Fiber Particle Size Research Articles

Effect of level of fibre and type of grinding on the performance of rabbit does and their litters during the first three lactations

To study the effects of fibre level and particle size on rabbit performance, four diets in a 2 × 2 factorial arrangement were used with high (HF) and low (LF) fibre level (34 vs. 27% NDF, % DM) and coarse (CG) and normal (NG) type of grinding of the main sources of fibre (alfalfa hay and wheat straw). This resulted in a proportion of particles > 0.3 mm of 35, 24, 24 and 20% (on DM basis) for HF-CG, HF-NG, LF-CG and LF-NG diets, respectively. HF diets contained 4.2% pork lard to balance the digestible energy/protein ratios. Seventy two nulliparous rabbit does were randomly assigned to the diets (18 per diet) and controlled up to their fourth parturition. Remating interval was fixed at four days after parturition and weaning age at 25 days. Twenty does died or were culled during the experiment because of low prolificacy and infertility. CG diets reduced culling level from 22 to 2.8% ( P = 0.008) compared to NG diets. Digestible energy (DE) intake was not affected by treatments during lactation or among parturitions. However, an interaction NDF level × type of grinding was observed for feed and DE intake from weaning to parturition, as rabbit does fed HF-NG and LF-CG diets ate 10% more feed ( P = 0.040) and DE ( P = 0.053), and showed a shorter parturition-effective mating interval (− 5.3 days, P = 0.028) than those fed HF-CG and LF-NG. Animals fed LF-NG tended to have the lowest feed efficiency among parturitions ( P = 0.079). In rabbits fed LF, total milk production and litter growth rate from birth to 21 days decreased by 9% compared to those fed HF diets that included added fat ( P ≤ 0.013). Litters from rabbit does fed LF or NG diets increased ( P ≤ 0.040) their feed intake from 21 to 25 days, avoiding differences among treatments in litter weight gain during lactation. Post-weaning feed efficiency was less with LF diets ( P = 0.045). Thus, fineness of grinding of fibre sources should therefore be taken into account, especially in low fibre diets to optimize rabbit doe performance.

Viscoelastic properties of orange fiber enriched yogurt as a function of fiber dose, size and thermal treatment

The effect of orange fiber addition on yogurt viscoelastic properties was studied, the following factors were evaluated: (i) fiber doses (0, 0.2, 0.4, 0.6, 0.8 and 1 g/100 ml) (ii) fiber particle size (0.417–0.7 and 0.701–0.991 mm) (iii) fiber addition prior or after pasteurization. (i) In yogurts with pasteurized fiber G′, G″ and complex viscosity increased with fiber dose, whereas in non-pasteurized fiber yogurts smaller fiber particles (<0.4 g/100 ml) rheological parameters decreased due to the disruptive effect of the fiber, and over 0.6 g/100 ml rheological parameters increased. The presence of particles alters yogurt structure but when the fiber dose is high enough the water absorption compensates the weakening effect of the fiber. (ii) G′, G″ and viscosity were higher in yogurts with large particles than in yogurts with fiber of smaller size. The higher the number of fiber particles, the higher the disrupting effect. (iii) Fiber pasteurization in the mix enhances its integration in the gel matrix.

Removal of TDS from Cooling Tower Water by Using EDTA-Modified Bagasse Fibers

Modified by ethylenediaminetetraacetic acid (EDTA) salts and unmodified bagasse fibers were tested for the removal of total dissolved solids (TDSs) from cooling tower water. Parameters such as hydrogen ion concentration (pH), particle size of bagasse fibers, and the concentrations of adsorbent and adsorbate were studied to optimize the conditions to be applied on a commercial scale for the decontamination of effluents of cooling tower water. The optimum pH for TDS removal was between 6 and 6.5. The efficiency of TDS removal increased when the size of fiber particles decreased ( 100 μm ) and when the concentration of EDTA salt increased to reach 78 mg/g of modified bagasse fibers. The adsorption parameters were determined using both Langmuir and Freundlich isotherms. The preferential mechanisms for the retention of TDSs are a complexation process between the TDSs and chemical functions present on the surface of fibers, and the chelation process with the EDTA attached to the fibers. The results obtained cou...

Influence of insoluble fibre and whole wheat inclusion on the performance, digestive tract development and ileal microbiota profile of broiler chickens

1. An experiment of 21-d duration was conducted to examine the effects of diluting wheat-based diets with insoluble fibre sources and whole wheat inclusion on the performance, nutrient utilisation, digestive tract development and ileal microbiota profile of broiler chickens. The treatments were as follows: Treatment 1, control diet based on ground wheat; Treatment 2, where 200 g/kg whole wheat replaced the ground wheat pre-pelleting; and Treatments 3 and 4 where the control diet was diluted with fine cellulose and wood shavings, respectively, at a ratio of 6 : 100 (w/w). 2. Weight gains and apparent metabolisable energy were unaffected by dietary treatment. Gain : feed ratio was not influenced by the inclusion of whole wheat or wood shavings, but decreased with cellulose inclusion. However, when gain:feed of birds was corrected by subtracting the amount of cellulose and wood shavings from the total feed consumption, it was found that the inclusion of wood shavings increased gain : feed, while cellulose inclusion had no effect. Similarly, AMEN was unaffected by dietary treatment. However, when AMEN was corrected for energy contribution from cellulose or wood shavings, improvements in AMEN were observed in these two treatments. 3. Wood shavings increased the relative gizzard weights and improved ileal starch digestibility compared to other dietary treatments. All gut components were shorter in birds given diets containing cellulose and wood shavings compared to those receiving the control and whole wheat diets. 4. Ileal microbiota profiling, using denaturing gradient gel electrophoresis, showed that microbial composition was affected by dietary treatment and that the treatments were grouped into two main clusters. The two groupings showed similarity between birds receiving the control and cellulose diets and similarity between birds fed on the whole wheat and wood shavings diets. 5. The findings suggest that the effects of insoluble fibre on broiler performance differed depending on the fibre particle size.

Effects of the Chop Lengths of Alfalfa Silage and Oat Silage on Feed Intake, Milk Production, Feeding Behavior, and Rumen Fermentation of Dairy Cows

Effects of chop length (shorter: 6mm, or longer: 19mm) of alfalfa silage and oat silage were determined in 16 mid-lactation Holstein cows, 4 of which were rumen cannulated, using a replicated 4×4 Latin square design with a 2×2 arrangement of treatments. Experimental periods were 21 d long and consisted of 14 d of adaptation and 7 d of sampling. Cows received a total mixed ration containing [dry matter (DM) basis] 42.0% barley grain-based energy supplement, 10% protein supplement, and 24% of DM longer chop or shorter chop alfalfa silage and 24% of DM longer chop or shorter chop oat silage. Rumen pH was measured continuously, and rumen liquid flow rates were determined in rumen-cannulated cows. Feeding behavior was determined by videotaping, and meal patterns were determined by continuously weighing the feed in the bunk of 8 cows. Reducing the chop length of alfalfa silage and oat silage reduced the average geometric particle length from 14.2 to 10.9mm and from 13.4 to 10.4mm, respectively. Reducing the alfalfa chop length did not affect feed intake, whereas reducing the oat silage chop length increased DM intake from to 19.4 to 21.2 kg/d. Reducing the chop lengths of alfalfa silage and oat silage chop length did not affect milk production, rumen fermentation, feeding behavior, meal patterns, and blood metabolites. Daily milk yield, milk fat percentage, and milk protein percentage averaged 36.1 kg/d, 3.00%, and 3.16%, respectively, across diets. The low milk fat percentages suggest that the diets induced subacute ruminal acidosis. This was also substantiated by the rumen pH, which was below 5.6 for more than 122 min/d for all diets. The onset of subacute ruminal acidosis despite apparently adequate dietary neutral detergent fiber content and particle size distribution as well as the long duration of chewing might be attributed to sorting against long feed particles.

Effect of Yeast Culture on Efficiency of Nutrient Utilization for Milk Production and Impact on Fiber Digestibility and Fecal Particle Size

Approximately 260 Holstein cows on a commercial dairy were utilized in a switchback study. Treatments consisted of control or 56 g/d of yeast culture. The objectives of this experiment were to quantify the benefit of yeast culture on 1) efficiency of milk production, and 2) nutrient flows within the dairy system that utilizes a solids separator. Milk yield was recorded every 12 d. Pen feed intakes and refusals were recorded daily. Manure fiber particle size was determined from fecal grab samples via wet sieving. In addition, a mixture of feces plus water was sieved through a screen to replicate a manure solids separator. Cows receiving yeast culture showed numerically greater DMI (0.13 kg/d), an increase (P < 0.001) in BW gain, greater milk fat content (P < 0.02), greater (P < 0.08) milk fat yield, less milk protein content (P < 0.03), and similar milk protein yield (P > 0.05). Milk yields were similar between treatments; however, there was a trend for an increase (P < 0.19) in 3.5% fat corrected milk for cows fed yeast culture. Control cows had numerically lower NDF digestibility. Distribution of fecal particles suggests more manure solids may pass the manure solids separator to the manure lagoon and therefore reduce the amount of manure solids collected with the separator. Yeast culture was shown to impact nutrient use by the animal and affect manure particle partition.

Fermentation of plant cell walls by ruminal bacteria, protozoa and fungi and their interaction with fibre particle size

The objective of the experiment was to evaluate the contribution of various ruminal microbial groups to the fermentation of cell walls of corn stover with different particle sizes based on ruminal gas production in vitro. Physical, chemical, and antibiotical methods were used to differentiate groups of bacteria, protozoa and fungi in rumen fluid, offering following rumen microbial groups: whole rumen fluid (WRF), bacterial (B), protozoal (P), fungal (F), bacterial plus protozoal (B + P), bacterial plus fungal (B + F), protozoal plus fungal (P + F), and negative control (CON). Cell walls from corn stover were ground and ball milled to produce two different particle sizes. The results showed that digestion of the cell walls was undertaken by the interaction among ruminal bacteria, protozoa and fungi, and such co-actions seemed to fail alternation by one of three microbial groups or any combinations. However, B + P group showed a significant contribution to the degradation of milled cell walls, and B + F group revealed a great synergy effect on the ground cell walls degradation. Particle size of cell walls also had a considerable influence on their fermentation extent instead of the fermentative patterns by various rumen microbial groups.

Effect of filler content and size on the properties of ethylene vinyl acetate copolymer–wood fiber composites

AbstractIn this study, the main focus was on the effect of wood fiber (WF) content and particle size on the morphology and mechanical, thermal, and water‐absorption properties of uncompatibilized and ethylene glycidyl methacrylate copolymer (EGMA) compatibilized ethylene vinyl acetate copolymer–WF composites. For uncompatibilized composites, the tensile strength decreased with increasing WF content, whereas for compatibilized composites, the tensile strength initially decreased, but it increased for composites containing more than 5% WF. Small‐WF‐particle‐containing composites had higher tensile strengths than composites containing larger WF particles, both in the presence and absence of EGMA. WF particle size did not seem to have much influence on the degradation behavior of the composites, whereas water absorption by the composites seemed to be higher in composites with smaller particle sizes for both compatibilized and uncompatibilized composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3645–3654, 2007

Impact sound insulation and viscoelastic properties of underlay manufactured from recycled carpet waste

This paper reports an investigation of the impact sound insulation performance of a range of materials made from recycled carpet tiles and provides a comparison with the performance of some commercially available acoustic underlays. The impact testing is carried out using a specially designed rig. It is demonstrated that good quality acoustic materials can be successfully manufactured from a granulated mix of industrial carpet waste. The effects of the grain to fibre (G:F) mass ratio, binder concentration and particle size distribution on the acoustic performance is investigated. It is shown that the optimum G:F ratio should be close to the mass ratio of the backing material to the pile material in many types of commercial carpet tiles (60:40). Sieving the granular waste and producing samples containing a single class of particle size does not enhance the impact sound insulation performance. These are important findings, which should ensure an efficient, cost-effective, full-scale manufacturing process. A formulation has been developed which yields samples with optimum impact sound insulation capability. This optimised sample compares favourably with the commercial underlays tested on the impact rig. The dynamic mechanical properties of the developed underlays have also been investigated to provide a better understanding of their influence on the impact sound insulation.

Perfil granulométrico da fibra dietética sobre o tempo médio de retenção e a digestibilidade aparente de dietas para vacas leiteiras

Objetivou, com este experimento avaliar o efeito de diferentes tamanhos de partículas da fibra dietética sobre o tempo médio de retenção e a digestibilidade aparente de dietas para vacas leiteiras em lactação. Dez vacas holandesas com 550 kg de peso vivo médio foram distribuídas em um delineamento em switch back em três períodos consecutivos. Os animais foram estabulados individualmente e alimentados com rações em mistura completa, constituídas de feno de capim-Tifton (50,4%) e concentrado (49,6%). O feno foi triturado em moinho comercial com peneiras de malhas de 3,2; 4,8; 7,9; 15,9 e 25,4 mm. Amostras de cada moagem foram submetidas ao separador de partículas modelo Penn State, para determinação do perfil de distribuição das partículas de fibra. Constituiu-se cinco tratamentos: T1 - 100% das partículas abaixo de 8 mm; T2 - 76% abaixo de 8 mm e 24% entre 8 e 19 mm; T3 - 36,7% abaixo de 8 mm, 26,6% entre 8 e 19 mm e 36,7% acima de 19 mm; T4 - 32% abaixo de 8 mm, 28% entre 8 e 19 mm e 40% acima de 19 mm; T5 - 26% abaixo de 8 mm, 28% entre 8 e 19 mm e 46% acima de 19 mm. O perfil granulométrico exerceu efeito preponderante no trânsito das dietas, observando-se que aquelas com partículas de maior tamanho ficaram mais tempo no trato gastrintestinal. Os coeficientes de digestibilidade de matérias seca e orgânica foram maiores para dietas com menor granulometria comparativamente às de perfil mais grosseiro. Não houve efeito sobre as digestibilidades de proteína bruta e carboidratos não-fibrosos. A digestibilidade da fibra foi maior nas dietas com perfil mais fino. Os resultados sugerem que a granulometria da dieta pode ser determinante no tempo de retenção e na digestibilidade.

Effects of fiber content and particle size of forage on the flow of microbial amino acids from continuous culture fermenters.

Eight dual-flow continuous culture fermenters (1320 mL) were used in two 10-d consecutive periods to study the effects of fiber content and particle size on rumen fermentation, nutrient flow, and the profile and flow of amino acids (AA) from microbial origin. Treatments were arranged in a 2 x 2 factorial; the main factors were fiber content (high fiber [HF] = 67% alfalfa hay, 33% concentrate; low fiber [LF] = 39% alfalfa hay, 61% concentrate) and forage stem particle size (ground not to pass a 3-mm sieve = large size [LS]; ground to pass a 1-mm sieve = small size [SS]). On the last day of the experiment, liquid- (LAB) and solid- (SAB) associated bacteria were isolated from each fermenter for chemical analysis. Microbial N and AA flows were estimated using LAB or SAB composition data. Total volatile fatty acid concentration was higher for LF (122 mM) than for HF (102 mM). The proportion of acetate was higher for HF (63.5%) than for LF (58.2%). When SS was fed instead of LS, there was a reduction in the acetate proportion (63.4% vs 58.3%, respectively) and in the acetate to propionate ratio (3.13 vs. 2.41, respectively). Bacterial N flow was higher, and dietary N flow was lower, in SS compared with LS when LAB were used for calculations. Efficiency of microbial protein synthesis (EMPS) was affected by particle size, when LAB were used for calculations, and by fiber content, when SAB were used for calculations. The AA profile of LAB differed from SAB in 4 of 16 AA. The fiber content and particle size had small effects on microbial AA profile. However, the bacterial AA flow was higher in 13 of 16 AA, when SAB instead of LAB were used for calculations. Estimates of bacterial N flow, EMPS, AA profile, and flows of microbial origin were dependent on the type of microbial population used for calculations. The representativeness of the microbial samples is essential for the accurate prediction of the AA flow from microbial origin.

Effects of Neutral Detergent Fiber Concentration and Particle Size of the Diet on Chewing Activities of Dairy Cows

Six dry Holstein cows were used to evaluate the effect of dietary neutral detergent fiber (NDF) concentration and particle size (PS) on chewing activity. Treatments were arranged in a 3×3 factorial design; total mixed rations contained three NDF concentrations (26, 32, 38%) and three PS (1.0, 1.5, 2.0 cm). NDF levels and particle sizes of diets were adjusted by formulating rate and cutting length of alfalfa hay and rice straw. Cows were fed twice daily at 90% of ad libitum feed intake throughout the experiment. Chewing activity was positively associated with NDF concentration, but not significantly affected by PS of diet. Eating time per unit of NDF intake was affected by PS rather than NDF concentration of diet. Time spent ruminating per unit DM or NDF intake increased with increasing NDF concentration of diet, but was not affected by PS. As the PS of diet increased, the eating time per day increased, but the rumination time decreased. In addition, as the number of rumination bolues decreased the rumination duration increased as well as the chews per bolus. The regression equation induced from relationships of NDF concentrations (NDF, %) and particle sizes (PS, cm) of diet on roughage value index (RVI, min of chewing time/kg DMI) was as follows. RVI=-19.672+1.44×NDF+5.196×PS, (r 2 =0.81). (Asian- Aust. J. Anim. Sci. 2004. Vol 17, No. 11 : 1535-1540)

Preparation of high dietary fiber powder from lemon juice by-products

Lemon (Citrus limon cv Fino) juice industry by-products were used to obtain high dietary fiber powder. The effect of processing variables (direct drying, and washing previous to drying) on functional properties, fiber content and type, microbial quality and physicochemical properties of the fiber were evaluated. The obtained fiber powder had good functional, microbial quality and favorable physicochemical characteristics to be used in food formulations. Processing conditions affected fiber composition and properties. Water holding capacity was enhanced by washing (7 g water/g non-washed fiber powder; 12.6 g water/g washed fiber powder) and slightly decreased by the reduction in fiber particle size. Oil holding capacity (6.7 g oil/g fiber powder) was not affected by those factors. Acid detergent and neutral detergent fibers were highest in powder from washed lemon residue (23.73 and 32.91%, respectively). aw was lowest in washed lemon fiber powder (0.13). Washing prevented fiber browning during drying as reflected in color parameters. Washing water rinsed green components. Drying was the responsible for the decrease of bacterial populations (approx. 90% reduction in microbial counts).

Preparation of high dietary fiber powder from lemon juice by-products

Lemon ( Citrus limon cv Fino) juice industry by-products were used to obtain high dietary fiber powder. The effect of processing variables (direct drying, and washing previous to drying) on functional properties, fiber content and type, microbial quality and physicochemical properties of the fiber were evaluated. The obtained fiber powder had good functional, microbial quality and favorable physicochemical characteristics to be used in food formulations. Processing conditions affected fiber composition and properties. Water holding capacity was enhanced by washing (7 g water/g non-washed fiber powder; 12.6 g water/g washed fiber powder) and slightly decreased by the reduction in fiber particle size. Oil holding capacity (6.7 g oil/g fiber powder) was not affected by those factors. Acid detergent and neutral detergent fibers were highest in powder from washed lemon residue (23.73 and 32.91%, respectively). a w was lowest in washed lemon fiber powder (0.13). Washing prevented fiber browning during drying as reflected in color parameters. Washing water rinsed green components. Drying was the responsible for the decrease of bacterial populations (approx. 90% reduction in microbial counts).

Effect of Wheat Bran Fiber and Bran Particle Size on Fat and Fiber Digestibility and Gastrointestinal Tract Measurements in the Rat

ABSTRACTThe effect of wheat bran (AACC hard red) and bran particle size on fat and fiber digestibility and gastrointestinal tract measurements were investigated with diets containing 5.7–10.7% dietary fiber. Fifty‐six male weanling Sprague‐Dawley rats were randomly assigned to four diets containing 5% cellulose (C5); 10.5% cellulose (C10); 21.5% coarse (2 mm) wheat bran (CB); or 22.2% fine (0.5 mm) wheat bran (FB) in a sixweek study. Dietary fiber digestibilities were significantly different (P &lt; 0.05) among treatment diets (CB &gt; FB &gt; C5 &gt; C10) but there was no effect in fat digestibility among treatments. High‐fiber diets fed to rats resulted in significantly greater wet and dry fecal weights than low‐fiber diets. Bran diets resulted in significantly higher fecal moisture than cellulose diets. Cecum lengths increased significantly with bran diets compared with cellulose diets. The CB diet resulted in significantly higher stomach weights than with cellulose diets. Stomachs were heavier and cecal lengths were greater with bran diets than with cellulose diets; however, a high‐cellulose diet resulted in increased colon weight. Except for higher fiber digestibility of coarse bran, bran particle size had no significant effects. Healthful effects of wheat bran may be associated with gastrointestinal morphology and function. Fecal bulking and decreased intestinal transit time can prevent constipation and may dilute or reduce absorption of toxic or carcinogenic metabolites, thus improving gastrointestinal health and lowering the risk of tumor development and cancer.

Effects of fibre level and particle size on rumen microbial fermentation and protein metabolism using liquid and solid associated bacteria

The effects of fibre level (F) and forage particle size (S) on ruminal fermentation profile is often mediated through changes in feed intake, rates of digestion or passage, ruminal pH and/or bacteria population. Therefore, most in vivo studies have confounded the direct effect of F or S with changes in the rumen environment. In vitro systems allow to control several fermentation conditions independently (pH, flow rates, intake). Total, bacterial and dietary nitrogen (N) flows are generally calculated using liquid associated bacteria (LAB), although solid associated bacteria (SAB) represent about 80% of total bacterial population in the rumen (Olobobokun and Craig, 1988). The objective of this experiment was to study the effects of F and S on microbial fermentation and N metabolism using LAB or SAB values in a dual flow continuos culture system.

Stress-induced alignment of fibres in a particulate matrix

In this article, experimental evidence for the influence that steric interaction and orientational coupling have on the orientation of cellulose fibre dispersed in a particulate matrix is given. The filler coefficient of the fibre suspension is used as a probe to follow the average fibre orientation. It is shown that the fibres do not order into a nematic phase after numerous shear stress steps. From the evolution of the filler coefficient as a function of the time the stress was applied, a rate constant for reorientation was determined. Even in the dilute regime, its value depends on the fibre volume fraction. Results obtained with various fibre and particle sizes have been scaled onto a master curve, where it is shown that the rate of reorientation increases with the fibre–particle size ratio.

Breath Hydrogen and Methane Responses of Men and Women to Breads Made with White Flour or Whole Wheat Flours of Different Particle Sizes

Objective: While it is well known that consumption of whole grain foods results in beneficial health effects, the great majority of Americans prefer bread made with white flour. Consumption of whole grain foods in high fiber menus may cause undesirable intestinal responses. The purpose of this study was to determine whether consumption of bread made with ultra fine ground whole wheat flour retained beneficial effects while reducing undesirable effects.Methods: Twenty-six men and women (31 to 55 years of age) consumed glucose solutions or bread made with white, whole wheat or fine ground whole wheat flour (1 g carbohydrate/kg body weight) in a Latin square design after two days of controlled diet. Breath methane and hydrogen were determined over the 24 hours after consumption of test foods.Results: Hydrogen and methane responses of men and women were similar. There were no significant differences in methane responses to the different treatments, but hydrogen response was increased by all breads (p<0.0001). Although the overall mean response values were similar for all three breads, the patterns of hydrogen response differed (treatment*time, p<0.003). Gastrointestinal symptoms were not associated with fiber content or particle size of bread; however, subjects reporting symptoms tended to have higher methane responses (0.05<p<0.10).Conclusion: Neither fiber content of bread nor particle size of whole wheat flour substantially affected breath hydrogen or methane responses or gastrointestinal symptoms. Fine ground whole wheat breads may provide a more acceptable food choice than standard whole wheat bread without sacrificing the beneficial health effects of higher fiber.

Pressure infiltration of sol/gel processed short fibre ceramic matrix composites

Using pressure infiltration short fibre-reinforced ceramic matrix composites with uniform and dense microstructure can be made. Based upon this processing technique, composites composed of silica sol, alumina particles, and alumina short fibres were fabricated. The related processing parameters studied in this work include infiltration rate, fibre volume fraction Vf, particle size, and infiltrate viscosity. An optimal infiltration rate was 4 mm min-1, at which rate the composite with Vf of 8.1% and particle size of 3 μm has the highest green density. An equilibrium between particle packing strength and applied load must be obtained during the infiltration to obtain high green density and composite strength. The influence of fibre volume fraction and particle size on composite green density is in a synergistic manner because it involves particle–fibre interactions, fibre–fibre interactions, and sedimentation. Furthermore, the increase of sol viscosity results in more sedimentation in the infiltrate and lower composite green density. The fracture toughness of composites is 38% higher than that of monolithic alumina. © 1998 Chapman & Hall

Intake Limitations, Feeding Behavior, and Rumen Function of Cows Challenged with Rumen Fill from Dietary Fiber or Inert Bulk

Twelve multiparous, rumen, cannulated cows (17 DIM) were fed 25 or 35% NDF diets without or with added rumen-inert bulk as water-filled plastic containers (500ml each) within three 4 × 4 Latin squares (21-d periods). Added bulk equaled 25% of pretrial rumen volume for each cow. Objectives were to challenge cows with rumen fill in the form of dietary NDF and inert bulk to determine whether bulk affects intake similarly for diets of different NDF content of whether changes in behavior or rumen function allow cows to adapt to higher fill. Inert bulk had no effect on DMI for cows fed 25% NDF but decreased DMI for cows fed 35% NDF (18.7 vs. 16.6 kg/d). Volume of rumen digesta plus inert bulk, 102L, was similar for 35% NDF treatment regardless of presence or absence inert bulk. Additional NDF or inert bulk increased the number of ruminating bouts per day, chewing time per unit of DMI or NDF intake, frequency of reticular contractions during rumination, and fractional passage rate of NDF from the rumen. Although these changes may help to alleviate fill, they were insufficient to maintain intake under conditions of high fill. Intake by cows receiving high fiber diets can be limited by reticulorumen capacity. Future study is required to determine the effect of rumen fiber digestion, fiber particle size, and animal characteristics on fill-limited intake.