NDF Disappearance Research Articles

Effect of concentrate level on enteric methane emissions, production performance, and rumen fermentation of Jersey cows grazing kikuyu-dominant pasture during summer

The effect of concentrate feeding level on enteric CH4 emissions from cows grazing medium quality summer pasture is yet to be investigated. Sixty multiparous Jersey cows (9 rumen-cannulated) were used in a randomized complete block design study (with the cannulated cows in a 3 × 3 Latin square design) to investigate the effect of concentrate feeding level (0, 4, and 8 kg/cow per day; as-fed basis) on enteric CH4 emissions, production performance, and rumen fermentation of dairy cows grazing summer pasture (17 cows plus 3 cannulated cows per treatment). Enteric CH4 emissions were measured from 11 cows per treatment group during one 7-d measurement period using the sulfur hexafluoride tracer gas technique. Pasture dry matter intake (DMI) was determined parallel with the CH4 measurement period using TiO2 as an external marker, and milk yield, milk composition, cow condition, and pasture pre- and postgrazing measurements were also recorded. Daily total DMI (11.2 to 15.6 kg/cow), milk yield (9.1 to 18.2 kg/cow), energy-corrected milk (ECM; 11.2 to 21.6 kg/cow), and milk lactose content (44.1 to 46.7 g/kg) increased linearly, whereas pasture DMI (11.2 to 8.4 kg/cow) decreased linearly with increasing concentrate feeding level. Daily CH4 production (323 to 378 g/d) increased linearly due to the increase in total DMI, whereas CH4 yield (29.1 to 25.1 g/kg of DMI) and CH4 intensity (35.5 to 21.1 g/kg of milk yield; and 28.8 to 17.6 g/kg of ECM) decreased linearly with increasing concentrate feeding level. Diurnal ruminal pH (6.45 to 6.32) and in sacco DM and neutral detergent fiber disappearance decreased linearly. Acetic and propionic acid were unaffected by treatment, whereas butyric acid (5.21 to 6.14 mM) increased linearly and quadratically with increasing concentrate feeding level. It was concluded that a high concentrate feeding level not only increases animal efficiency but is moreover a viable CH4 mitigation option for dairy cows grazing kikuyu-dominant pasture in late summer when pasture is inherently fibrous.

Ruminal parameters and ruminal degradability of feedlot sheep fed safflower grains

SUMMARY This study aimed to evaluate the rumen degradability of dry matter (DM), disappearance of neutral detergent fiber (NDF) of Tifton 85 hay, and fermentation parameters (pH and ruminal ammonia nitrogen) of sheep fed diets with inclusion of safflower grains (0, 7.50 and 15%). Three mixed breed lambs with average body weight of 35.50± 1.50 kg were used. The rumen degradability of dry matter and NDF of the Tifton 85 haywas analyzedby the disappearance of DM and NDF, and the kinetic parameters adjusted according to the first order asymptotic model. The samples were incubated in the rumen in descending order (96, 48, 24, 12, 6, 3, 0 hours). The determination of ruminal pH and ruminal ammonia nitrogen (RAN) was performed before feeding and 2, 4, 6 and 8 hours after feeding. Data of ruminal fermentation were tested by analysis of variance with repeated measures in time, at 5% probability. Ruminal pH values were not statistically different. When evaluating the RAN, there was a significant difference between the times and treatments for the diet with 15% safflower. The diets presented low effective degradability of DM and NDF with mean values of 18.02% and 47.40%, respectively. The safflower grain can be used up to 7.50% in the diets without altering the degradability and ruminal fermentation.

Effect of dietary nitrate on enteric methane emissions, production performance and rumen fermentation of dairy cows grazing kikuyu-dominant pasture during summer

Dietary nitrate supplementation is an effective methane (CH4) mitigation strategy in total mixed ration based diets fed to ruminants. To date, limited information is available on the effect of dietary nitrate on CH4 production from grazing dairy cows. Fifty-four multiparous Jersey cows were subjected to a randomised complete block design (blocked according to milk yield, days in milk and parity) to evaluate the effect of three dietary nitrate levels on enteric CH4 emissions and cow production performance. Additionally, six rumen-cannulated cows in a replicated 3 × 3 Latin square design were used in a rumen study. Dietary treatments consisted of concentrate fed at 5.4 kg of DM/cow per day containing one of three levels of dietary nitrate: 0 g (control), 11 g (low nitrate), and 23 g of nitrate/kg of dry matter (DM; high nitrate). Cows grazed late-summer pasture containing approximately 3 g of nitrate/kg of DM. Concentrates were formulated to be isonitrogenous, by substituting urea, and isoenergetic. Cows were gradually adapted to concentrates over a 3-wk period before the onset of a 57-d experimental period. Enteric CH4 emissions and total dry matter intake (DMI) from 11 cows per treatment were measured during one 6-d measurement period using the sulphur hexafluoride tracer gas technique. Individual pasture DMI was determined using TiO2 and indigestible neutral detergent fibre (NDF). Milk yield decreased by approximately 12% when feeding the high nitrate diet compared with the control and low nitrate diets. Although total DMI was unaffected by treatment, concentrate DMI decreased linearly (5.5–3.7 kg/d) while pasture DMI increased linearly (9.1–11.4 kg/d) with increasing dietary nitrate addition. Methane production (313–280 g/d), CH4 yield (21.8–18.7 g/kg of DMI) and CH4 energy per gross energy intake (6.9–5.9%) tended to decrease linearly with increasing dietary nitrate addition. Diurnal ruminal pH of the high nitrate group was greater, for selective periods after concentrate feeding, than the control and low nitrate groups. Spot sample ruminal pH (6.2–6.3) tended to increase while total volatile fatty acid (VFA) concentration (99.9–104 mM/L) increased quadratically with increasing dietary nitrate addition. Individual VFA concentrations were unaffected by treatment. Rate of NDF disappearance (2.4–2.8%/h) after 18 h of ruminal incubation tended to increase quadratically with increasing dietary nitrate addition. Dietary nitrate fed to grazing dairy cows tended to decrease CH4 emissions while improving the fibrolytic environment of the rumen. However, when feeding high levels of dietary nitrate a decrease in milk yield could be expected due to a decrease in concentrate DMI.

Effects of growth stage and growing degree day accumulations on triticale forages: 2. In vitro disappearance of neutral detergent fiber

The use of winter triticale (X Triticosecale Wittmack) in dairy-cropping systems has expanded greatly in recent years, partly because of its value as a forage crop but also to improve land stewardship by providing winter ground cover. Our objectives were to use 2-pool and 3-pool nonlinear models to characterize in vitro disappearance of neutral detergent fiber (NDF) and then describe the relationship between estimated parameters from those models with plant growth stage or growing degree days (GDD) >5°C for winter triticale forages harvested during 2016 and 2017 in Marshfield, Wisconsin. Forages were harvested from replicated field plots each year at growth stages ranging from stem elongation to soft dough. All NDF analyses included use of sodium sulfite and heat-stable α-amylase with residual fiber corrected for contaminant ash (asNDFom). Nonlinear 3-pool models for in vitro disappearance of asNDFom that included fast (Bfast) and slow (Bslow) disappearance pools as well as an associated disappearance rate for each (Kdfast and Kdslow, respectively) were easily fitted provided that a single discrete lag time was applied to both Bfast and Bslow pools to reduce the number of parameters to be estimated. An unresolved issue related to fitting 3-pool decay models was the incomplete recovery of asNDFom from immature triticale forages at 0 h, which was partially resolved with 2 approaches that produced similar estimates of Kdfast and Kdslow. Most parameters obtained from 2- and 3-pool decay models for asNDFom could be related to growth stage or GDD using polynomial regression techniques, often with high coefficients of determination (R2). For 3-pool models of asNDFom disappearance, Bslow increased with plant maturity, but the associated Kdslow ranged narrowly from 0.011 to 0.015/h and could not be related to growth stage or GDD by quartic, cubic, quadratic, or linear regression models. Despite different cultivars coupled with substantial differences in precipitation across years, single endpoint estimates of in vitro disappearance of asNDFom after 24, 30, or 48 h of incubation were closely related (R2 ≥ 0.906) to growth stage and GDD by linear or quadratic regression models that were generally similar across production years. Typical recommendations for harvesting triticale at boot stage to facilitate the planting of a double crop are strongly supported by the extensive 30-h in vitro disappearance of asNDFom at that growth stage, which was 63.1 and 64.8% of asNDFom during 2016 and 2017, respectively.

New recombinant fibrolytic enzymes for improved in vitro ruminal fiber degradability of barley straw1.

This study used a high-throughput in vitro microassay, in vitro batch culture, and the Rumen Simulation Technique (RUSITEC) to screen recombinant fibrolytic enzymes for their ability to increase the ruminal fiber degradability of barley straw. Eleven different recombinant enzymes in combination with a crude mixture of rumen enzymes (50% recombinant enzyme:50% crude mixture of rumen enzymes) were compared with the crude mixture of rumen enzymes alone. In the microassay, all treatments were applied at 15 mg of protein load per gram barley straw glucan. Based on the microassay results, 1 recombinant endoglucanase [EGL7A, from the glycoside hydrolase (GH) family 7], 2 recombinant xylanases (XYL10A and XYL10C, from GH10), and a recombinant enzyme mixture were selected and compared with a crude mixture of fibrolytic enzymes from Aspergillus aculeatus for their ability to hydrolyze barley straw. For batch culture, enzymes were applied to barley straw at 2 dosages (100 and 500 µg of protein/g of substrate DM). All enzymes increased (P < 0.05) DM disappearance and total VFA production, but the mixture of recombinant enzymes was not superior to the use of a single recombinant enzyme. Based on positive results (P < 0.05) for total DM disappearance and VFA production in batch culture, 3 enzymes (EGL7A, XYL10A, and XYL10C) were selected and applied to barley straw at 500 µg of protein per gram for further assessment in RUSITECs fed a concentrate:barley straw diet (300:700 g/kg DM). In RUSITECs, the recombinant enzyme XYL10A increased (P < 0.05) barley straw DM, NDF, and ADF disappearance, whereas EGL7A and XYL10C had no effect. The enzymes selected based on the high-throughput in vitro microassay consistently increased barley straw degradation in ruminal batch culture, but not in the semicontinuous culture RUSITEC system.

Effect of engineered biocarbon on rumen fermentation, microbial protein synthesis, and methane production in an artificial rumen (RUSITEC) fed a high forage diet.

The objective of this study was to investigate the effects of adding engineered biocarbon to a high-forage diet on ruminal fermentation, nutrient digestion, and enteric methane (CH4) production in a semi-continuous culture artificial rumen system (RUSITEC). The experiment was a completely randomized block design with four treatments assigned to sixteen fermentation vessels (four/treatment) in two RUSITEC apparatuses. The basal diet consisted of 60% barley silage, 27% barley grain, 10% canola meal, and 3% supplement (DM basis) with biocarbon added at 0, 0.5, 1, and 2% of substrate DM. The study period was 17 d, with a 10-d adaptation and 7-d sample collection period. Increasing biocarbon linearly increased (P < 0.05) disappearance of DM, OM, CP, ADF and NDF. Compared to control, increasing biocarbon enhanced (P < 0.01) production of total VFA, acetate, propionate, branch-chained VFAs, and tended to increase (P = 0.06) NH3-N. Microbial protein synthesis linearly increased (P = 0.01) with increasing biocarbon. Addition of biocarbon reduced overall CH4 production compared with the control (P ≤ 0.05). There were no differences (P > 0.05) in production of total gas, large or small peptides, or in the number of protozoa as a result of addition of biocarbon to the diet. Addition of biocarbon to a forage diet increased DM digestibility by up to 2%, while lowering enteric CH4 production and enhancing microbial protein synthesis in in vitro semi- continuous culture fermenters.

Essential oils from Lippia turbinata and Tagetes minuta persistently reduce in vitro ruminal methane production in a continuous-culture system

The aim of the present study was to evaluate the impact of essential oils (EO) from Lippia turbinata (LT) and Tagetes minuta (TM) as well as the rotation of both EO on fermentation parameters in vitro. Daily addition of LT, TM, or a 3-day rotation between them (TM/LT), as well as a control (without EO), was evaluated using the rumen simulation technique (Rusitec). The experiment lasted 19 days, with a 7-day adaptation period, followed by 12 days of treatment (Days 0–12). The EO were dissolved in ethanol (70% vol/vol) to be added daily to fermenters (300 μL/L) from Day 0. Daily measurements included methane concentration, total gas production, apparent DM disappearance and pH, which started 2 days before the addition of treatments. On Days 0, 4, 8 and 12 apparent crude protein disappearance and neutral detergent fibre disappearance, ammonia and volatile fatty acid concentration and composition were determined. Methane production was significantly inhibited shortly after addition of both EO added individually, and persisted over time with no apparent adaptation to EO addition. The TM/LT treatment showed a similar effect on methane production, suggesting that rotating the EO did not bring further improvements in reduction or persistency compared with the inclusion of the EO individually. Gas production, total volatile fatty acid concentration and composition and apparent crude protein disappearance were not affected by EO addition. Compared with the control, a 5% reduction of apparent DM disappearance and a 15% reduction of neutral detergent fibre disappearance were observed with the addition of EO. Only TM and TM/LT reduced ammonia concentration. Given the significant and persistent antimethanogenic activity of both EO, and the potential of T. minuta to modify nitrogen metabolism, EO from these plant species are of interest for developing new feed additives with potential application in ruminant nutrition that are also likely to be acceptable to consumers.

Post-ruminal effects of rumen-protected methionine supplementation with low protein diet using long-term simulation and in vitro digestibility technique

Microbial degradation in the rumen and dietary availability of methionine amino acid have been reported as limiting in dairy ruminants. The aim of the present study was to examine the post-ruminal effects of feeding ruminants different concentrations of rumen-protected methionine (RPM) in low crude protein diets using the long-term rumen simulation method (Rusitec) followed by in vitro abomasum and ileum digestibility technique. The experiment contained four treatment groups: (1) high protein, without RPM supplementation (HP); (2) low protein, without RPM supplementation (LP); (3) low protein supplementation with low RPM (LPLM); and (4) low protein supplementation with high RPM (LPHM) mixed per 20 ± 0.04 g basal diet in every fermenter. The results showed that the LPLM and LPHM groups had significantly higher disappearance of crude protein and neutral detergent fiber in the abomasum and ileum than the HP treatment (P < 0.05) and were the same as the LP group (P > 0.05). The proportions of short-chain fatty acids and total volatile fatty acids in the abomasum and ileum were the same between the LPHM and HP groups (P > 0.05); however, the LPLM group was found to be significantly (P < 0.05) lower than the HP group and similar to the LP group (P > 0.05). Rusitec pH before or after changing feed bags and daily ammonia nitrogen production in the abomasum and ileum were non significantly (P > 0.05) different among all groups. In conclusion, RPM supplementation with low crude protein diets promoted post-ruminal digestibility and production of volatile fatty acids.

Effects of gallic acid on in vitro rumen fermentation and methane production using rumen simulation (Rusitec) and batch-culture techniques

Two experiments were conducted to investigate the effects of adding gallic acid (GA) to ruminant diets on long- and short-term in vitro rumen fermentation and methane (CH4) production, and to test possible interactions between GA and ethanol on fermentation. The first experiment was conducted using the rumen simulation technique (Rusitec), as a completely randomised block design with four replications and the following four doses of GA: 0, 5, 10 and 20 mg GA/g dry matter (DM). Ethanol was used in all treatments to increase the solubilisation of GA in rumen fluid. The experimental period lasted 16 days, of which the first 7 days were for adaptation and the subsequent 9 days were for sampling. The second experiment was a 48-h batch-culture incubation conducted as a completely randomised design with a 4 (GA dose; 0, 10, 20, and 40 mg GA/g DM) × 2 (with or without ethanol) arrangement of treatments. In the Rusitec experiment, addition of GA up to 20 mg/g DM did not affect DM disappearance (DMD), organic matter (OM) disappearance, neutral detergent-fibre disappearance (NDFD), acid detergent-fibre disappearance (ADFD) or starch disappearance (P &amp;gt; 0.05), but crude protein disappearance was linearly decreased (P = 0.04) from 78.3% to 72.0%. Daily gas production and CH4 production expressed as mL/g DM and mL/g DMD were not affected by addition of GA (P &amp;gt; 0.05). Addition of GA up to 20 mg/g DM increased butyrate and isovalerate production (P &amp;lt; 0.05) and tended to increase isobutyrate (P = 0.09) and decrease heptanoate production (P = 0.07). In the batch-culture experiment, adding GA up to 40 mg/g DM linearly increased 48-h DMD, NDFD and ADFD (P &amp;lt; 0.05) and decreased (P &amp;lt; 0.05) CH4 expressed as mL/g DMD, mL/g NDFD and mL/g ADFD. Methane production was decreased after 24 h and 48 h only when GA was added at 10 mg/g DM without ethanol. Fermentation liquid pH and concentration of ammonia-nitrogen (ammonia-N) were also reduced (P &amp;lt; 0.05) with an increasing concentration of GA. Treatments with ethanol notably enhanced 48-h DMD, NDFD, ADFD, gas production (mL/g DM, mL/g OM or mL/g DMD), CH4 production (mL/g DM, mL/g DMD or mL/g NDFD), total volatile fatty acid concentration, the acetate:propionate ratio, acetate, valerate, isovalerate and caproate molar proportions (P &amp;lt; 0.01) and decreased propionate, butyrate and isobutyrate molar proportions (P &amp;lt; 0.01). Significant dose of GA × ethanol interaction was observed only for acetate molar proportion (P = 0.03). In conclusion, our study suggests that the beneficial effects of GA on feed digestion and CH4 production may be short term, while improvements in N metabolism may be sustained over the long term. It may be useful to conduct long-term in vivo studies using a range of diets and doses to verify whether GA can be used as a feed additive to mitigate enteric CH4 production and improve N metabolism of ruminants.

Ruminal degradability of brown-midrib sorghum-sudangrass hybrids for cutting and grazing

Greater ruminal degradability has been reported in mutant plants with brown midrib (bmr). The aim of this study was to evaluate the in situ degradability of dry matter (DM), neutral detergent fibre (NDF) and crude protein (CP) in the experimental sorghum-sudangrass bmr hybrids BR007 x Tx2784bmr and Tx635x Tx2785bmr, conventional experimental hybrids CMSxS206 x Tx2784 and Tx636 x Tx2785, and the control hybrid BRS801, harvested 51 days after planting. Three sheep with ruminal cannulae were used. The experimental design was of randomised complete blocks in subdivided lots. The mean values for DM and NDF disappearance were higher in the bmr hybrids after 6 h incubation. These plants had a higher rate of degradation (mean value of 6.93%/h) for fraction b of the DM compared to conventional plants (mean value of 5.73%/h), and greater effective DM degradability. The mean values for effective NDF degradability at passage rates of 2, 5 and 8%/h were 72.7% and 62.0%, 56.1% and 45.6%, and 47.1% and 37.3% for the bmr and conventional hybrids respectively. The experimental mutant hybrids showed higher values for effective CP degradability in relation to the remainder, however, the differences were more subtle in relation to those seen for DM and NDF. The results of the present work show the potential of using sorghum-sudangrass bmr hybrids in systems of ruminant production with high nutritional requirements.

Effects of feeding corn plant residues during the growing phase on steer growth performance and feedlot economics

ABSTRACT Feeding harvested corn crop residues (CCR) to cattle has become increasingly common; however, the poor quality of mature CCR presents nutritional challenges. Therefore, the objectives of these studies were to evaluate the effects of feeding CCR harvested at 2 maturities and the effects of 2 silage additives, Silage SAVOR Plus (propionic acid-based additive) or Silo-King (lactobacillus-based additive), on in situ fiber disappearance, cattle growth performance and carcass characteristics, and economic traits of growing cattle. A total of 128 Angus × Simmental steers (initial BW = 327 ± 40 kg) were allotted to 20 pens and fed 4 treatments in diets that contained 25% forage: (1) corn stover, wetted to 40% DM and ensiled; (2) corn stalklage, harvested at 40% DM and ensiled (STK); (3) STK plus Silo-King; or (4) STK plus Silage SAVOR Plus. Corn stover was harvested 186 d after planting after harvesting dry corn. Corn stalklage was harvested 158 d after planting after harvesting high moisture corn. Growing diets contained CCR at 25% inclusion (DM basis) and were fed from d 0 to 85. From d 86 to 186, steers were fed a common finishing diet. Corn crop residue samples were incubated in 2 ruminally fistulated steers to determine in situ DM disappearance and NDF disappearance. There were no effects of treatment on in situ DM disappearance (P = 0.40) or in situ NDF disappearance (P = 0.34). There were no treatment effects (P ≥ 0.19) on steer growth performance from d 0 to 85 and from d 86 to 186; thus, there were no effects (P ≥ 0.14) of treatment on overall steer performance, carcass characteristics, and economic traits for the entire 186 d. Feeding mature CCR resulted in similar ruminal fiber degradation, steer growth, carcass performance, and economic traits when compared with immature CCR in diets fed to growing steers, and there was no benefit of additive inclusion.

Meta-analysis: effects of exogenous fibrolytic enzymes in ruminant diets

ABSTRACTThere are unknown interactions between supplements of exogenous fibrolytic enzymes (EFE) and the cell walls of feedstuff in ruminal conditions. The quantitative effects of using EFE in ruminant diets were evaluated using meta-analysis. Records (586) were extracted from 74 journal articles from a list of published papers (2000–2012). Statistical analyses were performed considering fixed [type of forage-based diet, forage-to-concentrate ratio (F:C ratio) and primarily enzyme activities in the EFE], and random effects [Experiment(Article)]. In dairy cows fed high-forage (F:C ≥50%), the supplementation of primarily mixtures of cellulases and xylanases (Cel:Xyl: 1:4–1:1) increased milk production and milk composition of legume-based diets, and primarily xylanases (Xyl) EFE improved those variables of grass-based diets. In F:C <50% grass-based diets, Cel:Xyl improved the average daily gain (ADG) and feed conversion [FC:DM intake (DMI)/ADG] of beef cattle. DMI of dairy cows was not affected by EFE supplementation, but EFE improved the DMI of beef cattle. EFE effects were inconsistent in sheep productive performance variables. Cellulases (Cel) and Xyl enhanced in vivo dry matter (DM) digestibility (DMD) in low-forage (F:C <50%) grass-based diets. In F:C ≥50% legume-based diets, EFE enhanced the in situ DM disappearance (ISDMD), and mainly Cel:Xyl improved the in situ neutral detergent fibre (NDF) disappearance (ISNDFD), but there were no effects in those variables in F:C ≥50% grass-based diets. Regardless of the type of ruminal liquid (RL) or forage, in F:C ≥50% diets, in vitro DM degradability (IVDMD) was improved mainly by Cel, but fibre degradability only was improved by Cel:Xyl when sheep RL was used for in vitro evaluations. Overall, EFE could improve the productive performance of dairy cows and beef cattle, but the response depends upon the proper mixture of Cel and Xyl according to the diet composition.Abbreviations: ADF: acid detergent fiber; ADG: average daily gain; A:P: acetate:propionate ratio; BW: initial body weight; Cel:Xyl: cellulases:xylanases; DM: dry matter; DMD: in vivo dry matter digestibility; DMI: dry matter intake; EA: enzyme activities; EFE: exogenous fibrolytic enzymes; F: type of forage; FC: feed conversion; F:C: forage-to-concentrate ratio; ISDMD: in situ dry matter disappearance; ISNDFD: in situ neutral detergent fiber disappearance; IVADFD: in vitro acid detergent degradability; IVDMD: in vitro dry matter degradability; IVNDFD: in vitro neutral detergent fiber degradability; NDF: neutral detergent fiber; VFA: in vitro volatile fat acids

Comparative digestibility of nutrients and amino acids in high-fiber diets fed to crossbred barrows of Duroc boars crossed with Berkshire×Jiaxing and Landrace×Yorkshire.

ObjectiveThis experiment was conducted to determine the differences in the apparent ileal (AID) and total tract digestibility (ATTD) of nutrients and indispensable amino acids (IAA) in high-fiber diets with wheat middlings, rice bran or alfalfa meal fed to Duroc×(Landrace× Yorkshire) (DLY) and Duroc× (Berkshire×Jiaxing) (DBJ) growing barrows.MethodsEighteen DLY and 18 DBJ growing barrows were randomly allotted to a 2×3 factorial arrangement involving 2 crossbreeds and 3 high-fiber diets. The experiment lasted 15 d with 10 d for diets adaptation, 3 d for feces collection and 2 d for digesta collection. Three diets were based on corn and soybean meal with 25% wheat middlings, rice bran and alfalfa meal respectively.ResultsDBJ had a greater (p<0.05) AID of isoleucine, leucine, lysine, phenylalanine and valine and a lower (p<0.05) AID of methionine than DLY. The hindgut disappearance of acid detergent fiber for DBJ was greater (p<0.05) than DLY. The ATTD of gross energy, dry matter, organic matter, neutral detergent fiber and acid detergent fiber in wheat middlings diet were greater (p<0.05) than in rice bran and alfalfa meal diets. The hindgut disappearance of neutral detergent fiber and acid detergent fiber in wheat middlings diet or rice bran diet were the highest or lowest (p<0.05), and those of alfalfa meal diet were the middle. Barrows fed rice bran diet had a greater (p<0.05) hindgut disappearance of gross energy, dry matter and organic matter and lower hindgut disappearance of neutral detergent fiber and acid detergent fiber than barrows fed alfalfa meal dietConclusionDBJ growing barrows showed a significant higher digestibility of fiber in the hindgut and most IAA in the small intestine compared with DLY barrows. The digestibilities of chemical constituents and IAA were affected by the diets formulated with different fiber sources.

Digestibility and performance of steers fed varying inclusions of corn silage and modified distillers grains with solubles to partially replace corn in finishing diets.

Two finishing and 1 digestibility experiment evaluated the partial substitution of corn with corn silage and corn modified distillers grains with solubles (MDGS). Steers were used in Exp. 1 (n = 295; 467 ± 52 kg) and Exp. 2 (n = 225; BW = 348 ± 27 kg) in a 2 × 2 + 1 factorial arrangement of treatments with factors including corn silage (15 or 45%) and MDGS (20 or 40%) plus a control diet consisting of 5% cornstalks and 40% MDGS. In Exp. 1, there were tendencies for a corn silage × MDGS interaction for ADG, final BW, and G:F (P ≤ 0.08). In the overall F-test for G:F, there were no differences between the control treatment and 15:20, 15:40, or 45:40 (P ≥ 0.15), however, steers fed the control treatment had increased G:F compared to steers fed 45:20 treatment diets (P = 0.03). In Exp. 2, there were no corn silage × MDGS interactions (P ≥ 0.12). As corn silage increased in the diet, ADG, final BW, and G:F decreased (P ≤ 0.01). As MDGS increased from 20 to 40%, ADG and G:F tended to improve (P ≤ 0.07). In the overall F-test, the control was not different for G:F from 15:20, 45:20, or 45:40 (P ≥ 0.15), but had a 4.8% poorer G:F compared to 15:40 (P < 0.01). In Exp. 3, ruminally fistulated steers (n = 6) were used in a 5 × 6 Latin rectangle design and fed 15 or 45% corn silage with 20 or 40% MDGS as a 2 × 2 factorial. An additional diet consisting of 95% corn silage and 5% supplement was fed. There were no corn silage × MDGS interactions for nutrient intake, total tract digestibility, ruminal pH measurements, acetate: propionate ratio (A:P), or in-situ disappearance data (P ≥ 0.31) for the 2 × 2 factorial. As corn silage increased in the diet, DMI, NDF intake, ruminal pH, A:P, in-situ NDF disappearance of corn bran, and DM disappearance of corn increased (P ≤ 0.09) with decreases in DM and OM digestibility (P ≤ 0.03). As MDGS increased in the diet, there was an increase in NDF intake, total volatile fatty acid concentration, and NDF disappearance of corn bran (P ≤ 0.03) with no differences for any other tested variables (P ≥ 0.13). In general, increasing corn silage in place of corn in finishing diets containing MDGS results in a modest reduction in ADG and G:F with increases in ruminal pH.

489 Effects of the inclusion of linseed and increasing concentrations of glycerol as replacement of corn grain on rumen fermentation, methane production and nutrient disappearance in a rusitec system

The aim of the study was to assess the effects of using linseed and increasing concentrations of glycerol in a forage diet supplemented with corn grain on nutrient disappearance, methane (CH4) production and fermentation parameters in a Rusitec fermentation system. The experimental diets were: control, (70% ryegrass/clover mixed hay, 30% corn grain); positive control (70% hay, 15% corn grain, 15% linseed); 5% glycerol (70% hay, 10% corn grain, 15% linseed, 5% glycerol); 10% glycerol (70% hay, 5% corn grain, 15% linseed, 10% glycerol). The experiment was a complete randomized design with the four dietary treatments with 2 replicates in an 8 fermenter Rusitec apparatus. Incubations were run twice during 15d. The first 10d were used for fermenter adaptation, followed by 5d of sampling (days 11 to 15). The individual fermenter was the experimental unit. The model included the fixed effects of diet, day and diet/day interactions with the day of sampling from each fermenter treated as a repeated measure. Total VFA concentrations in effluent were increased (P = 0.005) in the glycerol added diets as compared to positive control. Acetate concentrations were reduced with increasing glycerol concentration in diets whereas propionate increased with linseed inclusion. Increasing concentrations of glycerol resulted in further increased propionate concentrations (P < 0.001), thus leading to important reductions in the acetate/propionate ratio. However, CH4 production (mgCH4/g DM digested) was reduced by linseed inclusion in the diet (P = 0.004) but not by increasing concentrations of glycerol in the diet. Ammonia nitrogen was increased in all linseed supplemented diets (P < 0.001). Total DM and non-fibrous carbohydrates in vitro disappearance were not affected by dietary treatments (P = 0.411). However, CP and EE disappearance were increased in linseed supplemented diets (P < 0.001) but not further affected by glycerol inclusion. Disappearance of NDF was increased only in the positive control diet as compared to control diet (P = 0.0185). In conclusion, the use of linseed as replacement of corn grain reduces CH4 production in a Rusitec system but increases ammonia nitrogen. Increased propionate concentrations in glycerol supplemented fermenters does not result in reduced CH4 production despite increases in propionate concentrations. Linseed inclusion increases in vitro disappearance of CP and EE without affecting total DM disappearance.

ソルゴーの利用について : 第3報 細胞膜構成物質について

ソルゴーの利用について : 第3報 細胞膜構成物質について

Evaluation of three medicinal plants for methane production potential, fiber digestion and rumen fermentation in vitro

Effects of three selected medicinal plants on fermentation patterns and to evaluate their potential as antimethanogenic additives in ruminant feeds were studied. Effects of Nigella sativa, Rosmarinus officinalis and Zingiber officinale, which were added to the fermentation substrate as a dry powder, on ruminal fermentation, fibre digestion and methane production, were studied in vitro in batch cultures of mixed rumen microorganisms. Serum bottles containing 500 mg of substrate (a mixture of 500 mg of alfalfa hay, 400 mg of grass hay and 100 mg of barley grain per gram), 50 mg of the plant tested and 50 ml of buffered rumen fluid (10 ml sheep rumen fluid + 40 ml culture medium) were incubated at 39 ºC for 24 h. After incubation, gas and methane production, pH and volatile fatty acid (VFA) concentration in the incubation medium and dry matter and neutral detergent fibre disappearance were recorded. The amounts of methane produced after 24 hours of fermentation varied between 0.28 and 1.12mmol/gDM. A significant methane reduction was observed with monensin (75% less methane than control) and Nigella sativa (20% less methane than control) and no effect was observed with the other treatments. Further studies are warranted to confirm the antimethanogenic activity of Nigella sativa, establish a dose-response relationship, examine the stability in time of the effects, and test if the effects can be reproduced in vivo with animals.

Replacement of alfalfa hay (Medicago sativa L.) with subabul (Leucaena leucocephala) leaf meal in diets of Najdi goats: effect on digestion activity of rumen microorganisms.

This study investigated the effect of replacing alfalfa hay by subabul leaf meal (SLM) on digestion, fermentation parameters and rumen bacteria and fungi activity of Najdi goats. Six Najdi goats (150±15days of age and initial body weight of 35±1.1kg) were randomly assigned to one of two dietary treatments in a balanced completely randomized design (three goats per treatment) for 56days. Experimental treatments included alfalfa hay as control group and diet containing SLM (SLM replacing alfalfa hay at 50% level). Bacterial and fungi activity and rumen fermentation parameters of animals fed experimental diets were determined. Dry matter disappearance (DMD) was unaffected by replacing SLM with alfalfa hay for both rumen bacteria and fungi in different incubation times, except for 48h of incubation in specific culture medium of mixed rumen bacteria, which decreased for SLM group (P>0.05). NDF disappearance (NDFD) and ADF disappearance (ADFD) after 24 and 48h of incubation in specific culture medium of mixed rumen bacteria was not affected by experimental diets (P>0.05). However, 72h after incubation, NDFD in SLM treatment decreased (P>0.05). Gas production parameters of rumen bacteria were similar for both experimental diets, but partitioning factor (PF), efficiency microbial biomass production (EMBP), microbial protein production (MP), and organic matter truly digested (OMTD) decreased (p<0.05) in specific culture medium of mixed rumen fungi for SLM diet. There was significant decrease in total protozoa population for diet containing SLM (p<0.05). Results indicated that replacement of alfalfa hay by SLM had no major effect on rumen microorganisms' activity of Najdi goats, so it may be used as an alternative for alfalfa (at 50% level) in susceptible areas.

In vitro response to EPA, DPA, and DHA: Comparison of effects on ruminal fermentation and biohydrogenation of 18-carbon fatty acids in cows and ewes.

The modulation of milk fat nutritional quality through fish oil supplementation seems to be largely explained by the action of n-3 very long chain polyunsaturated fatty acids (PUFA) on ruminal biohydrogenation (BH) of C18 fatty acids (FA). However, relationships among this action, disappearance of those PUFA in the rumen, and potential detrimental consequences on ruminal fermentation remain uncertain. This study compared the effect of 20:5n-3 (eicosapentaenoic acid; EPA), 22:5n-3 (docosapentaenoic acid; DPA), and 22:6n-3 (docosahexaenoic acid; DHA) on rumen fermentation and BH of C18 FA and was conducted simultaneously in cows and sheep to provide novel insights into interspecies differences. The trial was performed in vitro using batch cultures of rumen microorganisms with inocula collected from cannulated cows and ewes. The PUFA were added at a dose of 2% incubated dry matter, and treatment effects on ruminal C18 FA concentrations, PUFA disappearances, and fermentation parameters (gas production, ammonia and volatile FA concentrations, and dry matter and neutral detergent fiber disappearances) were examined after 24 h of incubation. A principal component analysis suggested that responses to PUFA treatments explained most of the variability; those of ruminant species were of lower relevance. Overall, EPA and DHA were equally effective for inhibiting the saturation of trans-11 18:1 to 18:0 and had a similar influence on ruminal fermentation in cows and sheep (e.g., reductions in gas production and acetate:propionate ratio). Nevertheless, DHA further promoted alternative BH pathways that lead to trans-10 18:1 accumulation, and EPA seemed to have specific effects on 18:3n-3 metabolism. Only minor variations attributable to DPA were observed in the studied parameters, suggesting a low contribution of this FA to the action of marine lipids. Although most changes due to the added PUFA were comparable in bovine and ovine, there were also relevant specificities, such as a stronger inhibition of 18:0 formation in cows and a greater increase in 18:3n-3 metabolites in sheep. No direct relationship between in vitro disappearance of the incubated PUFA and effect on BH (in particular, inhibition of the last step) was found in either cows or ewes, calling into question a putative link between extent of disappearance and toxicity for microbiota. Conversely, an association between the influence of these PUFA on ruminal lipid metabolism and fermentation may exist in both species. In vivo verification of these findings would be advisable.

Using brown midrib 6 dwarf forage sorghum silage and fall-grown oat silage in lactating dairy cow rations

Double cropping and increasing crop diversity could improve dairy farm economic and environmental sustainability. In this experiment, corn silage was partially replaced with 2 alternative forages, brown midrib-6 brachytic dwarf forage sorghum (Sorghum bicolor) or fall-grown oat (Avena sativa) silage, in the diet of lactating dairy cows. We investigated the effect on dry matter (DM) intake, milk yield (MY), milk components and fatty acid profile, apparent total-tract nutrient digestibility, N utilization, enteric methane emissions, and income over feed cost. We analyzed the in situ DM and neutral detergent fiber disappearance of the alternative forages versus corn silage and alfalfa haylage. Sorghum was grown in the summer and harvested in the milk stage. Oats were grown in the fall and harvested in the boot stage. Compared with corn silage, neutral detergent fiber and acid detergent fiber concentrations were higher in the alternative forages. Lignin content was highest for sorghum silage and similar for corn silage and oat silage. The alternative forages had less than 1% starch compared with the approximately 35% starch in the corn silage. Ruminal in situ DM effective degradability was similar, although statistically different, for corn silage and oat silage, but lower for sorghum silage. Diets with the alternative forages were fed in a replicated 3 × 3 Latin square design experiment with three 28-d periods and 12 Holstein cows. The control diet contained 44% (DM basis) corn silage. In the other 2 diets, sorghum or oat silages were included at 10% of dietary DM, replacing corn silage. Sorghum silage inclusion decreased DM intake, MY, and milk protein content but increased milk fat and maintained energy-corrected MY similar to the control. Oat silage had no effect on DM intake, MY, or milk components compared to the control. The oat silage diet increased apparent total-tract digestibility of dietary nutrients, except starch, whereas the sorghum diet slightly decreased DM, organic matter, crude protein, and starch digestibility. Cows consuming the oat silage diet had higher milk urea N and urinary urea N concentrations. Milk N efficiency was decreased by the sorghum diet. Diet did not affect enteric methane or carbon dioxide emissions. This study shows that oat silage can partially replace corn silage at 10% of the diet DM with no effect on MY. Brown midrib sorghum silage harvested at the milk stage with <1% starch may decrease DM intake and MY in dairy cows.