Greater Neutral Detergent Fiber Digestibility Research Articles

Intrinsic and Extrinsic Factors Affecting Neutral Detergent Fiber (NDF) Digestibility of Vegetative Tissues in Corn for Silage

Dairy farming requires forages with high neutral detergent fiber (NDF) to maximize milk production, sustain cows’ health, and ensure the economic and environmental sustainability of the dairy farm. The objectives of this study were to determine the effects of the brown midrib (BMR) genotype, agronomic environment, and maturity at harvest on the NDF digestibility (NDFD) and the composition of the cell wall of corn plant tissues. In this plot study, one conventional and one BMR corn hybrid were planted and subjected to an abundant (60,000 seeds/ha and 225 kg N/ha) and a limited (90,000 seeds/ha and 180 kg N/ha) environment. The ruminal NDFD was determined in vitro in leaf blades, leaf sheaths, and stem internodes. Cell walls from BMR corn had greater NDFD than cell walls from conventional corn on most tissues. Relative to the abundant environment, the limited environment had minimal effects on NDFD. As maturity advanced, NDFD decreased for various but not all tissues. In conclusion, under the conditions of this study, intrinsic characteristics of corn, such as genotype and maturity at harvest, had a greater effect on NDFD than environment or agronomic management.

196 Interaction of Corn Processing Method and Sweet Bran Inclusion in Finishing Diets

Abstract Two studies were conducted to evaluate the effect of corn processing method and wet corn gluten feed [Sweet Bran (SB); Cargill] concentration on feedlot performance and nutrient digestion. Treatments were arranged as a 2 × 3 factorial, consisting of two corn processing methods [steam-flaked corn (SFC) or a high-moisture corn (HMC) dry-rolled corn (DRC) blend] and 3 inclusions of SB (0, 20, or 40% of diet dry matter). In Exp. 1, yearling steers (n = 480; initial body weight = 363 ± 15.1 kg) were utilized in a randomized block design. A linear interaction was observed for average daily gain (ADG), feed efficiency (G:F), and hot carcass weight (HCW; P < 0.01). At 0% SB, cattle fed SFC had greater ADG and HCW than cattle fed HMC/DRC. As SB increased, ADG and HCW increased at a greater rate for HMC/DRC cattle than SFC cattle resulting in similar ADG and HCW at 40% SB. At 0% SB, cattle fed SFC were 12.4% more efficient than cattle fed HMC/DRC, but as SB increased the improvement declined to 5.3%. In Exp. 2, 6 fistulated steers were utilized in a 6 × 6 Latin square design. Cattle fed SFC had greater starch digestibility (P < 0.01); HMC/DRC cattle tended to have greater neutral detergent fiber digestibility (P = 0.08). As SB increased, cattle fed SFC and HMC/DRC had greater dry matter intakes (DMI) in both studies (P > 0.01), and as a result, greater digestible energy (DE) intakes (P > 0.01). Increased DE intake improved ADG and G:F when feeding SB in Exp. 1 as explained by greater DMI and increased DE observed in Exp. 2. Feeding up to 40% SB in SFC diets doesn't affect feedlot performance and feeding SB in HMC/DRC based finishing diets linearly improves performance at inclusions up to 40%.

Impacts of Rumen Degradable or Undegradable Protein Supplementation with or without Salt on Nutrient Digestion, and VFA Concentrations.

Simple SummaryRuminant animals have two specific protein requirements: the protein required by the animal, and the protein required by the microorganisms that exist within the rumen of the animal. These requirements are satisfied by rumen undegradable (RUP) and rumen degradable protein (RDP), respectively. Within the rumen, RDP is hydrolyzed, while RUP is digested and absorbed in the small intestine. As these proteins are digested differently, we studied their impact on the digestion process of low-quality forage. Overall, we found that a RDP supplement, when fed in a self-fed form, may enhance the digestion and use of low-quality forages. This may assist producers in selecting supplementation programs for their operation. The objectives of this study were to evaluate the effect of differences in protein type and delivery method on rumen dynamics and nutrient digestion. Cows were allotted to rumen degradable protein (RDP) or rumen undegradable protein (RUP) and self-fed (SF) salt-limited pressed blocks or hand-fed (HF) loose supplement, resulting in four dietary treatments. There was a delivery effect (p = 0.04) on neutral detergent fiber (NDF) intake, as the SF animals consumed more NDF than HF animals. The RDP-SF animals had greater NDF digestibility (p = 0.04) and water intake (p = 0.03) than the three other treatments. Supplement intake displayed a protein type effect (p = 0.03), as RDP-supplemented animals consumed more supplement on a g·kg body weight (BW)−1 d−1 basis than RUP animals. There was an effect of protein type (p = 0.02) and delivery method (p = 0.03) on fluid flow rate, with RUP and HF cows having greater liquid flow rates. Ruminal pH was lower (p < 0.01) in RDP-HF cows than RDP-SF cows at all hours, except 4-h post-feeding. RDP-SF animals had the greatest (p < 0.01) concentrations of ruminal ammonia. Valerate ruminal concentrations were greater (p = 0.04) in RDP supplemented animals compared to RUP supplemented animals. In conclusion, self-fed supplements containing RDP may enhance the use of low-quality forages and increase ruminal ammonia concentrations.

Fractional Harvest of Fodder Galega for Improved Herbage Nutritive Value

Fodder galega (Galega orientalis Lam.) is a long-lived perennial legume grown for forage and green manure in northern and central Europe. It is distinguished by a high proportion of leaves in the aboveground mass, tall hollow stems, and rhizomes. A method to harvest galega allowing the separation of leaves, upper stem fragments, and inflorescences from the thick, woody parts of the stem is therefore justified. This would significantly expand the possibilities of using galega herbage, including as feed for monogastric animals. A modified flail chopper (MFC), a machine originally used for harvesting green forage, was used for the fractionated harvest of galega. The aim of this study was to evaluate the yield potential of various plant fractions of the first and second cut of fodder galega at three development stages and their nutritive value when harvested with an MFC. With this harvest system, 68–78% of the potential dry matter yield of galega was harvested, where leaves accounted for 73% of the dry matter on average, while the proportion of leaves in the yield of galega harvested with a mower (M) ranged from 50% to 60%. In the biomass of the first cut of galega, harvested with the MFC, protein concentration was 215 g kg−1, 11.5% greater than in the biomass of the whole aboveground mass harvested with a mower. In the second cut, this difference, in favor of the MCF, was greater by 14%. The concentration of neutral detergent fiber (NDF) was 7.5% lower and acid detergent fiber 11% lower in galega forage harvested with the MFC compared to with a mower. Furthermore, galega harvested with MFC had 13% greater NDF digestibility and 6% greater in vitro true digestibility. The stubble remaining after MFC harvest accounted for 33% of the total height and 27% of the plant dry mass, and its qualitative composition indicates that it could be used in rations of livestock with low nutritional requirements or for non-forage purposes. Galega harvest with the MFC resulted in greater protein concentrations and overall improved nutritive value of the forage even at advanced development stages.

Fermentation characteristics and nutritive value of baled grass silages made from meadow fescue, tall fescue, or an orchardgrass cultivar exhibiting a unique nonflowering growth response

Throughout central Wisconsin, many soils are poorly drained, and perennial cool-season grasses are often planted as monocultures or in mixed stands with alfalfa because of the poor persistence of alfalfa under these growing conditions. Our objectives were to compare the fermentation characteristics and nutritive value of perennial cool-season grasses {meadow fescue [Schedonorus pratensis (Huds.) P. Beauv.], orchardgrass (Dactylis glomerata L.), and endophyte-free tall fescue [Schedonorus phoenix (Scop.) Holub]} conserved as baled silages with or without particle-size reduction, and at 2 moisture concentrations. Twenty-four plots (0.23 ha) were arranged in a randomized complete block design with 6 plots/block. Within each of the 4 field blocks, one of the 6 plots was assigned randomly to each of the (3 × 2) factorial combinations of forage type and bale cutting engagement (cut or uncut). The baler cutting mechanism consisted of 15 cutting knives, thereby creating a theoretical length of cut of about 8.1 cm. Generally, sufficient forage was available to produce 2 bales/plot; therefore, one bale was packaged at relatively high moisture (58.3%), whereas the other bale was made at an ideal moisture (44.9%) for this silage preservation method. Theoretically, bale cutting can increase bale weights and densities by reducing particle size, thereby allowing inclusion of additional forage within the same-sized bale. In this experiment, bale-cutting within 1.2 × 1.2 m silage bales (n = 47) increased initial wet and dry bale weights by 4.1 and 4.7%, respectively, but had no practical effect on measures of nutritive value, either on a pre- or postensiled basis. Cutter engagement tended to increase total volatile fatty acids in silages, thereby resulting in a pH reduction of 0.07 pH units (5.54 vs. 5.61). A unique nonflowering growth response by the first-cutting orchardgrass forage resulted in yields of dry matter for orchardgrass (2,977 kg of dry matter/ha) that were only 52 to 53% of those observed for meadow (5,580 kg of dry matter/ha) or tall fescue (5,763 kg of dry matter/ha), which did not differ. Despite the unique vegetative nature of orchardgrass, concentrations of neutral detergent fiber, acid detergent fiber, and acid detergent lignin determined before ensiling exhibited limited variability across forages (60.9 to 62.7%, 35.2 to 36.4%, and 2.75 to 2.99%, respectively). However, a 30-h in vitro incubation determined that orchardgrass exhibited greater neutral detergent fiber digestibility (56.2%) compared with meadow (44.9%) or tall fescue (40.8%), which were also statistically distinct.

Foliar fungicide application effects on whole plant BMR and floury corn varieties, and whole plant corn silage composition

The objective of this study was to determine the effects of foliar fungicide (FUN; Headline AMP; BASF Corp., applied at vegetative tassel growth stage) and ensiling time (0, 30, 90, 150 d) on fiber composition of 2 corn varieties (brown midrib; BMR and floury; FLY). Treatments were assigned to 16 3.38-ha plots in a completely randomized split-plot block design. Treatments were: BMR without FUN, FLY without FUN, BMR with FUN, and FLY with FUN. Samples of whole corn plants were collected and separated into leaves, stalks, flag leaf (FL), and cobs. Fresh-cut, whole-plant corn silage (WPCS) samples were collected at harvest and sealed inside mini silos for the duration of their respective ensiling times. Statistical analysis was performed using the MIXED procedure in SAS (v9.4). Brown midrib corn plants had a greater number of green leaves than FLY with 11.81 and 11.34 ± 0.09 leaves, respectively (P = 0.001). Corn plants in control (BMR without FUN and FLY without FUN; CON) had a greater number of yellow leaves than FUN corn plants with 0.28 and 0.08 ± 0.02, respectively (P < 0.0001). Corn treated with FUN tended to yield more WPSC than CON with 63,634 and 60,488 ± 1533 kg/ha, respectively (P = 0.08). Whole plant corn silage acid detergent lignin (ADL) content decreased as days ensiled increased with 31.61, 28.48, 25.48, and 22.38 ± 0.77 g/kg of DM for 0, 30, 90, and 150 d, respectively (P < 0.0001). Floury WPSC had a greater ADL content than BMR WPSC with 31.25 and 22.72 ± 0.61 g/kg of DM, respectively (P < 0.0001). Brown mid-rib WPSC had a greater neutral detergent fiber digestibility at 30 h (NDFD30) than FLY WPSC with 572.6 and 492.3 ± 6.9 g/kg of DM, respectively (P < 0.0001). Floury WPSC had greater undigested NDF (uNDF) than BMR WPSC with 125.3 and 96.1 ± 2.1 g/kg of DM, respectively (P < 0.0001). Brown mid-rib corn kernels had a greater kernel vitreousness than FLY corn kernels with scores of 3.11 and 2.65 ± 0.13, respectively (P = 0.05). A variety × treatment interaction was observed for kernel vitreousness score with scores of 3.23, 2.99, 2.49, and 2.80 ± 0.14 for BMR/CON, BMR/FUN, FLY/CON, and FLY/FUN, respectively (P < 0.0001). In conclusion, BMR treated with FUN and ensiled for 90–150 d yielded the best WPCS for feeding to dairy cows.

Forage Accumulation and Nutritive Value of Reduced Lignin and Reference Alfalfa Cultivars

Core Ideas Reduced lignin and reference cultivars did not differ in forage accumulation. Forage accumulation was greater with a fall harvest or a 40‐d cutting schedule. Reduced lignin alfalfa averaged 8% less acid detergent lignin and 10% greater neutral detergent fiber digestibility. Cutting treatments with shorter harvest intervals increased forage nutritive value. Delaying reduced lignin alfalfa harvest increased forage mass and maintained quality. Reduced lignin alfalfa (Medicago sativa L.) cultivars have the potential to increase the feeding value of alfalfa for livestock by improving forage fiber digestibility and to increase harvest management flexibility. The objectives were to compare the forage accumulation and nutritive value of reduced lignin and reference alfalfa cultivars when subject to diverse cutting treatments in the establishment and first production year. Research was established in 2015 at four locations in Minnesota. Reference alfalfa cultivars 54R02, DKA43–22RR, WL 355.RR, and the reduced lignin cultivar 54HVX41 were subject to cutting treatments with variable intervals between harvests. Cultivar by cutting treatment interactions were not significant (P &gt; 0.05), but cultivar and cutting treatment effects were significant. Cultivars did not consistently differ in forage accumulation. Establishment year forage accumulation was greater when a fall harvest was taken, and first production year forage accumulation was generally greatest when alfalfa was harvested on a 40‐d cutting schedule. Compared to reference alfalfa cultivars, 54HVX41 had an average of 8% less acid detergent lignin (ADL) and 10% greater neutral detergent fiber digestibility (NDFD) but was similar in crude protein (CP) and neutral detergent fiber (NDF) concentrations. Cutting treatments with shorter harvest intervals increased forage CP and NDFD and decreased NDF and ADL concentrations. With a 5‐d harvest delay, 54HVX41 harvested on a 35‐d harvest interval had a 21% gain in forage mass and a 3% reduction in relative forage quality (RFQ) compared to reference cultivars harvested on a 30‐d harvest interval, which could allow for increased management flexibility.

Screening exogenous fibrolytic enzyme preparations for improved in vitro digestibility of bermudagrass haylage

Our objectives were to evaluate the effects of 12 exogenous fibrolytic enzyme products (EFE) on ruminal in vitro neutral detergent fiber digestibility (NDFD) and preingestive hydrolysis of a 4-wk regrowth of bermudagrass haylage (BH), to examine the accuracy of predicting NDFD with EFE activity measures, and to examine the protein composition of the most and least effective EFE at increasing NDFD. In experiment 1, effects of 12 EFE on NDFD of BH were tested. Enzymes were applied in quadruplicate to culture tubes containing ground BH. The suspension was incubated for 24 h at 25°C before addition of rumen fluid media and further incubation for 24 h at 39°C. The experiment was repeated twice. In addition, regression relationships between EFE activity measures and NDFD were examined. Compared with the values for the control, 9 EFE-treated substrates had greater NDFD (37.8 to 40.4 vs. 35.6%), 6 had greater total VFA concentration (59.1 to 61.2 vs. 55.4 mM), and 4 had lower acetate-to-propionate ratios (3.03 to 3.16 vs. 3.24). In experiment 2, EFE effects on preingestive fiber hydrolysis were evaluated by incubating enzyme-treated and untreated bermudagrass suspensions in quadruplicate for 24 h at 25°C and examining fiber hydrolysis measures. Compared with values for the control, 3 EFE reduced neutral detergent fiber concentration (62.8 to 63.7 vs. 67.3%), 10 increased release of water-soluble carbohydrates (26.8 to 58.5 vs. 22.8 mg/g), and 8 increased release of ferulic acid (210 to 391 vs. 198μg/g). Regression analyses revealed that enzyme activities accurately [coefficient of determination (R2)=0.98] predicted preingestive hydrolysis measures (water-soluble carbohydrates, ferulic acid), moderately (R2=0.47) predicted neutral detergent fiber hydrolysis, but poorly (R2≤0.1) predicted dry matter and NDFD. In experiment 3, proteomic tools were used to examine the protein composition of the most and least effective EFE at improving NDFD. Relative to the least effective, the most effective EFE at increasing NDFD contained 10 times more endoglucanase III, 17 times more acetylxylan esterase with a cellulose-binding domain 1, 33 times more xylanase III, 25 times more β-xylosidase, and 7.7 times more polysaccharide monooxygenase with cellulose-binding domain 1 and 3 times more swollenin. The most effective EFE had a much greater quantity of fibrolytic enzymes and key proteins necessary for hemicellulose and lignocellulase deconstruction. This study identified several EFE that increased the NDFD and in vitro fermentation of 4-wk BH and revealed why some EFE are more effective than others.

Sugar Yield of Sweet Pearl Millet and Sweet Sorghum as Influenced by Harvest Dates and Delays Between Biomass Chopping and Pressing

Bagasse remaining after extracting the juice from crop biomass for ethanol production could be preserved as silage and used in animal feedstock, but the nutritive and conservation attributes of bagasse silage from sweet sorghum (Sorghum bicolor (L.) Moench) and sweet pearl millet (Pennisetum glaucum (L.) R.Br) are not well known. We evaluated the nutritive and conservation attributes of silages made with the bagasse of two species (sweet pearl millet and sweet sorghum) harvested on two dates (August and September) at two sites in Quebec (Canada) and ensiled after four delays between biomass chopping and pressing (0.5, 2, 4, and 6 h). Bagasse silages made in laboratory silos were considered well preserved (pH ≤ 4.0, NH3-N 30 g kg−1 DM, no propionic and butyric acids) regardless of species, harvest date, or delay between biomass chopping and pressing. Sweet pearl millet and sweet sorghum bagasse silages had similar total N concentration, in vitro true digestibility of dry matter (IVTD), and in vitro neutral detergent fiber digestibility (NDFD). Bagasse silage made from biomass harvested in August rather than in September had a 4 % greater concentration of total N, a 4 % greater IVTD, and a 8 % greater NDFD. The delay between biomass chopping and pressing did not affect the nutritive and conservation attributes of silages. Juice extraction from the biomass of sweet pearl millet and sweet sorghum did not impair attributes of good silage fermentation but it reduced its nutritive value.

Sparse‐Flowering Orchardgrass Represents an Improvement in Forage Quality During Reproductive Growth

ABSTRACTOrchardgrass (Dactylis glomerata L.) is a major component of many pastures in temperate North America. Early and profuse flowering in pastures is problematic, because livestock refuse to consume flowering stems, prompting many graziers to simply avoid using this species. The objective of this research was to determine the impact of reduced flowering on the quality of harvested forage under two harvest managements of orchardgrass. Six cultivars, three normal cultivars and three sparse‐flowering cultivars (mean panicle density of 141 vs. 61 panicles m⁻2, respectively), were evaluated in field experiments at 21 locations in North America under a 3‐cut harvest management. These cultivars were also evaluated at seven locations under a 5‐cut harvest management. Sparse‐flowering cultivars averaged 9% greater crude protein (CP), 3% lower neutral detergent fiber (NDF), 2% greater NDF digestibility, and 2% greater in vitro dry matter digestibility (IVDMD) than normal cultivars. For the two digestibility measures, differential panicle density between the cultivar groups explained a significant portion of variability, indicating that the increase in forage quality was proportional to the decrease in panicle density below a threshold of about 50 panicles m⁻2. Lastly, differences in regrowth forage quality between cultivar groups were smaller, less consistent, and of lesser statistical significance than for first harvest. While selection for sparse flowering in orchardgrass resulted in significant cause‐and‐effect increases in first‐harvest forage quality, these effects were too small to offset the reduced forage yield associated with the sparse‐flowering trait.

Effects of Saccharomyces cerevisiae and monensin on digestion, ruminal parameters, and balance of nitrogenous compounds of beef cattle fed diets with different starch concentrations

This study was carried out aiming to evaluate the effects of yeast or monensin supplementation on dry matter intake, nutrients digestibility, ruminal volatile fatty acids profile, ruminal pH and ammonia concentration, microbial protein synthesis, and the balance of nitrogen compounds of cattle fed high concentrate diet (80 % dry matter (DM) basis) with two different levels of starch. Eight crossbred beef steers fitted with rumen cannula were assigned to two simultaneous 4 × 4 Latin squares arranged in a 4 × 2 factorial design. Two different starch levels (23 and 38 % of DM) were assigned to each Latin square, independently. Within each Latin square, four treatments were randomly assigned to the experimental animals (control; monensin; 1-g yeast [1 g/100 kg body weight (BW)/day] treatment; and 2.5-g yeast [2.5 g/100 kg BW/day] treatment). Feed additives did not influence ruminal pH (P > 0.05). Total ruminal volatile fatty acids (VFA) concentration was greater (P<0.05) in the diet with the lowest starch level. Similarly, monensin and 1-g yeast treatments resulted in greater (P<0.05) VFA concentration in the rumen. Monensin inclusion in the diet with the highest starch level led to a decrease (P<0.05) in lactate concentration in the rumen. However, acetate levels were increased (P<0.05) by the inclusion of 1 g of yeast in the diet with lowest starch level. Ruminal concentrations of propionate and butyrate, and ammonia-N were not influenced (P>0.05) by none of the additives evaluated. However, propionate concentration was greater (P<0.05) in the low-starch diets. Low-starch diets resulted in lower ruminal ammonia-N concentration and greater neutral detergent fiber digestibility (P<0.05). The excretion of urinary nitrogenous compounds, purine derivatives, synthesis of microbial protein, microbial efficiency, and balance of nitrogenous compounds were not affected by treatments evaluated (P>0.05). Monensin or yeast inclusion in high concentrate beef cattle diets in tropical regions as in Brazil is not justified by do not alter nutrient digestibility, nitrogen balance, and main ruminal parameters.

Milk production and nutrient digestibility by dairy cows when fed exogenous amylase with coarsely ground dry corn

The digestibility of starch provided by coarsely ground corn is often low, which reduces the digestible energy (DE) concentration of the diet. We hypothesized that adding exogenous amylase to diets based on coarsely ground dent corn would increase dietary DE resulting in greater milk production. Total-tract nutrient digestibility was measured in a partially replicated Latin square experiment (6 cows and 4 periods) with a 2 × 2 factorial arrangement of treatments. Diets had 26 or 31% starch with or without exogenous amylase (amylase was added to the concentrate mixes at the feed mill). In the low and high starch diets, coarsely ground dry corn (mean particle size=1.42mm) provided 43 and 62% of total dietary starch (corn silage provided most of the remaining starch). No treatment interactions were observed. High starch diets had greater dry matter (DM), organic matter, and energy digestibility than low starch diets, and diets with amylase had greater neutral detergent fiber digestibility than diets without amylase. Digestibility of starch averaged 88% and was not affected by treatment. A long-term (98-d) lactation study with 48 Holstein cows (74 d in milk) was conducted using 3 of the diets (low starch diets with and without amylase and the high starch diet without amylase). Addition of amylase to a diet with 26% starch did not affect intake, milk yield, milk composition, body weight, or body condition. Cows fed the diet with 31% starch had greater DM and DE intakes; yields of milk, fat, and protein; and feed efficiency than those fed diets with 26% starch. Milk composition was not affected by starch concentration. Adding exogenous amylase to a lower starch diet did not make the diet nutritionally equivalent to a higher starch diet.

Fermentative characteristics of cereal brans and vegetable fibers

Dietary fiber has been suggested to alter the colonic environment and protect against colorectal diseases, but several recent epidemiological studies indicate that cereal and vegetable fibers may not confer the same benefit. To address this issue, five common cereal brans (barley, corn, oat, rice, and wheat) and five vegetable fiber isolates (broccoli, cabbage, carrot, cauliflower, and lettuce) were fermented in vitro with human fecal microbiota for 4, 8, 12, and 24 hours. Short-chain fatty acid (SCFA), hydrogen (H2), and methane (CH4) productions and neutral-detergent fiber (NDF) digestibility differed significantly with fiber source. The vegetable fibers were significantly more fermentable than were the cereal brans, as evidenced by greater NDF digestibility and increased productions of SCFA, H2, and CH4, despite the presence of fermentable starch and protein in the latter. We concluded that vegetable fibers may more effectively stimulate colonic fermentation than cereal brans do. These findings suggest an attribute (i.e., fermentability) that may partially explain previously observed differences between vegetable and cereal fiber consumption patterns and colorectal carcinogenesis.