cellularity, meat quality, and fatty acid profile in beef steers fed flaxseed or high-oleate sunflower seed diets with or without triticale dried distiller's grains

Leptin genotypes can be identified as homozygous normal (CC), homozygous mutant (TT), and heterozygous (CT) based on a single-nucleotide polymorphism in exon 2 of the leptin gene, which has been associated with feed intake and fat deposition in cattle. The experiment was designed as 2 × 2 × 2 factorial with three main factors: (1) genotype (CT or TT) and diets fed 2) with or without triticale dried distiller's grains with solubles (DDG), and 3) with either flaxseed (FS) or high-oleate sunflower seed (SS). Evaluations included growth performance, subcutaneous fat deposition, adipocyte cellularity, meat quality, and fatty acid (FA) profile of various depots. Beef steers (n = 40, 459 ± 31 kg) of either CT or TT genotypes were housed in individual pens with ad libitum access to one of the four diets: 75% steam-rolled barley + 10% barley silage with 10% FS or SS (non-DDG diets, NDG) and 46.5% barley + 10% barley silage + 30% DDG, with 8.5% FS or SS, all on a dry matter basis. Growth performance, ultrasound subcutaneous fat thickness, rib eye area (REA), and plasma FA were measured prior to and during the finishing period. At slaughter, samples of subcutaneous fat, perirenal fat, and Longissimus thoracis (LT) muscle were collected for FA analysis and carcass and meat quality were measured. Compared with CT cattle, TT tended to have less (P = 0.06) C18:2-c9,t11 (rumenic acid) in plasma and subcutaneous fat and a greater proportion (P < 0.05) of C18:0 in subcutaneous, perirenal, and LT fat. Cattle with TT genotype also tended (P < 0.1) to have more total saturated and less unsaturated (USFA) and monounsaturated fats (MUFA) and had less (P = 0.04) linoleic acid in LT. Ultrasound fat thickness, REA, and average diameter of adipocytes in subcutaneous fat at 12 wk were not affected (P > 0.39) by genotype. Generally, carcass and meat quality were similar (P > 0.1) among diets, although adding FS tended to increase (P = 0.06) total USFA of subcutaneous fat including omega-3 FA (P < 0.001). For the high-fat diets evaluated, CT cattle would have more potential to produce beef with enhanced health benefits than would TT cattle.

Effects of Muscle and Finishing Diets Containing Distillers Grains with Low Moisture Levels on Fatty Acid Deposition in Two Novel Value-added Beef Cuts

This study evaluated the effects of muscle and dietary treatments including CORN, dry distillers grains (DDGS), and modified distillers grains (MDGS) on fatty acid (FA) deposition in two novel value-added beef cuts (Petite Tender - M. teres major - TM, and Flat Iron - M. infraspinatus - INF). Crossbred steers were randomly assigned to one of three dietary treatments (CORN, 40% of DDGS with 8%-12% of moisture, and 40% of MDGS with 45%-55% of moisture - DM basis) and fed for 190 days. The TM muscle had higher concentrations of ω6 FAs and polyunsaturated fatty acids (PUFA) when compared to INF. Beef fed CORN showed greater C16:0 and lower C18:0 values when compared to beef fed distillers grains (DGS). Beef fed DDGS had higher concentrations of ω6 FAs when compared to MDGS. Different moisture levels only affected FAs containing 14, 16, and 17 carbons. Different muscles, diets, and moisture levels of DGS affected the deposition of FAs in the lean.

Associative effects of wet distiller's grains plus solubles and tannin-rich peanut skin supplementation on in vitro rumen fermentation, greenhouse gas emissions, and microbial changes1

Two sets of in vitro rumen fermentation experiments were conducted to determine effects of diets that included wet distiller's grains plus solubles (WDGS) and tannin-rich peanut skin (PS) on the in vitro digestibility, greenhouse gas (GHG) and other gas emissions, fermentation rate, and microbial changes. The objectives were to assess associative effects of various levels of PS or WDGS on the in vitro digestibility, GHG and other gas emissions, fermentation rate, and microbial changes in the rumen. All gases were collected using an ANKOM Gas Production system for methane (CH4), carbon dioxide (CO2), nitrous oxide (N2O), and hydrogen sulfide (H2S) analyses. Cumulative ruminal gas production was determined using 250 mL ANKOM sampling bottles containing 50 mL of ruminal fluid (pH 5.8), 40 mL of artificial saliva (pH 6.8), and 6 g of mixed diets after a maximum of 24 h of incubation. Fermenters were flushed with CO2 gas and held at 39 °C in a shaking incubator for 24 h. Triplicate quantitative real-time polymerase chain reaction (qPCR) analyses were conducted to determine microbial diversity. When WDGS was supplied in the diet, in the absence of PS, cumulative CH4 production increased (P < 0.05) with 40% WDGS. In the presence of PS, production of CH4 was reduced but the reduction was less at 40% WDGS. In the presence of PS, ruminal lactate, succinate, and acetate/propionate (A/P) ratio tended to be less with a WDGS interaction (P < 0.01). In the presence of PS and with 40% WDGS, average populations of Bacteroidetes, total methanogens, Methanobrevibacter sp. AbM4, and total protozoa were less. The population of total methanogens (R2 = 0.57; P < 0.01), Firmicutes (R2 = 0.46: P < 0.05), and Firmicutes/Bacteroidetes (F/B) ratio (R2 = 0.46; P < 0.03) were strongly correlated with ruminal CH4 production. Therefore, there was an associative effect of tannin-rich PS and WDGS, which suppressed methanogenesis both directly and indirectly by modifying populations of ruminal methanogens.

Influence of distillers grains with solubles on bull growth and reproductive traits

This study evaluated the effects of offering growing bulls a diet with 40% modified wet distillers grains plus solubles (MWDGS; dry matter [DM] basis) on growth, composition, hoof scores, and reproductive performance. Simmental × Angus bulls (n = 28) were stratified by body weight (BW; 316 ± 29 kg), sire, and day 0 semen production (Y/N) and assigned into one of six pens. Pens were randomly assigned to one of two dietary treatments (n = 3 pens/treatment): 1) offered free-choice access to a corn-based diet with no MWDGS (CON) or 2) offered free-choice access to a diet with 40% MWDGS (DST; DM basis). Bulls were offered treatments for 140 d and, then, switched to a free-choice, common, low-energy diet for an additional 70 d. Bull BW, body condition score (BCS), hip height (HH), ultrasound (rump fat depth [RF], 12th rib fat thickness [BF], marbling score [MS], and longissimus muscle depth [MD]), hoof evaluations, breeding soundness examination (BSE), and semen evaluations were performed on days 0, 28, 56, 84, 112, 140, 175, and 210. There was a tendency (P < 0.09) for a treatment × time effect for BW. Bulls fed DST tended (P ≤ 0.10) to be heavier on days 28 and 56 than CON bulls. A treatment × time effect was detected (P < 0.01) for RF. Bulls fed DST had greater (P = 0.02) RF on day 84 than CON bulls. Treatment × time and treatment effects were detected (P ≤ 0.05) for BF, in which DST bulls had greater (P ≤ 0.05) BF on days 84, 112, and 175 and tended (P ≤ 0.10) to be greater on days 56 and 210 than CON bulls. A treatment × time effect was detected (P < 0.02) for percentage of major sperm defects. Bulls fed DST had a greater (P < 0.01) percentage of major sperm defects on day 140 than control bulls. There was a tendency (P = 0.09) for a treatment × time effect for percentage of sperm with proximal droplets. Bulls fed DST had a greater (P = 0.01) percentage of sperm with proximal droplets on day 140 than CON bulls. In conclusion, offering growing bulls a diet with 40% MWDGS (DM basis) resulted in heavier BW at days 28 and 56, increased RF at day 84, and increased BF and increases in both major sperm defects and sperm with proximal droplets at day 140. However, after 70 d on the common low-energy diet, there were no carryover effects for any growth, composition, hoof, or reproductive measures except for a tendency for BF.

Meat quality traits and feeding distillers grains to cattle: a review

Livestock management and meat production involve a series of steps that affect meat quality. Animal genetics, nutrition and diets, slaughter procedures and meat-preservation conditions are some of the parameters that should be controlled to maintain meat quality. In regard to animal nutrition and diets, novel ingredients are increasingly used, distillers grains (DG) being an example. DG are obtained as a co-product from bioethanol production and comprise the fat, protein, fibre and micronutrient portion of the grains. Many papers have studied the inclusion of DG in finishing diets and their effect on growth performance and meat characteristics, but a review on the effects on meat quality is needed. Feeding with DG influences beef colour; nevertheless, a relationship between the level of inclusion and colour development has not been established yet. In addition, feeding DG-inclusion diets sometimes increases meat discoloration during retail display. Also, the composition of fatty acids is modified since total polyunsaturated fatty acid content in meat increases with the inclusion of DG in finishing diets. This increment in polyunsaturated fatty acid content is likely to contribute to lipid oxidation processes and might be related to meat discoloration due to myoglobin oxidation. However, meat tenderness has not been modified in most of the cases. This review focused on recent studies on DG inclusion, animal performance and meat quality. Key points that need further research are also identified and discussed.

Growth Performance and Carcass Traits Responses to Dried Distillers' Grain with Solubles Feeding of Growing Awassi Ram Lambs

Simple Summary

Corn grain is considered to be the most important crop in the world. Corn dried distiller grains with solubles is a by-product of ethanol production. It is included at 0, 125, or 25 g/kg in lambs’ diets. This inclusion reduced the cost of diet, indicating the good possibility of using it in small ruminant diets.

Abstract

This study considers the impact of dried distillers’ grain with solubles (DDGS) in diets of lambs. Randomly; 27 lambs were distributed to one of three diets. Diets were: a control diet (CON; n = 9), a 125 (DDGS125; n = 9) or a 250 g/kg DDGS (DDGS250; n = 9) of dietary dry matter (DM). The lambs were fed using these diets for 91 days. To assess carcass traits; five lambs were randomly selected at the end of the study. No significant differences were detected in intake and digestibility of DM; crude protein and fiber. Average daily gain did not differ among diets. Carcass characteristics did not differ among diets. With the exception of shear force and redness, which were greater in DDGS250 than in DDGS125 and CON diets, meat quality parameters were unaffected. Eye muscle area decreased in DDGS125 than in DDGS250 and CON diet. These results demonstrate that the feeding of lambs on DDGS at 125 or 250 g/kg DM did not have any impact on growth. These diets only had a simple effect on the characteristics of carcass and meat quality. These results suggest that it would be suitable to introduce these feeds into sheep nutrition in the future.

Performance, beef quality and expression of lipogenic genes in young bulls fed low-fat dried distillers grains

Two studies were carried out, the first with the objective to evaluate performance, beef quality and expression of genes involved in lipid metabolism in the muscle of bulls fed with or without low-fat dried distillers grains with solubles (DDGS, 21% DM) in the diet. In the second, eight rumen-fistulated bulls were assigned in a switch back design to evaluate the fatty acid profile of omasal fluid. We hypothesized that bulls fed DDGS may have an improved fatty acid profile and expression of genes involved in lipid metabolism may be altered, without affecting performance. Bulls fed DDGS had greater (P < .05) concentrations of PUFA n-6 in the omasum and muscle. CLA t10, c12 content was higher and there was lower expression of the LPL gene (P = .05) in the muscle of animals fed DDGS (P = .03). In conclusion, DDGS can be used as a protein feedstuff because it maintains beef quality.