Ruminal Neutral Detergent Fiber Research Articles

Addition of carbonaceous feedstuffs to broiler litter before deep-stacking

Different types and levels of carbonaceous feedstuffs mixed with broiler litter were incubated in a broiler litter deep-stack for 3 or 9 weeks to determine effects on nutrient composition, recovery and digestibility. Substrates were ground corn (C), whole corn, ground wheat, molasses (M), bermudagrass hay (B), wheat straw and 1:1 (dry matter) mixtures thereof (excluding whole corn and a B-wheat straw mixture) mixed at 10 or 20% of total dry matter with broiler litter. Broiler litter incubated for 3 and 9 weeks had 110 and 106% (SE 1.2) nitrogen recovery, 98 and 118% (SE 1.0) acid detergent fiber nitrogen recovery, 91 and 85% (SE 0.8) neutral detergent fiber recovery, 132 and 148% (SE 4.1) neutral detergent soluble organic matter recovery and 81 and 75% (SE 1.1) in situ ruminal (48 h) neutral detergent fiber disappearance, respectively. In general, effects of C, whole corn and wheat were similar, as well as were those of B and wheat straw. Nitrogen recovery was increased by singular addition of M; associative effects of mixing M with other carbonaceous feedstuffs occurred; and M effects varied with level of addition and length of incubation (112, 131, 114, 124 and 123% with 10% substrate, and 114, 146, 116, 134 and 135% with 20% substrate (SE 1.50); 113, 133, 114, 124 and 127% with 3-week incubation, and 113, 144, 116, 134 and 131% with 9-week incubation (SE 1.50) for C, M, B, C-M and M-B, respectively). Recovery of acid detergent fiber N was increased by cereal grain inclusion (112, 100, 96, 111 and 107% with 10% substrate, and 125, 106, 84, 110 and 91% with 20% substrate (SE 3.4); 114, 103, 81, 113 and 105 with 3-week incubation, and 123, 103, 100, 109 and 93% with 9-week incubation (SE 3.42) for C, M, B, C-M and M-B, respectively). Molasses inclusion decreased neutral detergent fiber recovery more at 20 than 10% and at 9 vs 3 weeks of incubation (106, 76, 84, 81 and 75% with 10% substrate, and 111, 68, 86, 75 and 70% with 20% substrate; 107, 82, 88, 82 and 80% with 3-week incubation, and 110, 63, 83, 74 and 65% with 9-week incubation (SE 2.13) for C, M, B, C-M and M-B, respectively). Recovery of neutral detergent soluble organic matter generally varied inversely with neutral detergent fiber recovery. Molasses resulted in 48-h in situ ruminal neutral detergent fiber disappearance, greater than expected based on the disappearance of feedstuffs before deep-stacking (3-week incubation: 4, 15, 1, −1 and 4% difference (SE 0.88); 9-week incubation: −12, 3, −13, 1 and 0% difference with 10% substrate, and −10, 9, −11, 0 and 0% difference with 20% substrate (SE 1.21) for C, M, B, C-M and M-B, respectively). In conclusion, molasses addition resulted in a number of changes, suggesting improved nutritive value of broiler litter.

Prediction of the nutritive value of lucerne hay in diets for growing rabbits

Fifty-one New Zealand White × California rabbits were used to evaluate apparent in vivo dry matter (DM), organic matter (OM), energy, nitrogen (N), neutral detergent fibre (NDF) and amino acid digestibilities of five lucerne hays varying in chemical composition. Hays were ground and pelleted and given as sole feeds throughout the experiment. In vitro DM, OM, NDF and N digestibilities of feed samples were also determined. A ruminal incubation trial was performed to determine NDF disappearance of lucerne hays in nylon bags. The type of lucerne hay had a large effect on its nutritive value. The range of variation for digestible energy (DE) and digestible crude protein (CP) contents and for NDF digestibility was 6.4–9.2 kJ g −1, 114–164 g kg −1 and 0.204–0.276, respectively. The type of lucerne hay also affected lysine, methionine and threonine digestibilities. Stepwise regression analysis showed that the best single predictors for energy, CP, NDF and amino acid digestibilities were dietary NDF and non starch polysaccharide (NSP) contents, ruminal NDF degradability after 48 h of incubation and CP digestibility, respectively. Regressions using only chemical components as independent variables were also calculated. The results of this study showed that in vitro methods and prediction equations determined for mixed diets and concentrated ingredients need to be adjusted to estimate nutritive value of forages in rabbits.

Ruminal plant cell wall digestibility estimated from digestion and passage kinetics utilizing mathematical models

Methods to describe the digestion and passage kinetics for estimating ruminal neutral detergent fibre digestibility (RNDFD) with simple mathematical models were evaluated in cattle fed a diet of hay, barley and urea (600, 396 and 4 g dry matter (DM) kg −1 total DM) at two levels of intake. The parameters of digestion kinetics were determined by in situ incubation and rumen evacuation technique. Digesta passage kinetics was estimated from duodenal and faecal Cr and Yb concentrations either from exponential decline in marker concentration or by using two-compartmental models with gamma age dependency in the first compartment. Increasing the feeding level from 40 to 80 g DM kg −1 live weight 0.75 decreased ( P < 0.05) the digestibility of DM (0.775 vs. 0.749), DNF (0.758 vs. 0.707) and cell solubles (0.838 vs. 0.824). The amount of total digesta, digesta DM content and the amount of DM in the rumen increased as feed intake increased. The relative increase in rumen pool size of digestible NDF was greater than in that of indigestible NDF (0.72 vs. 0.34). Using in situ digestion kinetics data and the exponential decline in marker concentration in a simple rumen digestion model yielded RNDFD estimates which were much lower than those based on rumen evacuation data, and only about 0.70 of the total in vivo NDF digestibility. This was partly because of the slower ( P < 0.01) rate of digestion observed with the in situ method than estimated from rumen evacuation (0.0458 vs. 0.0607), and partly because of an underestimation of rumen residence time by the passage model. Incorporation of the selective retention of feed particles in the digestion model yielded RNDFD estimates which were 0.13 units higher than those based on exponential marker concentration decline curves. The kinetics parameters for this model were calculated from duodenal marker concentrations using two-compartmental passage models. The RNDFD estimates were 0.94–0.96 of the total in vivo NDF digestibility when the passage kinetics parameters, estimated with the two-compartmental model, were used in combination with the rumen evacuation derived rate of digestion. The values for RNDFD were higher when Cr and faecal sampling were used rather than Yb and duodenal sampling to estimate passage kinetics.

Influence of Ruminally Dispensed Monensin and Forage Maturity on Intake and Digestion

Eight ruminally cannulated crossbred steers (average weight 336 kg) grazing native blue grama (Bouteloua gracilis [H.B.K.]) rangeland were used in a repeated measures design to evaluate effects of monensin ruminal delivery devices (MRDD) and forage phenology on ruminal digestion. Three periods were assessed: mid-August (Aug.), early October (Oct.), and mid-November (Nov.). One MRDD was placed in the reticulum of 4 steers via the ruminal cannula 21 days before each period. Intake was estimated using total fecal collections. Diet samples were collected using 3 esophageally fistulated steers. Ruminal fill was measured by ruminal evacuation; rate and extent of in situ ruminal neutral detergent fiber disappearance were estimated before ruminal evacuations. Ruminal passage rates, retention time, and apparent total tract organic matter digestibility were estimated using indigestible neutral detergent fiber. In vitro organic matter disappearance of esophageal masticate did not differ (P > .05) in Aug. and Oct. (average of 53.7%), but declined (P .10) by MRDD. In situ neutral detergent fiber disappearance at 96 hours was decreased (P < .10) by MRDD (68 vs 65% for control and MRDD, respectively). As the grazing season progressed, intake declined (P < .10), whereas ruminal fill and retention time increased (P < .05), and passage rate of indigestible neutral detergent fiber decreased (P < .05). At 48 hours in situ neutral detergent fiber was greatest (P < .05) in Aug. and least (P < .05) in Nov.

Digestion properties of ammoniated rice straw in the rumen and lower tract of sheep

The effect of ammoniation of rice straw (2 g NH 3 per 100 g dry matter (DM)) on digestibilities and fermentation in the rumen and lower tract of sheep was investigated. Four sheep fitted with cannulae in the rumen and the duodenum were used in a 4 × 4 Latin square experiment. Diets were formulated to contain 80% rice straw and 20% supplement. These were an ammoniated rice straw diet (80% ammoniated rice straw +20% formula feed), a urea-supplemented diet (80% untreated rice straw +18.9% formula feed +1.1% urea), a soya-bean meal diet (80% untreated rice straw +11.1% formula feed +8.9% soya-bean meal) and a control diet (80% untreated rice straw +20% formula feed). There was a significant increase ( P < 0.05) in apparent rumen organic matter (OM) digestibility in sheep on the ammoniated rice straw diet. Apparent total tract DM and OM digestibilities were increased ( P < 0.05) in ammoniated rice straw-fed animals. The digestibility was 11% greater than that of the control. Apparent ruminal neutral detergent fibre (NDF) digestibilities were enhanced ( P < 0.05) in animals on the ammoniated rice straw diet and the diet supplemented with soyabean meal. However, digestibility of the ammoniated rice straw diet was 13% greater than that of the diet supplemented with soya-bean meal. Total tract NDF digestibility in the ammoniated diet was 17% greater than that of the control. At all sampling periods, the total volatile fatty acid (VFA) was highest and pH lowest in animals on the ammoniated diet. Ruminal n-butyrate proportion was increased ( P < 0.05) in sheep fed the ammoniated diet at 0 h. Total VFA and acetate proportion in rectal samples of animals fed the ammoniated rice straw diet were significantly lower ( P < 0.05). However, n-butyrate and n-valerate proportions were increased ( P < 0.05). Gram-negative cocci and gram-negative rods appeared to be the predominant bacteria in sheep on rice straw diets. There was a significantly higher ( P < 0.05) rectal total bacterial count in sheep on the ammoniated diet. Ruminal cellulolytic bacterial count tended to increase in animals fed the ammoniated diet. Neither bacterial flow at the duodenum nor nitrogen retention differed significantly among treatments.

Intake and digestion in cattle fed warm- or cool-season grass hay with or without supplemental grain.

Intake and digestion in cattle fed warm- or cool-season grass hay with or without low-level grain supplementation were studied with a 2 x 2 factorial arrangement of treatments in two 4 x 4 Latin square experiments. In Exp. 1, four cannulated beef cows (396 kg) were given Bermuda grass (B) or orchard grass (OG) hay at 1.5% body weight (BW) with 0 or .3% BW of ground corn (C; dry matter). Bermuda grass contained 12.1% crude protein, 79.3% neutral detergent fiber (NDF) and 5.5% acid detergent lignin (ADL); OG contained 10.6% crude protein, 82.4% NDF and 8.1% ADL. An interaction (P less than .07) between forage type and C supplementation was noted for microbial N entering the duodenum; C supplementation had a positive effect with B (30% increase) and little effect with OG. Corn supplementation did not affect ruminal NDF digestion with B, but it elicited an increase with OG (interaction, P less than .05; means were 60.7, 60.1, 61.5 and 66.3%). In the second experiment, growing dairy steers (196 kg) were given ad libitum access to similar B or OG hays and were fed 0 or .5% BW of C. Dry matter (DM) intake was lower for OG than for B (P less than .05) and was lower with than without C (P less than .06; means were 2.76, 2.56, 2.53 and 2.30% BW for B, BC, OG and OGC, respectively). Total tract organic matter digestion (%) was higher for OG than for B (P less than .10) and was higher with than without C (means were 54.7, 61.5, 60.4 and 65.3%). In conclusion, chemical constituents such as NDF may govern differences in intake between warm- and cool-season grasses, but physical attributes of the forages appear more important to digestion.

Effects of dietary forage proportion on digestive function in maintenance-fed beef cows. 1. Fescue and clover hays.

Five crossbred beef cows (Hereford X Angus, 422 kg) with ruminal and duodenal cannulae were used in a Latin square experiment to determine the effects of dietary proportions of fescue and clover hays (0:1, .25: .75, .5:.5, .75:.25 and 1:0) on digestive function. Feed intake was 85% of ad libitum intake of fescue alone (1.03% of body weight). Fescue contained 1.26% nitrogen (N), 71.0% neutral detergent fibre (NDF) and 7.6% acid detergent lignin (ADL), and clover contained 2.43% N 50.0% NDF and 5.8% ADL in DM. Ruminal fluid ammonia-N concentration increased linearly (P less than .05) with declining dietary fescue level. Total concentration of volatile fatty acids in ruminal fluid and duodenal and rectal digesta mean particle size were not affected by fescue level. Ruminal fluid volume and flow rate increased linearly (P less than .05) with increasing dietary fescue, but fluid and particulate digesta passage rates were unchanged. Apparent ruminal organic matter (OM) digestion decreased quadratically (P less than .05) as fescue increased (74.5, 54.3, 49.8, 46.2 and 42.4% for 0, 25, 50, 75 and 100% fescue, respectively). Postruminal OM digestion as a percentage of intake was partially compensatory, increasing linearly (P less than .05) as dietary fescue level rose (2.3, 3.5, 5.1, 8.6 and 11.1% of intake). Thus, total tract OM digestion declined less as fescue replaced clover (76.8, 57.8, 55.0, 54.8 and 53.5%; linear and quadratic, P less than .05) than did apparent ruminal OM disappearance. Changes in ruminal NDF, acid detergent fibre and cellulose digestibilities were similar to those for OM. Microbial growth efficiency increased quadratically (P less than .10) as fescue intake increased. These results indicate that with low feed intake, ruminal and total tract digestion of an all-legume hay diet is greater than that of a grass hay diet. Little or no digestive advantage was achieved by substituting clover for fescue, except in the case of total replacement of fescue with clover, because of concurrent decreases in microbial growth efficiency, microbial N flow to the intestines and OM digestion in the postruminal tract. Negative associative effects in digestion observed between clover and fescue hays in this experiment deserve further study.

Monensin effects on digestibility, ruminal protein escape and microbial protein synthesis on high-fiber diets.

The influence of monensin level (0, 6.1, 12.2, 18.3 and 36.6 ppm) on diet fiber digestibility, microbial protein synthesis and ruminal escape of dietary protein was evaluated in two steer metabolism trials. A growth trial was conducted to study possible interactions of forage quality and monensin level. In metabolism trial 1, four ruminal-cannulated steers were assigned to four monensin levels in a 4 X 4 Latin square design to measure fiber digestibility, rate of passage and protein metabolism. In metabolism trial 2, five duodenal-cannulated steers were assigned to five monensin levels in a 5 X 5 Latin square design to measure fiber digestibility, bacterial N flow and plant N flow. In the two metabolism trials, the level of monensin influenced organic matter (OM) digestibility, neutral detergent fiber (NDF) digestibility and ruminal NDF digestibility quadratically, with the intermediate levels of monensin being superior either to the high level of monensin or no monensin. A quadratic increase in particulate disappearance rate (P = .09) and no effect (P = .95) on liquid disappearance were also observed in trial 1. In trial 1, monensin level quadratically decreased (P = .10) the bacterial protein concentration and increased (P = .02) the ratio of total N:diaminopimilic acid in whole rumen contents. In trial 2, no overall difference in duodenal N flow (P = .64) or flow of individual amino acids (P = .46) was observed. In the growth trial, no interaction of cornstalk quality and monensin was observed (P less than .38).(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of limestone level in high concentrate and high roughage diets on site and extent of digestion in lambs.

Two digestion and slaughter trials were conducted to evaluate the influence of limestone level on site and extent of digestion and rumen fermentation in lambs. In trial 1, 11 wether lambs (avg wt 40.7 kg) were fed 75% concentrate diets supplemented with .6, 1.5 or 3.0% limestone (.6,1.2,1.7% dietary Ca, respectively) in a completely randomized design. Dry matter intake increased linearly (P less than .10) with limestone level; therefore, other data were analyzed with dry matter intake as a covariate. Total tract organic matter digestion decreased linearly (P less than .05) with increasing limestone but dry matter and fiber digestion were not affected by limestone. Ruminal digestion of dry matter and organic matter declined linearly (P less than .05) with increasing limestone. Ruminal neutral detergent fiber (NDF) digestion was higher with the 1.5 than the .6 and 3.0% limestone diets (quadratic effect, P less than .05) but ruminal digestion of other fiber components was not affected by limestone. Ruminal volatile fatty acids were not affected by limestone level; however, rumen ammonia concentrations decreased linearly (P less than .05) with increasing limestone level. In trial 2, 12 wether lambs (avg wt 43.3 kg) were fed a 35% concentrate diet with .1, 1.5 or 3.0% limestone (.5, 1.2 and 1.6% dietary Ca, respectively) in a completely randomized design. Dry matter intake was not affected by limestone level, but digestibility of dry matter, organic matter and starch (P less than .10), energy, crude protein, acid detergent fiber (ADF) and cellulose (P less than .05) responded quadratically to limestone level, with increases at the 1.5% limestone level. Ruminal dry and organic matter (P less than .05), NDF (P less than .10), ADF (P less than .01), cellulose (P less than .05) and starch (P less than .05) digestion responded quadratically to limestone level with higher values at the 1.5% limestone level. Proportions of ruminal propionate increased linearly (P less than .01) with increasing limestone level and acetate: propionate ratio declined linearly (P less than .01) with limestone level.

Effect of Low and High Fill Diets on Dry Matter Intake, Milk Production, and Reproductive Performance During Early Lactation

Feedstuffs analyzed for rate and extent of ruminal neutral detergent fiber disappearance were used to formulate two diets that differed for predicted time required for ruminal clearance of neutral detergent fiber. Diets with slow and fast estimated disappearance rate of neutral detergent fiber were termed and high and low fill, respectively. For both diets, crude protein, acid detergent fiber, neutral detergent fiber, net energy of lactation, and soluble protein were similar. Twenty-eight lactating cows were limit fed the rations 2 wk prior to calving, then fed for ad libitum consumption until 8 wk after calving.Cows fed low fill produced more milk (30.3 vs. 26.3kg) and milk protein (.97 vs. .78kg) and had higher incidence of short estrous cycles and fewer acyclic cows by 8 wk postpartum than cows offered high fill. Dry matter intake, fat-corrected milk yield, daily fat production, and solids-not-fat did not differ between diets. Rumen fermentation measurements for pH and ammonia-nitrogen concentrations were also not different between diets. Cows fed low fill tended to have higher rates of solids and liquid turnover and lower total dry matter in the rumen compared with cows fed high fill. Low ruminal pH on both diets as well as other physiological mechanisms may have been responsible for failure of rates of nuetral detergent fiber disappearance to affect intake of dry matter.

Rate and Extent of Neutral Detergent Fiber Degradation of Feedstuffs in Situ

Rate and extent of neutral detergent fiber degradation were determined for 22 feedstuffs in situ. Polyester bags containing 8g of a forage or 5g of a grain were suspended in the rumen of cannulated dairy animals .5h after feeding and were removed at intervals up to 48h. Major differences were among feeds in both extent and rate of neutral detergent fiber degradation; however, positive relationship between these two measures of digestion was not close. Lag times were associated with variability of digestion of the neutral detergent fiber fraction of forages as well as of some grains.Neutral detergent fiber fill, representing the ratio of ruminal neutral detergent fiber to neutral detergent fiber turnover rate, was calculated for each feed from its turnover rate constant, lag time, potential digestibility in situ, and rate of passage. Two diets then were formulated to be similar in chemical composition but to differ in fill. When these diets were tested in situ, the rate and extent of neutral detergent fiber degraded at 24h was .024h−1 and 43% versus .074h−1 and 58% for the high and low fill diets. It is possible to utilize variability among feeds of rate and extent of neutral detergent fiber degradation to formulate diets that may promote greater intake.