Ruminal Dry Matter Disappearance Research Articles

Effects of leaf and stem maturation on nutritional value in Megathyrsus maximus.

Megathyrsus maximus is a forage grass native to Africa but widely cultivated in tropical and subtropical regions of the world where it is part of the grazing food chain. This study aimed to evaluate five M. maximus genotypes for the effect of maturity on their morpho-agronomic traits, nutritional composition and digestibility, and to correlate their leaf blade and stem anatomy with their nutritional value. The proportion of sclerenchyma tissues increased as maturity was reached, while lignin accumulation was differentiated between genotypes. Gatton Panic, Green Panic and Mutale genotypes maintained their acid detergent lignin (ADL) values for leaf blades in the three cuts evaluated. In sacco ruminal dry matter disappearance was lower in Green Panic genotype at the vegetative stage for stems, but not for leaf blades. Significant positive correlations were found between dry matter disappearance and mesophyll tissues, and the latter were negatively correlated with neutral detergent fiber (NDF) and ADL. Our results strongly indicate that cutting age and genotype affected the nutritional value of M. maximus leaf blades and stems, with a more pronounced loss of quality in stems than in leaf blades. We recommend increasing the frequency of grazing at early stage or anticipating the stage of stem elongation in Green Panic to produce forage with better nutritional value. © 2023 Society of Chemical Industry.

Evaluation of degradability of Moringa, Pineapple waste and Plantain herbs by in situ and in vitro gas production technique

Nutritional evaluation of feed ingredients is important for potential use in feed rations. It is very important to determine not only the nutrient content and quality of feeds but also their digestibility prior to adding in the ration. This study was undertaken to assess the potential nutritive value of selected shade-dried herbs of moringa, pineapple waste, and plantain through in situ degradation and in vitro gas production techniques. The study compared 4 treatments, namely moringa (MH), pineapple waste (PwH), plantain (PH) herbs, and a combination of three of them with a ratio of 1:1:1 (MxH). The rumen dry matter (DM) and crude protein (CP) degradability kinetics were analyzed by using the nylon bags (in situ) procedure and the organic matter digestibility and fermentation characteristics were analyzed by in vitro gas production technique. The results of the in situ study revealed that the ruminal dry matter disappearance differed significantly (P<0.001) among herbs at all incubation periods whereas the PH had the greatest disappearance and PwH had the lowest among all herbs. Significantly (P<0.05) the highest potential and effective degradability of dry matter were found in PH and the lowest in PwH among herbs. The ruminal CP disappearance differed significantly (p<0.05) among herbs at all incubation periods. The MH had the greatest CP disappearance whereas PwH had the lowest. Significantly (P<0.05) the highest potential and effective degradability of CP were found in MH and MxH, respectively, and the lowest in PwH among herbs. The results of the in vitro study revealed that cumulative gas production was increased with increasing the periods of incubation for all herbs. Significantly (P<0.05) the highest gas production was found in PH and MH among all herbs at 48h of incubation. The organic matter digestibility and metabolizable energy were found significantly (P<0.05) higher in MH & PH and lower in PwH. Short-chain fatty acids were also significantly (P<0.05) higher in MH & PH and lower in PwH among herbs. It may be concluded that both plantain and moringa herbs showed better potential and effective degradability and also higher organic matter digestibility and metabolizable energy comparable to pineapple waste herbs. Bangladesh Journal of Animal Science 52 (3): 88-98.

PSXVI-6 Ruminal dry Matter Disappearance, Methane Production and Fermentation Parameters as Affected by fat and Protein Concentration in by-Product Supplemented Grass hay-Based Diets

Abstract This batch culture study evaluated the effects of crude protein (CP) and fat concentration on ruminal dry matter disappearance (DMD), methane (CH4) production, and ruminal fermentation in grass hay-based diets supplemented with by-product feeds. Eight treatments provided low or high CP (8 or 12% DM, respectively), with a range of fat concentrations (1.8 to 6.0% DM) and included the following: Control (grass hay only); corn distillers grains with solubles at 8.0% (CDDGS8) and 12% CP (CDDGS12); flax at 8% (FS8) and 12% CP (FS12); canola meal at 8% (Can8); sunflower screenings from Winkler (SFW8) or Deloraine (SFD8) at 8%. Data were analyzed as a randomized complete block design, with fixed effect of treatment and random effects of block and treatment × block. Comparisons were performed between a) Control and mean of by-product treatments b) low and high CP treatments c) CDDGS treatments, d) FS treatments and e) SF treatments. Comparisons between low and high fat treatments at both CP concentrations, as well as CDDGS and FS treatments differing in fat concentrations were also conducted. Overall, DMD did not differ between the Control and by-product treatments; however, comparisons indicated decreased (P < 0.001) DMD in treatments with 8% compared with 12% CP. The DMD was also greater (P≤0.009) with low fat compared with high fat, regardless of CP. Methane production did not differ between any of the low and high CP treatments but was greater (P≤0.003) in the low fat compared with high fat treatments, regardless of CP, as well as in FS vs CDDGS and SFD vs SFW. No effects of treatment on fermentation parameters were observed. In conclusion, greater CP increased DMD in vitro but did not affect CH4 or fermentation. Additionally, greater dietary fat can mitigate enteric CH4 production, but can negatively impact DMD in grass hay-based diets.

Ruminal dry matter disappearance, total gas and methane production, and fermentation parameters as affected by fat and protein concentration in by-product supplemented grass hay-based diets

Context Dietary manipulation is an important means to mitigate methane emissions; however, relatively few options exist for forage-based diets. Aims This batch culture study evaluated the effects of crude protein (CP) and fat concentration on ruminal DM disappearance (DMD), total gas (GP) and methane production, and ruminal fermentation in grass hay-based diets supplemented with a range of by-product feeds. Methods Eight treatments provided low or high CP (8 or 12% diet DM, respectively), with range of fat concentrations (1.8–6.0% diet DM), and included: control (grass hay only); corn distillers grains with solubles at 8% (CDDGS8) and 12% CP (CDDGS12); flax at 8% (FS8) and 12% CP (FSCDDGS12); canola meal at 8% (Can8); and sunflower screenings from Winkler (SFW8) or Deloraine (SFD8) at 8%. Data were analysed as a randomised complete block design, with fixed effect of treatment and random effects of block and treatment × block. Comparisons were performed between: (1) control and mean of by-product treatments, (2) low and high CP treatments, (3) CDDGS treatments, (4) FS treatments, and (5) SF treatments. Low- and high-fat treatments at both CP concentrations, and the means of CDDGS and FS treatments differing in fat concentrations were also compared. Key results The DMD did not differ between control and by-product treatments; however, DMD was lower (P < 0.001) in treatments with 8% compared with 12% CP, and was higher (P ≤ 0.009) with low fat compared with high fat, regardless of CP. Total GP was not affected by CP; however, at low CP, treatments with higher fat had lower GP (P ≤ 0.015). Methane production did not differ between any of the low and high CP treatments, but was higher (P ≤ 0.003) in the low-fat compared with high-fat treatments, regardless of CP, as well as in FS versus CDDGS and SFD versus SFW. Conclusions Higher CP increased DMD in vitro, but did not affect GP, methane or fermentation. Implications Higher dietary fat can mitigate enteric methane production, but can negatively impact DMD in grass hay-based diets, which is an important consideration in terms of animal performance.

In situ ruminal degradation of sallow tree leaves using different mathematical models

Objective. The objective of this study was to determine the in situ digestion parameters of sallow leaves (Salix Alba) as an alternative food, not commonly used in animal diets using mathematical models. Materials and methods. Four mathematical models were used to describe the ruminal disappearance of dry matter (DM) and crude protein (CP) of sallow leaves: non lagged exponential (Model I); lagged exponential (Model II); Gompertz (Model III), and generalized Mitscherlich (Model IV). Results. Results of DM and CP degradability characteristics showed that all the models fitted well (r2>0.98) to the disappearance data. There were minor differences between the models in terms of statistical evaluations. However, the models differed in the estimated parameters depending on the model’s nature and structure and the parameters included. Conclusions. Given that some models estimated negative values for the studied parameters, they were not biologically acceptable. For this reason, the only model I can be used for estimating the degradability of DM and CP of sallow leaves. In terms of effective degradability (ED) of DM, model III was not used in the calculations because of calculating negative values for part A. Sallow leaves constitute the largest possible proportion of the ruminal degradability fractions, and effective degradability can be used as a forage source in ruminant feeds.

Comparative effects of extracted polyphenols from black and green tea wastes on in-vitro fermentability of feed ingredients

The effect of using black and green tea waste extracts on the diet nutritional value was investigated with three methods of in vitro degradability, gas production, and McNiven’s enzymatic digestion in the present experiment. Total phenolic compounds and total tannin for green tea extract were 20.3% and 14.8% of dry matter (DM), respectively, and for black tea were 18.7% and 12.7% of dry matter, respectively. The addition of green and black tea waste extracts reduced both gas production during incubation hours and dry matter degradability (DMD) in the diet (p < 0.05). A significantly reduced ruminal dry matter disappearance (p < 0.05) and a significantly increased post-ruminal dry matter disappearance (p < 0.05) were observed by adding black and green tea waste extracts. According to the results, the dry matter disappearance throughout the gastrointestinal tract was not significantly different between treatments. It can generally be concluded that the addition of phenolic compounds can be used depending on the nutritional strategy, such as reducing ruminal degradability and increasing rumen nutrient escape.

Mathematical models describing disappearance of Lucerne hay in the rumen using the nylon bag technique

It is essential to study the dynamics of rumen degradation of feeds before their potential use in formulating diets for ruminants. Various mathematical models have been developed to describe this degradation. The non-lagged exponential model (Model I), the lagged exponential model (Model II), the Gompertz model (Model III), and the generalized Mitscherlich model (Model IV) were examined using two alternative software (SAS and MATLAB) to determine their efficacy in accounting for variation in ruminal disappearance of dry matter (DM) and crude protein (CP) of lucerne hay from three cuttings. All models described DM degradability well (R2 >0.98). Only Models I and II converged when fitted to CP degradability data (R2 >0.98). It was concluded that any of these models could be used to describe the degradation of DM, whereas only Models I and II could be used to describe the degradation of CP from three cuttings of Lucerne hay. All the models that were fitted to the DM degradation data performed reasonably well, with only minor differences in goodness of fit. However, these models differed in values of the parameter estimates. Additionally, SAS failed to converge in the analyses of CP with Models III and IV, and MATLAB converged to nonsensical values with Model III. Model I might be recommended because it fitted the data well and required estimates of the fewest parameters
 Keywords: alfalfa hay, in situ digestion, model selection, nonlinear regression

Validation of in situ disappearance curves utilizing mathematical models for incubating fish meal and cottonseed mea

our mathematical models were used to describe the ruminal disappearance of dry matter (DM) and crude protein (CP) of fish meal and cottonseed meal. Results of DM degradability particularity showed that all the models fitted well (R2 > 0.95), however, considering that values below 0 or above 100 are not biologically justified in ruminal degradability, they are not acceptable. The models I and II were accepted to ruminal DM degradability of fish meal and cottonseed meal data. Only models I and II were successfully fitted to CP degradability of fish meal (R2 > 0.96), and the I, II and III models were acceptable to ruminal CP degradability of cottonseed meal (R2 > 0.98). In terms of effective degradability (ED) of DM and CP, model II generated higher values than other models. To appreciate fully the role of mathematical modelling in the biological sciences, it is necessary to consider the nature of feeds that evaluated and to review the types of models that may be constructed.

Impact of filament denier on functional performance of microfiber in situ bags

In situ bags made from microfiber fabrics have a greater surface area and filtration efficiency that retains the fine particles and reduce the variation in the results. Also, it is more durable than that made from traditional fabrics. This work aimed to study the effect of filament denier on the performance of in situ bags. Two polyester microfilaments with 0.4 and 0.7 deniers were used in manufacturing of four fabrics. Physical and mechanical properties of manufactured fabrics were measured before and after incubation to show the efficiency of the manufactured samples. In vitro trail was conducted to estimate ruminal degradability after 24 and 48 hours for three feedstuffs using three cannulated rams as replicates. The mechanical properties of manufactured in situ bags were significantly affected with both denier per filament and weft densities. According to the statistical analysis of radar chart, sample 2 remarked the highest value which achieved the acceptable ruminal dry matter disappearance compared with Ankom bags in different incubation times.

Effects of processing, moisture, and storage length on the fermentation profile, particle size, and ruminal disappearance of reconstituted corn grain.

Our objective was to examine the effects of processing, moisture, and anaerobic storage length of reconstituted corn grain (RCG) on the fermentation profile, geometric mean particle size (GMPS), and ruminal dry matter disappearance (DMD). Dry corn kernels were ground (hammer mill, 5-mm screen) or rolled, then rehydrated to 30%, 35%, or 40% moisture, and stored for 0, 14, 30, 60, 90, 120, or 180 d in laboratory silos. Rolled corn had an increased GMPS compared with ground corn (2.24 and 1.13 mm, respectively, at ensiling). However, there was a trend for an interaction between processing and moisture concentration to affect particle size, with GMPS increasing with increased moisture concentration, especially in ground corn. Longer storage periods also slightly increased GMPS. Processing, moisture, and storage length interacted to affect the fermentation pattern (two- or three-way interactions). Overall, pH decreased, whereas lactic acid, acetic acid, ethanol, and NH3-N increased with storage length. RCG with 30% moisture had less lactic acid than corn with 35% and 40% moisture, indicating that fermentation might have been curtailed and also due to the clostridial fermentation that converts lactic acid to butyric acid. Ensiling reconstituted ground corn with 30% of moisture led to greater concentrations of ethanol and butyric acid, resulting in greater DM loss than grain rehydrated to 35% or 40% of moisture. Ammonia-N and in situ ruminal DMD were highest for reconstituted ground corn with 35% or 40% of moisture, mainly after 60 d of storage. Therefore, longer storage periods and greater moisture contents did not offset the negative effect of greater particle size on the in situ ruminal DMD of rolled RCG. Nonetheless, RCG should be ensiled with more than 30% moisture and stored for at least 2 mo to improve the ruminal DMD and reduce the formation of ethanol and butyric acid.

Losses, chemical composition and aerobic stability of rye silage cv. Temprano subjected to different pre-flowering cuttings with or without fungicide

The present study evaluated the fermentation, chemical characteristics and ruminal disappearance of dry matter of silages of rye cv. Temprano harvested at the stage of floury grain, managed with or without cutting at the vegetative stage and with or without application of Fluxapyroxad + Pyraclostrobin-based fungicide at the pre-flowering phenological stage. This was a 2x2 factorial randomized block experimental design, with 2 cutting regimes (0 and 1 cut) and 2 application management (with and without fungicide), with six replications, where each repetition is represented by a plot of 9.45m², with the treatments SC-SF: without cut at the vegetative stage and without fungicide application; SC-CF: without cut at the vegetative stage with fungicide application; UC-SF: a cut at the vegetative stage with pre-flowering fungicide application; UC-CF: a cut at the vegetative stage and without fungicide application. UC-CF silages were better in the general context, due to the better fiber composition with an average 6.75% reduction in neutral detergent fiber and acid detergent fiber and a 17.10% reduction in lignin content, but, due to its higher DM content, it presented a less efficient fermentation process in terms of organic acid concentration and aerobic stability. However, it did not change the DM losses or ruminal degradability, and there is also the use of DM harvested at the vegetative stage that certainly has a superior quality. The use of fungicide provided only better dry matter index and better fiber composition and improved the fermentation process resulting in lower DM losses without altering the aerobic stability of silages.

Chemical parameters and ruminal disappearance of Secale cereale rye forage in different harvest systems with or without fungicide

The objective of the study was to evaluate the chemical parameters and the ruminal disappearance of dry matter of forage from the rye Secale cereale, cv. Temprano managed in different harvest regimes at the vegetative stage, with or without application of a fungicide based on Fluxapyroxade + Piraclostrobin at the pre-flowering stage. This was a randomized block experimental design and the treatments consisted of evaluating the forage harvested at floury grain stage, as follow, SCSF: no cut at the vegetative stage, no application of fungicide; SCCF: no cut at the vegetative stage with fungicide application; UCSF: one cut at the vegetative stage, no application of fungicide; UCCF: one cut with fungicide application; DCSF: two cuts at the vegetative stage, no fungicide application; DCCF: two cuts with fungicide application. In general, one cut at the vegetative stage and a subsequent cut for ensiling at floury grain stage was the best system used in cv. Temprano, based on the chemical parameters and ruminal disappearance. This system provided a better composition of fiber carbohydrates with lower contents of Acid Detergent Fiber (41.55%) and Lignin (10.79%) after cutting and resulted in a better disappearance rate of dry matter at the rumen level (0.46 %) per hour of exposure, highlighting the cut at the vegetative stage that produced a material with 20.76% Crude Protein and 52.69% Neutral Detergent showing its nutritional quality for use in grazing land or as haylage. The application of fungicide provided significant improvements in the contents of crude protein (8.24% vs 7.23%) and mineral matter (3.02% vs 2.82%) of the plant at the time of ensiling, which generated better dry matter disappearance rates in the rumen.

Ruminal in situ disappearance and whole-tract digestion of starter feeds in calves before, during, and after weaning

Ten bull calves (n = 5/diet) were cannulated at 3 wk of age and used in a 2 × 2 factorial design with repeated measures over time to compare rumen and whole-tract degradability of 2 calf starter diets and to describe an in situ technique for estimating ruminal degradability of diets in calves at different ages. Calves received milk replacer and 1 of 2 starter diets through wk 7. Mean birth weight was 38.7 ± 1.3 kg. Weaning occurred in wk 8, and calves received only starter (up to 4,500 g/d) through wk 15. Starter diets were a complete pellet (PEL; 42% starch, 13% neutral detergent fiber, NDF) or texturized feed (TEX; 31% starch, 22% NDF). Portions of each diet were dried and ground through a 2-mm screen, and 1.25 g was inserted into concentrate in situ bags (5 cm × 10 cm, 50-µm porosity). Each calf received duplicate bags of each diet for a total of 8 bags/calf (2 diets × 2 time points). All bags were inserted at the time of starter feeding. Half of the bags were removed at 9 h, and the other half were removed at 24 h. After removal from the rumen, bags were rinsed, dried (55°C), and composited by diet and by calf within week for NDF, nitrogen (N), and starch analyses. This process was repeated over 3 d during wk 5, 7, 9, 11, 13, and 15. Daily starter intake and total fecal excretion were recorded during the same 3-d periods. Diets, refusals, and feces were subsampled, dried, ground, composited by calf by week, and analyzed for NDF, N, and starch content. Apparent digestibility coefficients, total intake, and fecal excretion were calculated and analyzed with a mixed models procedure. Intake and fecal excretion of all measured nutrients increased from wk 5 through wk 15 of age and were greater for calves fed TEX, whereas the proportion of dry matter (DM), N, and starch apparently digested through the total tract decreased from wk 5 to 15 and was greater in calves fed PEL. Ruminal disappearance of DM, N, and starch after 9-h incubations increased linearly with age. Likewise, DM, NDF, and N disappearance after 24-h incubations also increased. Ruminal disappearance of DM and NDF was greater for PEL than for TEX. Ruminal disappearance was estimable for DM, NDF, N, and starch. In addition, changes over time and changes due to rumen environment were clearly demonstrated. Based on these data, there is potential to design specific rations and feed processing methods for calves based on their ability to utilize nutrients.

Short communication: Ground corn steeped in citric acid modulates in vitro gas production kinetics, fermentation patterns and dry matter digestibility

This study investigated the effect of citric acid (CA) concentration and steeping time (ST) treatment of ground corn on ruminally resistant starch (RRS) contents and subsequent effects on starch resistance to rumen degradation using batch culture technique. It was hypothesized that CA concentration and ST are keys affecting the RRS in CA treated ground corn. The experiment was 3 × 3 factorial arrangement using three CA solutions combined with three ST. Ground corn (2 mm) was steeped in an equal quantity (i.e., in a ratio of 1:1, w/v) of tap water alone (Ctr), of 5 (Low) or 10 g/L (High) CA solution for 12, 24 or 48 h. Chemical composition of CA treated corn was measured, and gas production (GP), volatile fatty acids (VFA), NH3-N and dry matter (DM) disappearance (DMD) were determined at 6 and 24 h of incubation. Inocula were obtained from three ruminally cannulated beef heifers fed a diet consisting of 300 g/kg barley silage, 670 g/kg dry rolled barley and 30 g/kg vitamin and mineral supplement (DM basis). No CA × ST interaction was detected. Citric acid treated corn had greater (P < 0.05) RRS than Ctr, with no differences between Low and High CA treatments; the content of RRS was greater (P < 0.05) at 48 h ST than 12 or 24 h. At 24 h of incubation, CA treated corn had lower (P < 0.05) asymptotic cumulative GP, GP rate, DMD, total VFA and NH3-N concentrations than did Ctr. Rate of GP, DMD and NH3-N concentration were highest (P < 0.01) with 12 h, intermediate with 24 h and lowest with 48 h ST at 24 h of incubation. Total VFA concentration was also higher (P < 0.01) with 12 h ST versus 24 and 48 h ST. Production of CH4 and CO2 decreased (P < 0.05) either by CA treatment or with increasing ST. These results indicated that CA treated ground corn increased RRS content, altered fermentation pattern for more acetate production and decreased ruminal DMD in batch culture. Use of CA to treat corn grain can be an effective processing to reduce ruminal corn starch digestion, and thus potentially alleviate risk of rumen acidosis.

Effects of a wax organogel and alginate gel complex on holy basil (Ocimum sanctum) in vitro ruminal dry matter disappearance and gas production.

The objectives of this study were to: (a) select an ideal organogel for the oil phase of a novel gel encapsulation technology, (b) optimize the formulation of an organogel and sodium alginate-based gel complex, and (c) examine the rumen protective ability of the gel by measuring 48-h in vitro ruminal dry matter disappearance and gas production from encapsulated dried and ground holy basil leaves. A rice-bran wax and canola oil organogel was selected for the oil phase of the gel complex as this combination had a 48-h dry matter disappearance of 6%, the lowest of all organogels analyzed. The gel complex was formulated by homogenizing the organogel with a sodium alginate solution to create a low-viscosity oil-in-water emulsion. Average dry matter disappearance of gel-encapsulated holy basil was 19%, compared to 42% for the free, unprotected holy basil. However, gel encapsulation of holy basil stimulated gas production. Specifically, gas production of encapsulated holy basil was four times higher than the treatment with holy basil added on top of the gel prior to incubation rather than encapsulated within the gel. Although the gel itself was highly degradable, it is speculated encapsulation thwarted holy basil's antimicrobial activity. © 2018 Society of Chemical Industry.

トウモロコシ子実の消化性に関する品種間差異の解析 : α-アミラーゼによる消化性とルーメン内消失率及び成分との関係

トウモロコシ子実の消化性に関する品種間差異の解析 : α-アミラーゼによる消化性とルーメン内消失率及び成分との関係

Fermentation characteristics and nutritional quality of elephant grass silage added the buriti fruit peel

The objective of this research was to evaluated the inclusion of buriti fruit peel as additive on the fermentation profile, losses, chemical composition and degradability of elephant grass silage. We used a completely randomized design with five levels of buriti fruit peel (0, 50, 100, 200 and 400 g kg-1). The silos were opened after 28 days of storage. In situ degradability monitoring was conducted using a split-plot design in which four animals represented the blocks and silage supplemented with five levels of buriti fruit peel represented the treatments. The use of the additive in elephant silage increased dry matter (DM) (P &lt; 0.001), ether extract (EE) (P &lt; 0.001), ash (P &lt; 0.001), neutral detergent fiber (NDF) (P &lt; 0.001) and acid detergent fiber (ADF) (P= 0.0000). The pH (P= 0.0000), N-NH3 (P = 0.024) and there was a decrease in gas losses (P &lt; 0.001), effluent losses and dry matter recovery (P = 0.218) not were influenced by the addition of buriti fruit peel. The inclusion of buriti fruit peel linearly reduced the ruminal degradability DM of soluble fraction (a) (P &lt; 0.001) and potentially degradable insoluble fraction (b) (P &lt; 0.001). The DM content increase with the addition of the buriti fruit peel to the elephant grass silage promotes improvements in the fermentation process, reduces losses of nutrients and ruminal disappearance of dry matter and does not significantly change the chemical composition with the inclusion of 166.7 g kg-1 of the buriti fruit peel.

Determination of ruminal dry matter and crude protein degradability and degradation kinetics of several concentrate feed ingredients in cashmere goat

ABSTRACTThe objective of this study was to determine the dry matter (DM) and crude protein (CP) degradation parameters of several commercially available concentrate feed ingredients used in Shaanbei White Cashmere Goat (SWCG). Three 4-year-old female SWCGs fitted with permanent rumen fistula were fed with corn straw and concentrate feed. Tested energy and protein feed ingredients were corn, wheat bran (WB), corn germ meal, soybean meal (SBM), rape seed meal (RSM), and distillers dried grains. The feed samples were placed in a nylon bag and incubated in the rumen for 0, 2, 6, 12, 24, 36, and 48 h to measure the ruminal disappearance of DM and CP. The exponential model was used to calculate the degradation kinetics. There were significant differences between sources in terms of DM and CP disappearance and degradability. In terms of energy feed ingredients, the potential degradability of DM and CP of corn was significantly higher than those of the other energy feed ingredients, whereas the effective degradability (ED) of CP of WB at three outflow rates was significantly higher than those of the others. In protein feed ingredients, SBM had the highest potential degradability of DM and CP. Furthermore, the ED of DM of SBM at three outflow rates was significantly higher than those of the other protein feed ingredients, whereas the ED of CP of RSM at three outflow rates was significantly higher than those of others. Those feed ingredients with low degradability can increase the bypass nutrients, which will be digested in the small intestine. The degradation parameters obtained in this experiment using SWCG would be useful in improving the accuracy of formulation of cashmere goat diet in Northwest of China.

Effects of Medicinal Herb Extracts on In vitro Ruminal Methanogenesis, Microbe Diversity and Fermentation System.

This study was aimed to evaluate the in vitro effects of medicinal herb extracts (MHEs) on ruminal fermentation characteristics and the inhibition of protozoa to reduce methane production in the rumen. A fistulated Hanwoo was used as a donor of rumen fluid. The MHEs (T1, Veratrum patulum; T2, Iris ensata var. spontanea; T3, Arisaema ringens; T4, Carduus crispus; T5, Pueraria thunbergiana) were added to the in vitro fermentation bottles containing the rumen fluid and medium. Total volatile fatty acid (tVFA), total gas production, gas profiles, and the ruminal microbe communities were measured. The tVFA concentration was increased or decreased as compared to the control, and there was a significant (p<0.05) difference after 24 h incubation. pH and ruminal disappearance of dry matter did not show significant difference. As the in vitro ruminal fermentation progressed, total gas production in added MHEs was increased, while the methane production was decreased compared to the control. In particular, Arisaema ringens extract led to decrease methane production by more than 43%. In addition, the result of real-time polymerase chain reaction indicted that the protozoa population in all added MHEs decreased more than that of the control. In conclusion, the results of this study indicated that MHEs could have properties that decrease ruminal methanogenesis by inhibiting protozoa species and might be promising feed additives for ruminants.

Relationship between processing score and kernel-fraction particle size in whole-plant corn silage

Kernel processing increases starch digestibility in whole-plant corn silage (WPCS). Corn silage processing score (CSPS), the percentage of starch passing through a 4.75-mm sieve, is widely used to assess degree of kernel breakage in WPCS. However, the geometric mean particle size (GMPS) of the kernel-fraction that passes through the 4.75-mm sieve has not been well described. Therefore, the objectives of this study were (1) to evaluate particle size distribution and digestibility of kernels cut in varied particle sizes; (2) to propose a method to measure GMPS in WPCS kernels; and (3) to evaluate the relationship between CSPS and GMPS of the kernel fraction in WPCS. Composite samples of unfermented, dried kernels from 110 corn hybrids commonly used for silage production were kept whole (WH) or manually cut in 2, 4, 8, 16, 32 or 64 pieces (2P, 4P, 8P, 16P, 32P, and 64P, respectively). Dry sieving to determine GMPS, surface area, and particle size distribution using 9 sieves with nominal square apertures of 9.50, 6.70, 4.75, 3.35, 2.36, 1.70, 1.18, and 0.59mm and pan, as well as ruminal in situ dry matter (DM) digestibilities were performed for each kernel particle number treatment. Incubation times were 0, 3, 6, 12, and 24 h. The ruminal in situ DM disappearance of unfermented kernels increased with the reduction in particle size of corn kernels. Kernels kept whole had the lowest ruminal DM disappearance for all time points with maximum DM disappearance of 6.9% at 24 h and the greatest disappearance was observed for 64P, followed by 32P and 16P. Samples of WPCS (n=80) from 3 studies representing varied theoretical length of cut settings and processor types and settings were also evaluated. Each WPCS sample was divided in 2 and then dried at 60°C for 48 h. The CSPS was determined in duplicate on 1 of the split samples, whereas on the other split sample the kernel and stover fractions were separated using a hydrodynamic separation procedure. After separation, the kernel fraction was redried at 60°C for 48 h in a forced-air oven and dry sieved to determine GMPS and surface area. Linear relationships between CSPS from WPCS (n=80) and kernel fraction GMPS, surface area, and proportion passing through the 4.75-mm screen were poor. Strong quadratic relationships between proportion of kernel fraction passing through the 4.75-mm screen and kernel fraction GMPS and surface area were observed. These findings suggest that hydrodynamic separation and dry sieving of the kernel fraction may provide a better assessment of kernel breakage in WPCS than CSPS.