Effect of dietary protein source and Saccharina latissima on nutritional and safety characteristics of milk.

BACKGROUND: Wheat distillers' grains (WDG) and seaweeds are recommended as alternative protein sources and enteric methane mitigators in dairy cow diets, respectively, but little is known about their impact on milk quality and safety. In the present study, 16 cows in four 4 × 4 Latin squares were fed isonitrogenous diets (50:50 forage:concentrate ratio), with rapeseed meal (RSM)-based or WDG-based concentrate (230 and 205 g kg-1 dry matter) and supplemented with or without Saccharina latissima. RESULTS: Replacement of RSM with WDG enhanced milk nutritional profile by decreasing milk atherogenicity (P = 0.002) and thrombogenicity (P = 0.019) indices and the concentrations of the nutritionally undesirable saturated fatty acids - specifically, lauric (P = 0.045), myristic (P = 0.022) and palmitic (P = 0.007) acids. It also increased milk concentrations of the nutritionally beneficial vaccenic (P < 0.001), oleic (P = 0.030), linoleic (P < 0.001), rumenic (P < 0.001) and α-linolenic (P = 0.012) acids, and total monounsaturated (P = 0.044), polyunsaturated (P < 0.001) and n-6 (P < 0.001) fatty acids. Feeding Saccharina latissima at 35.7 g per cow per day did not affect the nutritionally relevant milk fatty acids or pose any risk on milk safety, as bromoform concentrations in milk were negligible and unaffected by the dietary treatments. However, it slightly reduced milk concentrations of pantothenate. CONCLUSION: Feeding WDG to dairy cows improved milk fatty acid profiles, by increasing the concentrations of nutritionally beneficial fatty acids and reducing the concentration of nutritionally undesirable saturated fatty acids, while feeding seaweed slightly reduced pantothenate concentrations. However, when considering the current average milk intakes in the population, the milk compositional differences between treatments in this study appear relatively small to have an effect on human health. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Characterization and nutritional value of hydrothermal liquid products from distillers grains.

Hydrothermal liquid products (HLPs) produced by hydrothermal treatment (HTT) contain a large amount of nitrogen, phosphorus and other substances, while the environmental problems caused by arbitrary discharge. This work explored the effects of temperature, reaction time and solid-liquid ratio on the chemistry of HLPs of two different distillers grains, with a focus on nutrient composition. Increased HTT temperature was related to increased HLPs pH, dissolved organic carbon content, and aromaticity, and decreased electrical conductivity. Maximum nutrient extraction efficiencies observed for NH4+-N, NO3--N and PO43- were 92.0, 89.9, and 94.3%, respectively. Response surface methodology showed that the release of nutrient extraction efficiency was the greatest at the hydrothermal treatment of 200 °C for 1 h, and using a solid/liquid ratio of 10%. Comparative studies, the nutritional value of HLPs are appropriate for use as an agricultural fertilizer, and its use as a substitute for synthetic fertilizers could increase the sustainability and profitability of farming.

Effects of physical preparation of diets and inclusion rate of modified wet distillers grains with solubles on production and rumen measurements of lactating dairy cows.

Our objective was to determine if methods for preparing total mixed ration [TMR; horizontal paddle mixer with knives (PK) vs. vertical auger (VA) mixer] would alter the physical form of the TMR and affect utilization of diets with increasing amounts of modified wet distillers grains with solubles (MWDGS). Holstein cows (n = 24 with 12 ruminally cannulated; 144 d in milk ± 31 d at start) were used in a split-plot design with mixer type as the whole plot and MWDGS concentrations as subplots in a replicated 3 × 3 Latin square arrangement with 35-d periods. Inclusion rates of MWDGS were 10, 20, and 30% of dietary dry matter, primarily replacing corn, soybean meal, soyhulls, and whole cottonseed. Feed dry matter intake (DMI) was less for PK (23.8 kg/d) than for VA (25.7 kg/d), but was unaffected by MWDGS concentration. Milk production did not differ by concentration of MWDGS or by interaction of MWDGS × mixer. Milk fat percentage declined with increasing MWDGS but the interaction between mixer and MWDGS showed that decreases were larger with VA mixing. Cows fed the diet containing 30% MWDGS mixed with PK averaged 3.45% (1.24 kg/d) milk fat, whereas cows fed the same diet mixed with VA averaged 2.81% (1.10 kg/d) fat. Concentrations of trans-10,cis-12 C18:2 in milk fat likely explain the differences observed in milk fat yield; the concentration of trans-10,cis-12 C18:2 increased as MWDGS was increased and the MWDGS × mixer interaction showed that VA had greater concentrations. Greater mean particle size and increased variation in particle size with VA may partially explain differences in milk fat via increased sorting that allowed for an altered rumen environment and favored alternative biohydrogenation pathways. Feed conversion efficiency (FCE; energy-corrected milk/DMI) decreased linearly as MWDGS increased, but FCE tended to be maintained when higher MWDGS diets were mixed using PK rather than VA. Ruminal pH and ammonia concentration decreased linearly as MWDGS increased. The PK mixer resulted in greater FCE when higher amounts of MWDGS were fed, primarily because milk fat content and yield were not as depressed and DMI was lower at similar milk yields.

Production performance and nitrogen metabolism in dairy cows fed supplemental blends of rumen undegradable protein and rumen-protected amino acids in low- compared with high-protein diets containing corn distillers grains.

Feeding corn dried distillers grains with solubles (DDGS) in low crude protein (CP) diets could limit N waste in lactating cows. However, it also could possibly reduce metabolizable AA supply, especially Lys, and compromise milk production. Therefore, the objective of this study was to evaluate the effects of feeding supplemental blends of rumen undegradable protein (RUP) and rumen-protected (RP) AA in a low compared with high CP diet containing corn DDGS on milk production and selected measures of N utilization. Six multiparous Holstein cows (619.3 ± 49.8 kg of body weight; 26.8 ± 6.2 d in milk) were subjected to a split-plot, 3 × 3 Latin square design (21-d periods) with dietary CP content [low (14.6%; LP) or high (16.6%; HP)] as the whole-plot factor, and blend of RUP and RP-AA [control (CON), no supplement; blend A (0.11 kg/cow per d); or blend B (0.45 kg/cow per d)] as the sub-plot factor. All diets contained 10% corn DDGS; blends of RUP and RP-AA were top-dressed during morning feeding. There was no dietary CP content × supplemental blend interaction for all measured variables. Nutrient (dry matter, organic matter, neutral detergent fiber, acid detergent fiber, and CP), milk and milk component yields, and feed and apparent N efficiency did not differ for cows fed the low- compared with the high-protein diet. However, apparent total-tract CP digestibility, blood and milk urea-N concentrations, and urinary excretion (g/d) of N and urea-N were lower for cows fed the low-protein compared with the high-protein diet. There was no supplemental blend effect on nutrient intake and apparent total-tract digestibility, and milk and milk component yields. Except for a tendency for total urinary purine derivative excretion and microbial N flow to be lower for cows fed blend B compared with CON but not blend A, there was no supplemental blend effect on measures of N utilization. Both dietary CP content and supplemental blend of RUP and RP-AA had a marginal effect on the plasma free AA profile. In summary, reducing dietary CP content in diets containing corn DDGS had no effect on lactation performance, possibly accounting for the lack of a positive response following the provision of supplemental blends of RUP and RP-AA. However, reducing dietary CP content resulted in a decrease in blood and milk urea-N concentrations, and urinary excretion of N and urea-N, suggestive of an improvement in the efficiency of N use.

Feeding a diet with corn distillers grain with solubles to dairy cows alters manure characteristics and ammonia and hydrogen sulfide emissions from manure.

The objective of the experiment was to examine effects of a diet containing a high concentration (28.8% dry matter basis) of corn distillers grain with solubles on manure characteristics and NH3 and H2S emissions from dairy cow manure. Eighteen cows were blocked by parity and days in milk, and cows in each block were assigned to the following treatments: the control diet (CON) or CON with distillers grains with solubles at 28.8% (dry matter basis) replacing mainly soybean meal (DG). The experiment was conducted for 11 wk, and feces and urine from individual cows were collected over 3 d in wk 11 (a total of 8 spot samples per cow). Fecal or urine samples were composited by cow, and the composite feces and urine were analyzed for indigestible neutral detergent fiber and creatinine concentration, respectively, for individual cows to estimate total fecal and urine outputs. Immediately before the manure incubation, composited feces and urine were sampled to determine manure characteristics. Manure was reconstituted according to daily fecal and urine excretion estimated for individual cows. Individual manures were incubated using a continuous air flux multichamber system over 10 d to measure NH3 and H2S emissions. All data from 18 manures were analyzed using the Mixed procedure of SAS (SAS Institute Inc., Cary, NC). The ratio of feces to urine and the contents of manure total and volatile solids were not different among treatments. Urine from DG had lower pH and DG manure had lower N content and greater S content compared with CON. During the 10-d incubation, NH3 emission was considerably less for DG versus CON. The emission of H2S over 10 d for DG was greater compared with that for CON. After the incubation, manure pH and N and S concentrations were greater for DG versus CON. In conclusion, manure from cows fed a high-DG diet decreased urinary N contribution to manure N and lowered urine pH, which were the factors that caused the decrease in NH3 emission from DG manure. However, the DG diet increased dietary S concentration and increased S excretion in urine and feces. This increased H2S emission from DG manure during the 10-d manure incubation.

Effects of agroindustrial by-product supplementation on dairy goat milk characteristics, nutrient utilization, ruminal fermentation, and methane production.

The use of agroindustrial by-products, such as dried distillers grains with solubles (DDGS) and dried citrus pulp (DCP), has been widely investigated in dairy cows, but information on their effects in dairy goats is limited. The influence of feeding olive cake (a by-product of olive oil production) to dairy goats has been assessed in some studies, but exhausted olive cake (EOC) has been much less investigated. Twelve Murciano-Granadina goats were used in a crossover design trial with 2 periods to assess the effects of including agroindustrial by-products on nutrient digestibility, ruminal fermentation, methane production, urinary excretion of purine derivatives, and milk yield and composition. In each period, 6 goats received daily a control diet comprising 1 kg of alfalfa hay and 1 kg of high-cereal concentrate, and another 6 goats received a diet (BYP) comprising 1 kg of alfalfa hay and 1 kg of a concentrate including corn DDGS, DCP, and EOC in proportions of 180, 180, and 80 g/kg of concentrate (as-fed basis), respectively. Diet had no effect on total dry matter intake, but intake of alfalfa hay, CP, and fat was greater for the BYP group than for the control group. There were no differences between diets in nutrient apparent digestibility, with the exception of fat, which was greater for the BYP diet compared with the control diet. Although fecal N tended to be greater for the BYP diet, there were no differences in N utilization. Compared with the control diet, milk yield tended to be greater and daily production of milk CP, fat, whey protein, and TS as well as milk gross energy were greater for the BYP diet. The concentration of C12:0, C14:0, and C16:0 fatty acids (FA) was or tended to be lower and the concentration of polyunsaturated FA was greater in the milk of BYP-fed goats compared with goats fed the control diet. Diet had no effect on ruminal parameters (pH, volatile FA, and NH3-N concentrations) and methane emissions, but urinary excretion of total purine derivatives tended to be lower in BYP-fed goats than in those fed the control diet. A mixture of corn DDGS (180 g), DCP (180 g), and EOC (80 g) could replace 44% of cereal grains and protein feeds in the concentrate for dairy goats without compromising nutrient utilization, ruminal fermentation, or milk yield and led to a more unsaturated FA profile in milk.

Reducing methane production with corn oil and calcium sulfate: Responses on whole-animal energy and nitrogen balance in dairy cattle.

The addition of fat and calcium sulfate to diets fed to ruminants has resulted in a reduction in methane production, but the effects on energy balance have not been studied. A study using indirect calorimetry and 16 multiparous (8 Holstein and 8 Jersey; 78 ± 15 d in milk; mean ± standard deviation) lactating dairy cows was conducted to determine how mitigating methane production by adding corn oil or calcium sulfate to diets containing reduced-fat distillers grains affects energy and nitrogen balance. A replicated 4 × 4 Latin square design with 35-d periods (28 d of adaption and 4 d of collections) was used to compare 4 different dietary treatments. Treatments were composed of a control (CON) diet, which did not contain reduced-fat distillers grain and solubles (DDGS), and treatment diets containing 20% (dry matter basis) DDGS (DG), 20% DDGS with 1.38% (dry matter basis) added corn oil (CO), and 20% DDGS with 0.93% (dry matter basis) added calcium sulfate (CaS). Compared with CON, dry matter intake was not affected by treatment, averaging 29.6 ± 0.67 kg/d. Milk production was increased for diets containing DDGS compared with CON (26.3 vs. 27.8 ± 0.47 kg/d for CON vs. DDGS, respectively), likely supported by increased energy intake. Compared with CON, energy-corrected milk was greater in DG and CO (30.1 vs. 31.4, 31.7, and 31.0 ± 0.67 kg/d for CON, DG, CO, and CaS, respectively). Compared with CON, the addition of calcium sulfate and corn oil to diets containing DDGS reduced methane production per kg of dry matter intake (22.3, 19.9, and 19.6 ± 0.75 L/kg per d for CON, CO, and CaS, respectively). Similarly, methane production per kilogram of energy-corrected milk was reduced with the addition of calcium sulfate and corn oil to diets containing DDGS (14.2, 12.5, and 12.4 ± 0.50 L/kg per d for CON, CO, and CaS, respectively). Compared with CON and CaS, the intake of digestible energy was greater for DG and CO treatments (57.7, 62.1, 62.0, and 59.0 ± 1.38 Mcal/d for CON, DG, CO, and CaS, respectively). Intake of metabolizable energy was greater in all treatments containing DDGS compared with CON (50.5 vs. 54.0 ± 1.08 Mcal/d for CON vs. DDGS, respectively). Net balance (milk plus tissue energy) per unit of dry matter was greater in CO (containing DDGS and oil) than CON (1.55 vs. 1.35 ± 0.06 Mcal/kg for CO vs. CON, respectively). Tissue energy was greater in DG and CO compared with CON (6.08, 7.04, and 3.16 ± 0.99 Mcal/d for DG, CO, and CON, respectively. Results of this study suggest that the addition of oil and calcium sulfate to diets containing DDGS may be a viable option to reduce methane production and in the case of oil also improve net energy balance in lactating dairy cows.

Growth performance, rumen fermentation, nutrient utilization, and metabolic profile of dairy heifers limit-fed distillers dried grains with ad libitum forage.

The objective of this study was to determine the effects of feeding a corn- and soybean-product-based concentrate mix or distillers dried grains with solubles concentrate mix with ad libitum grass hay to dairy heifers. A 16-wk randomized complete block design study was conducted using 24 heifers [18 Holstein and 6 Brown Swiss; 219 ± 2 d of age (±standard deviation); 230 ± 4 kg of body weight] to evaluate the effect of diet on dry matter intake (DMI), growth performance, rumen fermentation, metabolic profile, and nutrient digestibility. Treatments were (1) corn and soybean product concentrate mix, and (2) distillers-dried-grains-with-solubles-based concentrate mix (DDG). Both concentrate mixes were limit-fed at 0.8% of body weight and grass hay was offered ad libitum. Heifers were individually fed using Calan gates and orts were recorded daily at feeding. Heifers were weighed every 2 wk and ration concentrate mix offered was adjusted accordingly. Frame measurements and body condition score were recorded every 2 wk. Rumen fluid was collected via esophageal tubing during wk 12 and 16 for pH, ammonia N, and volatile fatty acid analysis. Jugular blood samples were collected every 4 wk for metabolite and metabolic hormone analysis. Total-tract digestibility of nutrients was evaluated during wk 16 by fecal grab sampling. No treatment by week interactions were observed for any of the growth measurements and growth measurements and DMI did not differ between treatments. A treatment by time interaction was observed for rumen butyrate percentage with heifers fed DDG having a greater percentage. Total volatile fatty acid concentration, acetate molar percentage, and acetate:propionate decreased with the DDG treatment, whereas propionate molar percentage increased. No treatment by week interactions were observed for any of the metabolites or metabolic hormones measured. A tendency was observed for glucose and plasma urea nitrogen concentration to decrease with DDG. Plasma cholesterol and insulin increased with DDG. Results demonstrated that limit-feeding heifers DDG at 0.8% of body weight with ad libitum grass hay maintained growth performance, average daily gain, DMI, and gain:feed, with shifts in the metabolic profile compared with the corn and soybean product concentrate mix.

Effects of corn feeding reduced-fat distillers grains with or without monensin on nitrogen, phosphorus, and sulfur utilization and excretion in dairy cows.

This study investigated effects of high inclusion of reduced-fat corn distillers grains with solubles (RFDG) with or without monensin on utilization and excretion of dietary N, P, and S. The experiment was conducted for 11 wk (2-wk diet adaptation, 9-wk experimental period of data collection) with 36 Holstein cows in a randomized complete block design. Cows were blocked by parity, days in milk, and milk yield and assigned to the following diets: (1) a control diet (CON); (2) CON with RFDG included at 28.8% (dry matter basis) by replacing soybean meal, soyhulls, and supplemental fat and phosphorus (DG); and (3) DG with monensin (Rumensin; Elanco Animal Health, Greenfield, IN) supplemented at a rate of 20 mg/kg of DM offered (DGMon). Contrasts were used to compare CON versus DG and DG versus DGMon. Inclusion of RFDG at 28.8% of dietary DM replacing mainly soybean meal did not change crude protein content (17.6% on a DM basis) but decreased rumen-degradable protein and increased rumen-undegradable protein. In addition, the DG diets increased P (0.48 vs. 0.36%) and S concentrations (0.41 vs. 0.21%; DM basis) compared with the CON diet. As a result, DG versus CON decreased plasma and milk urea N concentrations and urinary N excretion. However, the increase in P concentration when feeding the DG versus CON diet to lactating cows increased P intake, plasma P concentration, and urinary and fecal P excretion without affecting milk P secretion. Intake of S was greater for cows fed the DG versus CON diet, resulting in greater plasma total S and sulfate concentration and urinary and fecal S excretion. However, milk S secretion was not affected by DG compared with CON. Monensin supplementation to the DG diet did not affect N intake, utilization, and excretion except that apparent N digestibility was lower compared with DG. In addition, feeding the DGMon diet did not affect P and S utilization and excretion compared with DG. The study suggests that inclusion of high RFDG in a ration by replacing mainly soybean meal altered N, P, and S utilization and excretion, but monensin supplementation to a high-RFDG diet, overall, had minimal effects on N, P, and S utilization and excretion in lactating dairy cows.

Feeding reduced-fat dried distillers grains with solubles to lactating Holstein dairy cows does not alter milk composition or cause late blowing in cheese.

Feeding dried distillers grains with solubles (DDGS) to lactating dairy cows has been implicated as a cause of late blowing defects in the production of Swiss-style cheeses. Our objectives were (1) to test the effect of feeding reduced-fat DDGS (RF-DDGS; ∼6% fat) to lactating dairy cows on the composition of milk and on the suitability of the milk for production of baby Swiss cheese and (2) to evaluate the effect of diet on cow lactation performance. Lactating Holstein dairy cows were fed both dietary treatments in a 2 × 2 crossover design. Cows were housed in a 48-cow freestall pen equipped with individual feeding gates to record feed intake. The control diet was a corn, corn silage, and alfalfa hay diet supplemented with mechanically expelled soybean meal. The experimental diet was the same base ration, but 20% (dry matter basis) RF-DDGS were included in place of the expelled soybean meal. The RF-DDGS diet was additionally supplemented with rumen-protected lysine; diets were formulated to be isoenergetic and isonitrogenous. Cows were allowed ad libitum access to feed and water, fed twice daily, and milked 3 times daily. For cheese production, milk was collected and pooled 6 times for each dietary treatment. There was no treatment effect on milk yield (35.66 and 35.39 kg/d), milk fat production (1.27 and 1.25 kg/d), milk fat percentage (3.65 and 3.61%), milk protein production (1.05 and 1.08 kg/d), lactose percentage (4.62 and 4.64%), milk total solids (12.19 and 12.28%), and somatic cell count (232.57 and 287.22 × 103 cells/mL) for control and RF-DDGS, respectively. However, dry matter intake was increased by treatment, which implied a reduction in feed efficiency. Milk protein percentage also increased (3.01 and 3.11%), whereas milk urea nitrogen decreased (14.18 and 12.99 mg/dL), indicating that protein utilization may be more efficient when cows are fed RF-DDGS. No differences in cheese were observed by a trained panel except cheese appearance; control cheese eyes were significantly, but not practically, larger than the RF-DDGS cheese. These results indicate that RF-DDGS can be effectively used in the rations of lactating Holstein cows with no deleterious effects on milk production and composition and metrics of the physiology of the cow (i.e., blood glucose and nonesterified fatty acids); however, feeding RF-DDGS increased dry matter intake, which decreased feed efficiency. Finally, feeding RF-DDGS did not negatively influence quality and suitability of milk for production of baby Swiss cheese.

Continuous 11-week feeding of reduced-fat distillers grains with and without monensin reduces lactation performance of dairy cows.

This study investigated the effects of continuous feeding of high inclusion of reduced-fat corn distillers grains with solubles with and without monensin on dry matter intake (DMI), production, milk fatty acid profile, and plasma AA profile in lactating cows. The experiment was conducted for 12 wk (1-wk covariate, 2-wk diet adaptation, and 9-wk experimental period of data collection) with 36 Holstein cows in a randomized complete block design. Cows were blocked by parity, days in milk, and milk yield and assigned to the following diets: (1) control (CON), (2) CON with reduced-fat corn distillers grains with solubles included at 28.8% (dry matter basis) replacing soybean meal, soyhulls, and supplemental fat (DG), and (3) DG with monensin (Rumensin; Elanco Animal Health, Greenfield, IN) supplemented at a rate of 20 mg/kg of DM offered (DGMon). Orthogonal contrasts were used to compare CON versus DG and DGMon and to compare DG versus DGMon. Milk yield was not affected (40.3 vs. 40.8 kg/d) by DG and DGMon compared with CON. However, for DG and DGMon compared with CON, decreased DMI (24.9 vs. 26.4 kg/d), milk fat yield (1.12 vs. 1.55 kg/d), milk protein yield (1.24 vs. 1.32 kg/d), and energy-corrected milk yield (37.7 vs. 43.5 kg/d) were observed. Feeding DGMon compared with DG did not affect DMI (24.4 vs. 25.4 kg/d) and milk yield (39.2 vs. 41.3 kg/d) but decreased milk fat yield (1.08 vs. 1.23 kg/d), milk protein yield (1.20 vs. 1.28 kg/d), and energy-corrected milk yield (36.0 vs. 39.4 kg/d). Interactions between treatment and week for DMI, milk fat yield, and energy-corrected milk indicate that production responses to DG and DGMon versus CON were decreased over the experimental period. Cows fed DG and DGMon had increased milk fat concentration of trans-10,cis-12 18:2, trans-10 18:1, and long-chain (>16C) and polyunsaturated fatty acids and decreased short-chain (<16C) and odd- and branched-chain fatty acids compared with CON. No difference was observed between DG and DGMon in milk fatty acid profile. In the current study, feeding a high-DG diet did not sustain DMI and production, and supplementing monensin to a high-DG diet further decreased DMI and production.

Corn-Based Distillers' Grains in Diets for Feedlot Cattle Are Associated with the Burden of Escherichia coli O157 in Feces.

Inclusion of distillers' grains (DGs) has been associated with increased prevalence of Escherichia coli O157:H7 in cattle housed in research settings. Our objective was to quantify the relationship between inclusion of DGs in commercial feedlot rations and the burden of E. coli O157. A convenience sample of 10 feedlots was enrolled based on DG use in finishing diets; 1 cohort included 5 feedlots in which DGs were greater than 15% of the dietary dry matter and the other cohort consisted of 5 feedlots at a concentration less than 8%. Sampling occurred at each feedlot on four occasions at ∼6-week intervals. At each feedlot visit, 4 pens of cattle within 3 weeks of slaughter were selected and 24 freshly voided fecal pats were sampled. Ten-gram samples were enriched in 90 mL of modified tryptic soy broth with novobiocin (20 mg/L) for 14 h at 42°C. Enrichments were subjected to immunomagnetic separation, plating onto chromogenic agar with novobiocin (5 mg/L) and potassium tellurite (2.5 mg/L), incubation for 18 h at 37°C, and latex agglutination of morphologically typical colonies. E. coli O157 was recovered from 16.7% of 3840 samples. Adjusted prevalence was 14.3% after controlling for within-feedlot and within-pen clustering. Prevalence during each sampling period was 19.9% (round 1), 21.0% (round 2), 14.1% (round 3), and 11.7% (round 4). Prevalence varied between cohorts, but this difference varied over time (p = 0.06). Among those with greater than 15% of the diet as DGs, prevalence was greater than those with less than 8% inclusion for all rounds of sampling (p < 0.01). Averaged across time, prevalence was 23.9% and 9.4% for those with greater than 15% and those with less than 8% of DGs, respectively. While observational, these data provide real-world support of reports of increased E. coli O157:H7 burden associated with DG use in cattle diets.

Effect of dried corn distillers' grains with solubles and soybean meal supplements on physiological indicators and reproductive performance of ewes.

This study aimed to evaluate the effects of adding dried distillers' grains with solubles (DDGS) to the nutritional regimens of ewes at different time periods on reproductive traits, serum hormones and serum metabolites. In Experiment 1, 100 ewes were divided into 4 groups (n = 25) according to diet. The four diets were grass hay (H) alone (group H), H with barley (group H + B), H with DDGS for the whole feeding period (27 d) (group H + DDGS) or H and DDGS for 5 d (d 8-12 of oestrus cycle) (group H + DDGS5). Serum progesterone concentrations were affected by oestrus cycle (p < 0.001), but not by dietary treatments. However, feeding H + DDGS caused significant increases in serum insulin, leptin and growth hormone concentrations (p < 0.05). In Experiment 2, 30 ewes were divided into 2 groups (n = 15), receiving DDGS or soybean meal (SBM) during the prepartum period. Diets had no significant effect on weights of dams or lambs at birth; however, the weaning weights of lambs born from ewes of group DDGS were significantly higher (p < 0.05). Moreover, serum glucose, blood urea nitrogen, triglyceride and beta hydroxybutyric acid (BHBA) concentrations during the prepartum period were affected by dietary treatments and by time (p < 0.001). During the prepartum period, BHBA concentrations of ewes fed SBM were higher, while BHBA levels decreased during the last weeks of pregnancy regardless of diet. Lamb serum immunoglobulin G concentrations increased from 1 h to 24 h after birth (p < 0.001). Colostrum of ewes fed SBM had higher fat-free dry matter (DM) and protein contents in comparison to colostrum of ewes fed DDGS (p < 0.05). In conclusion, DDGS can be included as protein source in pregnancy rations up to 15% of DM to obtain reproductive performance outcomes equal to or exceeding those obtained with SBM.

Nutrient availability of different batches of wheat distiller's dried grains with solubles for turkeys.

Effects of five different batches of wheat distiller's dried grains with solubles (DDGS) were used to investigate bioavailability of energy and nutrients for turkeys. The laboratory analysis of the DDGS showed the largest variations for soluble non-starch polysaccharides, oil and ash. In total, 96 birds were fed one of six mash diets. The basal diet contained per kilogram 535 g wheat and 300 g soya bean meal, corresponding to 247 g crude protein and 12.6 MJ N-corrected apparent metabolisable energy (AMEn). Another five diets contained per kilogram 200 g of each DDGS samples in replacement for basal diet. Each diet was fed to eight pens with two female Premium turkeys following randomisation. The AMEn and the nutrient retention coefficients of the pure DDGS samples were obtained using the substitution method. The AMEn of the DDGS from batch A was higher (p = 0.048) compared to those from batches B and C, but did not differ from DDGS samples D and E. There were no differences in dry matter retention, nitrogen retention and fat digestibility between the DDGS samples tested. The AMEn of the DDGS samples correlated positively (p < 0.05) to the starch (r = 0.895) and the non-soluble non-starch polysaccharides contents (r = 0.940), and the red index of lighting (a) (r = 0.916), respectively. In general, findings from this study indicate bioavailability of energy and most nutrients to be in the range of published data with turkeys, and to vary between batches.

Bioconversion of distillers' grains hydrolysates to advanced biofuels by an Escherichia coli co-culture.

BACKGROUND: First generation bioethanol production utilizes the starch fraction of maize, which accounts for approximately 60% of the ash-free dry weight of the grain. Scale-up of this technology for fuels applications has resulted in a massive supply of distillers' grains with solubles (DGS) coproduct, which is rich in cellulosic polysaccharides and protein. It was surmised that DGS would be rapidly adopted for animal feed applications, however, this has not been observed based on inconsistency of the product stream and other logistics-related risks, especially toxigenic contaminants. Therefore, efficient valorization of DGS for production of petroleum displacing products will significantly improve the techno-economic feasibility and net energy return of the established starch bioethanol process. In this study, we demonstrate 'one-pot' bioconversion of the protein and carbohydrate fractions of a DGS hydrolysate into C4 and C5 fusel alcohols through development of a microbial consortium incorporating two engineered Escherichia coli biocatalyst strains. RESULTS: The carbohydrate conversion strain E. coli BLF2 was constructed from the wild type E. coli strain B and showed improved capability to produce fusel alcohols from hexose and pentose sugars. Up to 12 g/L fusel alcohols was produced from glucose or xylose synthetic medium by E. coli BLF2. The second strain, E. coli AY3, was dedicated for utilization of proteins in the hydrolysates to produce mixed C4 and C5 alcohols. To maximize conversion yield by the co-culture, the inoculation ratio between the two strains was optimized. The co-culture with an inoculation ratio of 1:1.5 of E. coli BLF2 and AY3 achieved the highest total fusel alcohol titer of up to 10.3 g/L from DGS hydrolysates. The engineered E. coli co-culture system was shown to be similarly applicable for biofuel production from other biomass sources, including algae hydrolysates. Furthermore, the co-culture population dynamics revealed by quantitative PCR analysis indicated that despite the growth rate difference between the two strains, co-culturing didn't compromise the growth of each strain. The q-PCR analysis also demonstrated that fermentation with an appropriate initial inoculation ratio of the two strains was important to achieve a balanced co-culture population which resulted in higher total fuel titer. CONCLUSIONS: The efficient conversion of DGS hydrolysates into fusel alcohols will significantly improve the feasibility of the first generation bioethanol process. The integrated carbohydrate and protein conversion platform developed here is applicable for the bioconversion of a variety of biomass feedstocks rich in sugars and proteins.

The effect of regular or reduced-fat distillers grains with solubles on rumen methanogenesis and the rumen bacterial community.

AIMS: The effect of feeding dried distillers grains with solubles (DDGS) or reduced-fat DDGS (RFDG) on ruminal methanogenesis and the rumen bacterial community of dairy cattle was evaluated. METHODS AND RESULTS: Treatments were CONT, a diet with no distillers grains; DG, inclusion of 20% DDGS; rfDG, inclusion of 20% RFDG; and MIX, inclusion of 10% DDGS and 10% RFDG. Methane emission was measured; rumen bacterial community was evaluated by sequencing the V4 region of the 16S rRNA gene. Total methane production remained unaffected. However, feeding distillers grains tended to reduce methanogenesis per unit of feed intake, decreased the abundance of the phylum Bacteroidetes and tended to increase Firmicutes. The abundance of Prevotellaceae positively correlated with feed intake; methane emission was positively correlated with the abundance of Prevotellaceae and was negatively correlated with the abundance of Succinivibrionaceae. CONCLUSIONS: DDGS or RFDG may reduce methanogenesis per unit of feed intake; shifts in the abundance of predominant ruminal bacterial families may influence methane formation, likely because of their role on hydrogen liberation and utilization pathways. SIGNIFICANCE AND IMPACT OF THE STUDY: Replacing corn and soybean meal with DDGS or RFDG in dairy rations may reduce the proportion of dietary energy wasted as methane, without detrimental effects on the overall bacterial population.

Feeding distillers dried grains in replacement of forage in limit-fed dairy heifer rations: Effects on metabolic profile and onset of puberty.

The objective of this study was to determine the effect of increasing the inclusion rate of distillers dried grains (DDGS) in replacement of forage in limit-fed diets on the metabolic profile and onset of puberty in dairy heifers. A 16-wk randomized complete block design study was conducted using 48 Holstein heifers (199 ± 2 d of age) with 3 treatments. Treatments were (1) 30% DDGS (30DG), (2) 40% DDGS (40DG), and (3) 50% DDGS (50DG), with the remainder of the diet consisting of grass hay and 1.5% mineral mix. Heifers were housed in groups of 6 and individually limit-fed using Calan gates at 2.65, 2.50, and 2.35% of body weight (BW) on a dry matter (DM) basis for 30DG, 40DG, and 50DG, respectively. Jugular blood samples were collected during wk 0, 4, 8, 12, and 16 for metabolite and metabolic hormone analysis. Additional samples were taken during wk 16 for plasma fatty acid analysis. When heifers weighed 200 kg, coccygeal vein blood samples were taken twice per week for progesterone analysis to estimate onset of puberty. Blood samples continued until cycling was confirmed via ultrasound for the presence of a corpus luteum. A quadratic response and a linear tendency in the proportion of total fatty acids as linoleic acid were observed. Linear and quadratic responses for plasma concentrations of linoleic acid and arachidonic acid occurred. Overall results for fatty acid analysis demonstrated that total fatty acid and polyunsaturated fatty acids concentration in the blood were linearly increased, with a quadratic response for polyunsaturated fatty acids with 30DG and 50DG having the greatest concentrations. No interactions of treatment by week were observed for any of the metabolites and metabolic hormones measured. Glucose, insulin, insulin-like growth factor-1, leptin, and triglycerides were similar across treatments. A linear response of plasma urea nitrogen and a quadratic response tendency for cholesterol concentration were observed. Age and BW at puberty were similar across treatments. Limit-feeding heifers with greater inclusion rates of DDGS maintained energy status without the accumulation of excess adipose tissue as indicated by leptin. Treatments had no detrimental effects on age or BW at puberty.

Short communication: Feeding distillers dried grains in replacement of forage in limit-fed dairy heifer rations: Effects on post-trial performance.

The objective of this study was to determine the effect of increasing the inclusion rate of distillers dried grains with solubles (DDGS) in replacement of forage in diets that were limit-fed during peripubertal growth on performance during the first 3 mo of first lactation. A secondary objective was to also characterize reproductive performance of the dairy heifers. A 16-wk randomized complete block design study was conducted using 48 Holstein heifers (199 ± 2 d of age) with 3 treatments. Treatments were (1) 30% DDGS, (2) 40% DDGS, and (3) 50% DDGS, with the remainder of the diet consisting of grass hay and 1.5% mineral mix. Heifers were individually limit-fed using Calan gates at 2.65, 2.50, and 2.35% of body weight on a dry matter basis for 30, 40, and 50% DDGS, respectively. After completing the feeding study, heifers were fed a common diet according to standard herd management. Data on reproductive performance and milk production for the first 3 mo of lactation were collected for each heifer from dairy herd records. At 3 wk prepartum and at calving, body weight, frame measurements, and body condition score were recorded. We found no differences in reproductive or frame measurements taken around parturition. However, due to relatively small numbers of heifers for evaluation of reproductive parameters, results should be viewed as qualitative rather than conclusive, and more research is necessary. We noted a treatment by month effect for somatic cell count; however, there were no other differences for any of the lactation parameters measured. Results demonstrate that up to 50% of diet can be fed in limit-fed rations as DDGS, compared with 30 or 40%, to peripubertal dairy heifers without negative consequences to first-lactation performance during the first 3 mo.

Effect of substituting soybean meal and canola cake with dried distillers grains with solubles at 2 dietary crude protein levels on feed intake, milk production, and milk quality in dairy cows.

Dried distillers grain with solubles (DDGS) is an alternative source of feed protein for dairy cows. Previous studies found that DDGS, based on grains other than corn, can substitute for soybean meal and canola cake as a dietary protein source without reducing milk production or quality. As societal concerns exist, and in many areas strict regulation, regarding nitrogen excretion from dairy cows, the dairy industry has focused on reducing dietary protein level and nitrogen excretion. In the present study, we investigated the use of DDGS as a protein source, at a marginally low dietary crude protein (CP) levels, in a grass-clover and corn silage-based ration. The experiment involved 24 Holstein cows and 2 protein sources (DDGS or soybean-canola mixture) fed at 2 levels of CP (14 or 16%) in a 4 × 4 Latin square design. The aim of this study was to evaluate the effect of both protein source and protein level on feed intake, milk yield, and milk quality. The results indicated that feed intake, milk yield, and protein in milk increased when the protein level in the ration was 16% CP compared with 14%. We found no effect of substituting the soybean-canola mixture with DDGS. Moreover, no sensory problems were observed when comparing fresh milk with stored milk, and milk taste was unaffected by DDGS. Milk from cows fed DDGS had a slightly higher content of linoleic acid and conjugated linoleic acid (CLA 9-11), and lower content of C11 to C17 fatty acids than cows fed diets with the soybean-canola mixture. Cows fed the diets with 16% CP produced milk with higher oleic acids and lower palmitic acid content than cows fed 14% CP diets. To conclude, DDGS can substitute for a soybean-canola mixture without affecting feed intake, milk yield and quality, or sensory quality. Under the conditions of this experiment, feeding 16% CP compared with 14% CP in the ration can increase feed intake and milk production.

Effect of substituting soybean meal and canola cake with grain-based dried distillers grains with solubles as a protein source on feed intake, milk production, and milk quality in dairy cows.

The growth of the bioethanol industry is leading to an increase in the production of coproducts such as dried distillers grains with solubles (DDGS). Both corn-based DDGS and grain-based DDGS (gDDGS; defined as originating from grain sources such as barley, wheat, triticale, or a mix, excluding corn) appear to be relevant sources of feed and protein for dairy cows. To date, most of the studies investigating DDGS have been performed with corn-based DDGS. The objectives of this study were to determine the effects of the proportion of gDDGS in the diet on feed intake, milk production, and milk quality. The present experiment involved 48 Holstein cows in a replicated 3 × 3 Latin square design with 3 grass-based dietary treatments consisting of 4, 13.5, and 23% gDDGS on a dry matter (DM) basis (L, M, and H, respectively) as a replacement for a concentrate mix. The concentrate mix consisted of soybean meal, canola cake, and beet pulp. Dry matter intake and energy-corrected milk yield were not affected by the proportion of gDDGS in the diet. Daily milk yield decreased with the H diet compared with the L and M diets. The percentage of fat in milk was higher when cows were fed the H diet compared with the L and M diets, whereas milk fat yield was not affected by dietary treatment. The M diet had a higher percentage of protein in milk compared with the L and H diets. Milk protein yield was similar for the L and M diets; however, it decreased for the H diet. Milk taste was not affected by the proportion of gDDGS in the diet or when milk was stored for 7 d. Linoleic acid and conjugated linoleic acid cis-9,trans-11 in milk increased with increasing proportion of gDDGS. To conclude, gDDGS can replace soybean meal and canola cake as a protein source in the diet of dairy cows. Up to 13.5% of the diet may consist of gDDGS without negatively affecting milk production, milk quality, or milk taste. When gDDGS represents 23% of dietary DM, milk production is reduced by 1.6 kg/d, whereas energy-corrected milk production is numerically reduced by 1 kg.