Higher Neutral Detergent Fiber Digestibility Research Articles

Evaluation of meadow fescue grass cultivars seeded with alfalfa in New York state

AbstractAlfalfa–grass mixtures sown in the northeastern United States provide high‐quality dairy forage, and meadow fescue (Festuca pratensis Huds.) may improve the quality of these mixtures. Our objectives were to evaluate competitiveness and nutritive value of nine meadow fescue (MF) cultivars in New York State at spring harvest. Three farms, two in central New York State and one in northern New York state, were used. Conventional alfalfa (Medicago sativa L.) was sown (15 lb acre−1) to nine MF cultivars (three tetraploid and six diploid) and one tall fescue Lolium arundinaceum (Schreb.) ‘Darbysh’ cultivar in a randomized complete block design with four field replicates at each field site at three seeding rates (1, 2, and 3 lb acre−1). Grass proportion in mixtures was estimated visually. Grass samples were collected shortly before first harvest and analyzed for neutral detergent fiber, neutral detergent fiber digestibility (NDFD), acid detergent fiber, in vitro digestibility, and crude protein. Most meadow fescue cultivars maintained a grass proportion between 20%–45% across farms and growing seasons when seeded at 1lb acre−1. Seeding rates above 1lb acre−1 resulted in grass proportions above the recommended 20–30% grass proportion rate. Drought in early 2022 resulted in an average drop in grass percentage of 16.9% units for meadow fescue in mixtures, compared to 2021. Nutritive value of cultivars varied among farms and over growing seasons. Meadow fescue cultivars averaged 2.7% units higher NDFD than tall fescue, and cultivars with consistently high NDFD were Hidden Valley, SW Revansch, SW Minto, and Schwetra. Tetraploid cultivars averaged 4.0% units lower NDF compared to diploid cultivars, which is very advantageous for grass in alfalfa–grass mixtures.

Dynamics and plasticity of agronomic performance and nutritive quality traits in forage maize at high latitudes

The relationships between dynamics and plasticity (ability of a hybrid to modulate its traits according to growing conditions) of agronomic and nutritional traits are unclear. Quantifying and characterizing these relationships can improve understanding of plant response mechanisms to growing conditions in short cropping periods at high latitudes. This study investigated the dynamics of key agronomic performance and forage quality traits and the importance of their mean values for expression of plasticity. Data were collected on eight sampling occasions during the cropping period in 2013 and 2014, using six phenologically different forage maize hybrids grown at three high-latitude locations. The dynamics of all traits studies were significantly affected by hybrid and environment (combination of location and year). Dry matter yield (DMY) and dry matter content (DM) were affected by interactions between hybrid, growing conditions on each sampling occasion, and overall growing conditions in the different environments. Neutral detergent fiber digestibility (NDFD), starch (STA) concentration, water-soluble carbohydrate (WSC) concentration, and organic matter digestibility (OMD) in the hybrids differed significantly over time across the environments. Early-maturing hybrids progressed faster in maturity based on DM content and had higher STA concentration, NDFD, and OMD at a given time than later-maturing hybrids. Similar DMY and higher NDFD and OMD in early-maturing compared with later-maturing hybrids, regardless of sampling occasion or environment, suggests that use of early-maturing hybrids is advantageous in the short cropping season at high latitudes. For most traits, plastic ability [plasticity of trait x/mean value of trait x, or ability to change expression of plasticity of a trait is based on the mean value of the trait] was dependent on the mean value of a trait and declined with increasing mean value. Plastic ability of DM, DMY and STA was higher at early developmental stages and decreased at later developmental stages, but the opposite was true for WSC and CP. Although the dynamics of trait development over time differed between the hybrids, the dynamics of plastic ability for four traits (DM, WSC, OMD, NDF) were similar in all hybrids. These maturity characteristics-based responses of the six hybrids in terms of trait dynamics and plastic ability, and the dependence of plastic ability on the dynamics of corresponding trait, can potentially be exploited in development of new variety/hybrid and prediction models for further improving the agronomic and nutritional value of forage maize crops at high latitudes.

Effect of sugarcane fiber digestibility, conservation method and concentrate level on the ruminal ecosystem of beef cattle

The aim of this study was to investigate the effects of sugarcane neutral detergent fiber digestibility (NDFD), conservation method, and concentrate level on the ruminal microbial population of steers. Eight ruminal-cannulated Nellore steers were distributed in two contemporary 4 × 4 Latin Square design with a 2 × 2 factorial arrangement of treatments. Experiment 1: diets were formulated with 60% of concentrate level, and two sugarcane genotypes (high or low NDFD) either freshly cut or as silage. Experiment 2: diets were formulated with two levels of concentrate (60 or 80%), and two sugarcane genotypes (high or low NDFD) offered as freshly cut. Each experimental period lasted for 14 d, with the last 4 d used for ruminal fluid collection. Three cellulolytic bacteria (Fibrobacter succinogenes, Ruminococcus albus, Ruminococcus flavefaciens), two amylolytic (Streptococcus bovis, Ruminobacter amylophilus), and a lactate fermenting microorganism (Megasphaera elsdenii) were quantified by qPCR. Experiment 1: diets with fresh sugarcane increased the population of S. bovis, and M. elsdenii. Sugarcane with high NDFD increased F. succinogenes population only when sugarcane was offered as freshly cut. Experiment 2: increasing concentrate in the diet decreased S. bovis population, and increased R. amylophilus. Sugarcane with high NDFD increased the population of cellulolytic bacteria only at the 60% concentrate diet. Providing sugarcane with high NDFD favored the growth of fibrolytic bacteria, and this effect were dependent on the conservation method and on diet concentrate level. In addition, sucrose appears to have great effect on the composition of ruminal microflora, especially S. bovis.

Ensiling barley cultivars selected for varied levels of in vitro neutral detergent fiber digestibility in mini- and bunker-silos to evaluate effects on fermentation.

Thirty hour in vitro neutral detergent fiber digestibility (NDFD) of three barley cultivars such as ‘CDC Cowboy’ [high-neutral detergent fiber digestibility (H-NDFD)], ‘CDC Copeland’ [intermediate-neutral detergent fiber digestibility (I-NDFD)], and ‘Xena’ [low-neutral detergent fiber digestibility (L-NDFD)] was ranked from 80 commercial silage samples. Cultivars were seeded on the same day, harvested at mid-dough, and ensiled in mini or bunker silos. Mini silos were sequentially opened over 60 d, and day 60 samples were exposed to air for 21 d. Bunker silos were sampled after 60 d. Cultivars did not differ in NDFD, while terminal pH was lower (P < 0.01) for H-NDFD than other silages. The pH of H-NDFD was greater (P < 0.01) and pH of I- and L-NDFD lower (P < 0.01) in bunker than mini silos. Lactate and acetate were greater (P < 0.05) for H-NDFD in mini silos, with lower (P < 0.01) acetate in mini than bunker silos. Intermediate NDFD mini silos were greater (P < 0.01) in acid detergent fiber (ADF) and NDF ...

Registration of ‘Hidden Valley’ Meadow Fescue

‘Hidden Valley’ (Reg. No. CV-100, PI 674472) meadow fescue [Schedonorus pratensis (Huds.) P. Beauv.; syn. Festuca pratensis Huds.; syn. Lolium pratense (Huds.) Darbysh.] is a synthetic population originating from 561 parental genotypes. The original germplasm is of unknown central or northern European origin, but is thought to have become naturalized to the Driftless Area of the Upper Mississippi River Valley over approximately 100 yr. Hidden Valley has forage yield approximately 9% lower than orchardgrass and tall fescue, but neutral detergent fiber digestibility (NDFD) approximately 9% higher than for these two species. Compared to the only other existing meadow fescue cultivar within this region, Hidden Valley has 2% higher forage yield and 1.4% higher NDFD. Hidden Valley is adapted to a wide range of pasture managements and conditions in USDA Hardiness Zones 3 to 5, especially the northern portions of this range.

Replacing conventional with brown midrib corn silage in a total mixed ration: the impact on early and late lactation dairy cow intake, milk yield and composition, and milk fatty acids profile

Brown midrib corn silage (BMRS) is used as an alternative to conventional corn silage (CS) to increase milk yield because of its higher neutral detergent fibre digestibility (NDFD) and DM intake (DMI). Forty Holstein dairy cows were used in a completely randomised design with a 2 × 2 factorial arrangement. Two groups of 13 cows in early lactation (EL) and 7 in late lactation (LL) were fed with a total mixed ration including brown midrib (BMR) or conventional corn silage (C), for a period of 42 days. The cows were milked twice a day, milk yield and DMI were recorded, and NDFD was estimated. Milk composition was measured twice a week and milk fatty acid profile was quantified on the final week of the experiment. In EL, BMR diet increased DMI, NDFD, milk and protein yield whereas milk fat content and yield were decreased. Concentrations of trans-10 C18:1 and trans-10, cis-12 C18:2 in milk were higher in BMR. In LL cows DMI was similar between BMR and C whereas milk and fat yields tended to be higher in C. Fat-corrected milk yield was greater in the C diet. The effect of the BMRS on DMI and milk yield depended on stage of lactation, justifying its use in early lactation. The lower milk fat concentration, observed when BMRS was included in the diets, could be explained in part by an increased concentration of trans-10 C18:1 and trans-10, cis-12 C18:2.

Impact of NDF content and digestibility of diets based on corn silage and alfalfa on intake and milk yield of dairy cows

A meta analysis (22 studies, 83 dietary treatments) evaluated the impact of neutral detergent fiber (NDF) content and whole tract NDF digestibility (NDFD) on dry matter intake (DMI) and milk yield (MY) in high producing dairy cows fed corn silage and alfalfa based diets. Experimental diets were ingested at high levels to support high MY (24.1 and 37.3 kg/d, respectively of DM and MY). The average NDFD was of 42.9% (range: 20.0-68.0 %; within study standard error: ±4.0 %). DMI was negatively related with the dietary NDF (e.g. ± % of NDF caused ±160 g/d of DMI; r 1.0 2=0.51;P<0.01), while NDFD and NDF were positively related (r2=0.74; P<0.01; ±1.0 % of NDF caused approximately ±1.0 % of NDFD). MY was not influenced by dietary NDF. Considering a subset of 5 studies, the regression between NDFD and corn silage:alfalfa ratio in the diet (r2=0.84; P<0.01) allowed to estimate the NDFD of diets containing only alfalfa hay (55%) or corn silage (44%). In conclusion, the dietary NDF concentration influences the NDFD and this has implications both for DMI and MY of cows. Diets based on alfalfa hay have higher NDFD than those based on corn silage.

Effect of varying ruminally degradable to ruminally undegradable protein ratio on nutrient intake, digestibility and N metabolism in Nili Ravi buffalo calves ( Bubalus bubalis)

Four Nili-Ravi buffalo calves (100 ± 4 kg) were used in 4 × 4 Latin Square Design to evaluate the influence of varying ruminally degradable protein (RDP) to ruminally undegradable protein (RUP) ratio on dry matter intake (DMI), digestibility and nitrogen (N) metabolism. Four experimental diets A, B, C and D were formulated to contain RDP:RUP of 70:30, 65:35, 60:40 and 55:45, respectively. The calves were fed ad libitum. Dry matter intake by calves fed C diet was higher ( P < 0.05) than those fed D diet and lower ( P < 0.05) than calves fed A diet, however, it was similar to those fed B diet. There was a linear decrease ( P < 0.01) in DMI with decreasing the RDP to RUP ratio. Similar trend was noticed in crude protein (CP) intake. Neutral detergent fiber (NDF) intake was significantly different across all treatment. The decrease in CP and NDF intake was due to decreasing trend of DMI. Dry matter (DM) digestibility in calves fed A and B diets was higher ( P < 0.05) than those fed C and D diets. A linear decrease ( P < 0.01) in DM digestibility was observed with decreasing the RDP to RUP ratio. Crude protein digestibility remained unaltered across all treatments. Neutral detergent fiber digestibility was higher in calves fed A and B diets than those fed C and D diets. Higher NDF digestibility in calves fed A and B diets was due to higher level of dietary RDP that might resulted in higher ruminal ammonia concentration which stimulate activity of cellulytic bacteria and ultimately increased NDF digestibility. The N retention (g/d) was similar among the calves fed B, C and D diets, however, it was higher ( P < 0.05) than those fed A diet. Decreasing the RDP to RUP ratio resulted in linear increase ( P < 0.01) in N retention. The N retention, as percent of N intake was significantly different across all treatments. Decreasing RDP to RUP ratio resulted in linear increase ( P < 0.01) in N retention, as percent of N intake. A similar trend was noticed in N retention, as percentage of N digestion. Blood urea nitrogen (BUN) concentration in calves fed B diet was higher ( P < 0.05) than those fed D diet and was lower ( P < 0.05) than those fed A diet, however, it was not different from calves fed C diet. Decreasing dietary RDP to RUP ratio resulted in linear decrease ( P < 0.05) in BUN concentrations. The decrease in BUN concentration was because of decreasing level of dietary RDP. The N retention can be increased by decreasing RDP to RUP ratio in the diet of growing buffalo calves and diet containing RDP to RUP ratio 55:45 is considered optimum regarding N retention in buffalo calves.

Effects of Replacing Dietary Starch with Sucrose on Ruminal Fermentation and Nitrogen Metabolism in Continuous Culture

A dual-effluent continuous-culture system was used to evaluate the effects of partially replacing cornstarch with sucrose in a total mixed ration on ruminal fermentation and N metabolism. The 4 treatments were 0 (control), 2.5, 5.0, and 7.5% sucrose and, respectively, 7.5 (control), 5.0, 2.5, and 0% cornstarch in a total mixed ration containing 20% corn silage and 40% alfalfa silage. Fermenters were fed 4 times a day during four 9-d periods with sampling beginning on d 6. Replacing cornstarch with sucrose did not alter ruminal pH (5.97), total volatile fatty acids (VFA) (104.4mmol/L), or the acetate to propionate ratio (2.16); however, branched-chain volatile fatty acids were higher for the control treatment compared with the 7.5% sucrose treatment. Five hours postfeeding, sucrose treatments significantly altered molar proportions of all volatile fatty acids, and acetate-to-propionate and glucogenic-to-lipogenic ratios. Digestibility of dry matter and N were not affected by treatment, but digestibility of total non-structural carbohydrates was increased with sucrose treatments. A quadratic effect was noted for neutral detergent fiber (NDF) digestibility as sucrose replaced starch. A higher NDF digestibility (66.1 vs. 59.9%) was observed for the 7.5% sucrose treatment compared with the other 2 sucrose treatments. Levels of ammonia N were within an acceptable range to support microbial protein synthesis and did not differ among treatments (mean=9.23mg/dL). Sucrose inclusion in the total mixed ration did not affect bacterial N synthesis. Results indicate that (at the levels tested in this study) inclusion of sucrose in the diet when rumen-degradable protein is adequate does not affect ruminal fermentation.

Influence of Brown Midrib, Leafy, and Transgenic Hybrids on Corn Forage Production

Hybrid selection strongly influences corn (Zea mays L.) forage production. Limited forage production and quality information exists for leafy and transgenic hybrids [Bacillus thuringiensis (Bt) and herbicide resistant]. We compared dry matter (DM) yield, forage quality, and estimated milk yields of these and brown midrib hybrids with dual‐purpose hybrids for 3 yr at harvest densities of 66000 and 84000 plants ha−1. Transgenic hybrids had no effect on DM and milk yields, so we do not recommend Bt hybrids under conditions of low infestation of European corn borer (Ostrinia nubilalis Hubner). Leafy hybrids had similar DM and milk yields as hybrids of similar maturity. Brown midrib hybrids, which had DM yields that were about 20% less than those of hybrids of similar maturity, had 40 to 80 g kg−1 greater in vitro true digestibility (IVTD) and 70 to 200 g kg−1 greater neutral detergent fiber (NDF) digestibility. Brown midrib hybrids had the greatest or least milk yields among hybrids, depending on hybrid and year. Leafy and brown midrib hybrids mostly had low harvest index (HI) values, which had strong negative correlations with NDF in all years (−0.71, −0.44, and −0.90). Brown midrib hybrids had high NDF digestibility, which had strong positive correlations with IVTD (0.80, 0.88, and 0.86). Currently, we do not recommend brown midrib hybrids because of inconsistent milk yields and high seed costs. Development of brown midrib and leafy hybrids with greater HI values should result in excellent forage hybrids.

Utilization of browse supplements with varying tannin levels by Ethiopian Menz sheep: 1. Intake, digestibility and live weight changes

The effect of tannins in browse supplements on intake, digestibility and live weight changes was evaluated using sixty-six male Ethiopian Menz sheep in a 90-day trial. Teff straw (Eragrostis tef) was fed ad libitum (control diet), or supplemented with 190 g dried leaves of six Sesbania sesban accessions with increasing levels of condensed tannin (S1, S2, S3, S4, S5 and S6), lablab (Dolichos lablab), tagasaste (Chamaecytisus palmensis), leucaena (Leucaena leucocephala) and goetzei (Sesbania goetzei), in a completely randomized block design. The condensed tannins were highest in goetzei, S6, S5 and leucaena, intermediate in S4, S3, S2 and S1, and lowest in tagasaste and lablab. The forages differed significantly (P S5 > goetzei) in LWG. The digestibilities of total DM and the supplements did not differ significantly (P < 0.05) between the diets, although the neutral detergent fibre (NDF) digestibility decreased significantly (P < 0.05) with supplementation. The control diet had significantly higher NDF digestibility than the leucaena, S3, S4, S5 and S6 supplemented diets. Results have beneficial attributes at low levels in ruminants. Condensed tannins confer important advantages in ruminant nutrition with respect to the prevention of excessive degradation of protein in the rumen.

Enhanced Intake and Production of Cows Offered Ensiled Alfalfa with Higher Neutral Detergent Fiber Digestibility

The objective of this study was to determine the effect of forage fiber digestibility as part of a total mixed diet on intake and production of cows with intakes that were likely limited by rumen fill, using treatments that were not confounded by fiber source, concentrate, or ratio of forage to concentrate. Two alfalfa silages with similar NDF concentrations (40%) but different NDF digestibilities (40 vs. 45% after 24h of in vitro fermentation) were harvested, mixed with concentrate to achieve diets containing 35% NDF, and offered to 12 multiparous cows (13 DIM) in a two-period balanced crossover design. Samples taken during silage feeding revealed that diets differed in both NDF digestibility (3 percentage units) and NDF content (1.8 percentage units), making interpretation of results difficult. Nonetheless, milk production (36.3 vs. 38.2kg/d) and DMI (19.4 vs. 20.4kg/d) were significantly higher with the higher NDF digestibility diet. Apparent in vivo DM and NDF digestibilities, total rumen VFA after feeding, and molar percentage of propionate were also higher with this diet. Equal NDF intake between diets suggested that higher DMI was due to the lower NDF content in the more digestible NDF diet. Higher NDF digestibility might also increase DMI; further experimentation is necessary with larger unconfounded differences in fiber digestibility at the time of feeding.

Effect of dietary starch origin on digestion in the rabbit. 1. Digestibility measurements from weaning to slaughter

Growth performance and digestion in the rabbit could be affected by the source of starch because of gradual changes in intestinal enzymic activity and cecal fermentation. Four starch-rich diets differing mainly in starch origin (purified maize starch (PMS), maize, barley or pea) were compared using groups of ten rabbits between weaning (25 days) and slaughter (75 days). Whole-tract digestibility of major nutrients was assessed at three physiological stages: P1 (28–33 days), P2 (49–54 days) and P3 (70–75 days). Daily feed intake and daily weight gain differed between diets mainly in P1, being respectively: PMS, 29.0 g and 25.8 g; maize, 42.4 g and 36.5 g; barley, 52.4 g and 39.4 g; pea, 50.0 g and 41.0 g. Except in the case of starch, the digestibility of nutrients decreased with age mainly between P1 and P2 (e.g. −9% for organic matter). Fecal losses were detected at weaning for maize (5.4%) and pea (2.2%) diets. Starch from barley and purified maize was completely degraded regardless of the period. Higher neutral detergent fiber digestibility, observed when starch was provided by maize, resulted mainly from a better degradation of the hemicellulosic fraction (53% in P1). High dietary inclusion of peas (60%) was well accepted by rabbits even at weaning.