Monitoring digestibility of forages for herbivores: a new application for an old approach

2015 ◽  
Vol 93 (3) ◽  
pp. 187-195 ◽  
Author(s):  
L.L. VanSomeren ◽  
P.S. Barboza ◽  
D.P. Thompson ◽  
D.D. Gustine

Ruminant populations are often limited by how well individuals are able to acquire nutrients for growth, maintenance, and reproduction. Nutrient supply to the animal is dictated by the concentration of nutrients in feeds and the efficiency of digesting those nutrients (i.e., digestibility). Many different methods have been used to measure digestibility of forages for wild herbivores, all of which rely on collecting rumen fluid from animals or incubation within animals. Animal-based methods can provide useful estimates, but the approach is limited by the expense of fistulated animals, wide variation in digestibility among animals, and contamination from endogenous and microbial sources that impairs the estimation of nutrient digestibility. We tested an in vitro method using a two-stage procedure using purified enzymes. The first stage, a 6 h acid–pepsin treatment, was followed by a combined 72 h amylase–cellulase or amylase–Viscozyme treatment. We then validated our estimates using in sacco and in vivo methods to digest samples of the same forages. In vitro estimates of dry matter (DM) digestibility were correlated with estimates of in sacco and in vivo DM digestibility (both P < 0.01). The in vitro procedure using Viscozyme (r2 = 0.77) was more precise than the in vitro procedure using cellulase (r2 = 0.59). Both procedures can be used to predict in sacco digestibility after correcting for the biases of each method. We used the in vitro method to measure digestibility of nitrogen (N; 0.07–0.95 g/g), which declined to zero as total N content declined below 0.03–0.06 g/g of DM. The in vitro method is well suited to monitoring forage quality over multiple years because it is reproducible, can be used with minimal investment by other laboratories without animal facilities, and can measure digestibility of individual nutrients such as N.

1996 ◽  
Vol 126 (2) ◽  
pp. 235-248 ◽  
Author(s):  
I. V. Nsahlai ◽  
N. N. Umunna

SUMMARYThis study (conducted in Debre Zeit, Ethiopia in 1993) examined (i) the effect of source of inoculum on in vitro dry matter (DM) digestibility (1VDMD) and gas production (GP) and (ii) the IVDMD, GP and in sacco degradability as predictors of in vivo DM digestibility (DMD) and intake. Six ruminally cannulated male sheep (used in the degradability studies and from which rumen fluid was harvested for the in vitro studies) and six intact sheep (from which faeces for reconstitution was obtained) were given teff straw ad libitum supplemented with 200 g/day of concentrate (1:1 mixture of noug (Guizotia abyssinica) cake and wheat middlings). In determining IVDMD on 26 feeds, pepsin-HC1 digestion was replaced with neutral detergent extraction. Microbial GP was measured on these feeds incubated with rumen fluid or reconstituted faeces inocula at various time periods. The degradability of each feed was determined by the nylon bag technique in three sheep. Eighty-eight intact male Ethiopian Menz type sheep (mean liveweight 256 (S.D. = 1·98) kg) were used in a randomized complete block experiment to determine intake and digestibility.Gas production using faeces inoculum (GP-F) was strongly related to GP using rumen fluid inoculum (GP-R) particularly at 48 h (R2 = 0·85; P <0·001) of incubation. The IVDMD obtained with reconstituted sheep faeces inoculum (IVDMD-F) had a strong positive relationship (R2 = 0·88; P <0·0001) with IVDMD measured using rumen fluid (IVDMD-R). The IVDMD values obtained by centrifugation were positively related to those obtained by filtration for the rumen fluid (R2 = 0·61) and reconstituted faeces (R2 = 0·47) inocula.The relationship between degradability and in vivo DMD was generally poor for roughages but improved with the length of incubation for forage legumes, being strongest at 24 h (R2 = 0·54). The in vivo DMD had the strongest relationship with GP-R at 24 h of incubation for roughages (R2 = 0·64) and legumes (R2 = 0·84). Dry matter degradability was poorly related to DM intake for roughages (R2 <0·10), while these were closely related for legumes particularly at 6 h of incubation (R2 = 0·55). The relationship between GP-R and intake was strongest at 12 h of incubation for roughages (R2 = 0·41) but was generally weak for legumes. The IVDMD accounted for a very low proportion of the variation in intake of roughages and legume forages. The gas production method was the best among the methods tested in predicting voluntary roughage intake, but not the intake of legumes. The nylon bag technique gave the best predictors (solubility, rate constant ‘c’ and Lag phase) of legume intake (R2 = 0·98).The discussion suggests explanations for why the nylon bag technique predicted performance from forage legumes better than from roughages, why the technique was much better as a predictor of intake than of in vivo DMD, and why the gas production technique predicted in vivo DMD and not the intake of legumes. Reconstituted faeces inoculum may replace rumen fluid inoculum in in vitro procedures. The IVDMD method is a less accurate predictor of in vivo DMD than GP and rumen degradability constants. Both feed factors and practices inherent in the methodologies may modify the predictiveness of indirect digestibility methods.


2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 55-56
Author(s):  
Noheli Gutierrez ◽  
Jamie A Boyd

Abstract A study was conducted to evaluate effects of increasing concentration of food grade glycerol on rumen environment and nutrient digestibility. Three ruminally cannulated Jersey steers were used in this study. The study was conducted from March to May 2019. Experimental design was a 3x3 Latin square with a 2wk adjustment period followed by a 1wk collection period. Diet was coastal bermudagrass hay based. Different forage types were introduced in the incubation process to evaluate digestibility. Glycerol was administered once a day at 0, 15, or 20% of DMI (dry matter intake). dNDF (digestible NDF) and dDM (digestible dry matter) was determined using an ANKOM Daisy II incubator inoculated with 200g fresh rumen fluid and incubated for 12, 24, 48 and 72 h at 39°C. Each vessel contained ground forage samples in filter bags in triplicate. After incubation, filter bags were rinsed with cold water and dried for 24h in a 55°C forced air oven. Data were analyzed using the Proc MIXED procedure of SAS version 9.4. There was no difference dNDF in effect of different levels of glycerol between forage types by diet. But a numerical tendency was observed that dNDF was decreased at 20% inclusion rates in comparison to 0 and 15% inclusion of glycerol in the diet. Neither steer nor run was significantly different in the study. However as expected digestibility over time was significantly different (P &lt; 0.001). A significant increase was observed in DMI with the increased levels of glycerol in the diet (P = 0.003), both the 15% and 20% levels of glycerol increased in DMI in comparison to the control (0%). It appears based on these study results that digestibility may be inhibited, as levels of dietary glycerol increase in the diet and more work needs to be done to find the optimal level of glycerol supplementation.


1995 ◽  
Vol 1995 ◽  
pp. 113-113
Author(s):  
D M Harris ◽  
A Barlet ◽  
A T Chamberlain

The pressure transducer technique has been proposed as a method of evaluating feed degradation characteristics (Theodorou, 1993) and it has been shown to predict the in vivo and in sacco degradability of forages (Blummel and Orskov, 1993). However the original technique requires rumen liquor and hence access to surgically prepared animals. Faecal material is generally easier to obtain and this work assessed it's suitability as an alternative source of microbes.Rumen liquor (R) and faeces (F) were collected simultaneously from a rumenally fistulated lactating dairy cow. R was mixed 1:1 with modified van Soest medium and F 1:2 to obtain similar dry matter contents. Homogenised strained 20 ml aliquats were inoculated into vented 250 ml bottles containing 180 ml of modified van Soest medium and 1.5g DM of a 7:3 mixture of milled air dried grass silage and 180 g CP / kg DM concentrates. The 7:3 ratio of silage and concentrates was chosen to reflect the diet the donor cow was consuming.


2009 ◽  
Vol 49 (7) ◽  
pp. 563 ◽  
Author(s):  
David B. Coates ◽  
Robert J. Mayer

In a study that included C4 tropical grasses, C3 temperate grasses and C3 pasture legumes, in vitro dry matter digestibility of extrusa, measured as in vitro dry matter loss (IVDML) during incubation, compared with that of the forage consumed, was greater for grass extrusa but not for legume extrusa. The increase in digestibility was not caused by mastication or by the freezing of extrusa samples during storage but by the action of saliva. Comparable increases in IVDML were achieved merely by mixing bovine saliva with ground forage samples. Differences were greater than could be explained by increases due to completely digestible salivary DM. There was no significant difference between animals in relation to the saliva effect on IVDML and, except for some minor differences, similar saliva effects on IVDML were measured using either the pepsin–cellulase or rumen fluid–pepsin in vitro techniques. For both C4 and C3 grasses the magnitude of the differences were inversely related to IVDML of the feed and there was little or no difference between extrusa and feed at high digestibilities (>70%) whereas differences of more than 10 percentage units were measured on low quality grass forages. The data did not suggest that the extrusa or saliva effect on digestibility was different for C3 grasses than for C4 grasses but data on C3 grasses were limited to few species and to high digestibility samples. For legume forages there was no saliva effect when the pepsin–cellulase method was used but there was a small but significant positive effect using the rumen fluid–pepsin method. It was concluded that when samples of extrusa are analysed using in vitro techniques, predicted in vivo digestibility of the feed consumed will often be overestimated, especially for low quality grass diets. The implications of overestimating in vivo digestibility and suggestions for overcoming such errors are discussed.


1999 ◽  
Vol 1999 ◽  
pp. 151-151 ◽  
Author(s):  
I.C.S. Bueno ◽  
A.L. Abdalla ◽  
S.L.S. Cabral Filho ◽  
D.M.S.S. Vitti ◽  
E. Owen ◽  
...  

The use of small ruminants, such as sheep, in metabolism studies is more convenient as handling problems are reduced and their maintenance costs are lower, in comparison with cattle. However in vivo digestibility estimates obtained at maintenance are known to differ between these two species. With the increased use ofin vitrogas production techniques, to evaluate ruminant feedingstuffs, it is of great importance to identify whether the species from which the rumen fluid inoculum is obtained has a significant influence on the results obtained.Rumen fluid samples were obtained from a non-lactating Holstein cow (C) and six wether sheep (S) offered the same diet (80 % tropical grass and 20 % dairy concentrate) and prepared so as to have similar dry matter (DM) contents and therefore potentially the microbial mass. Nine substrates (two tropical grasses 1-2, tropical alfalfa 3, barley straw 4, and five temperate grasses 5-9) were examined.


1995 ◽  
Vol 1995 ◽  
pp. 113-113 ◽  
Author(s):  
D M Harris ◽  
A Barlet ◽  
A T Chamberlain

The pressure transducer technique has been proposed as a method of evaluating feed degradation characteristics (Theodorou, 1993) and it has been shown to predict the in vivo and in sacco degradability of forages (Blummel and Orskov, 1993). However the original technique requires rumen liquor and hence access to surgically prepared animals. Faecal material is generally easier to obtain and this work assessed it's suitability as an alternative source of microbes.Rumen liquor (R) and faeces (F) were collected simultaneously from a rumenally fistulated lactating dairy cow. R was mixed 1:1 with modified van Soest medium and F 1:2 to obtain similar dry matter contents. Homogenised strained 20 ml aliquats were inoculated into vented 250 ml bottles containing 180 ml of modified van Soest medium and 1.5g DM of a 7:3 mixture of milled air dried grass silage and 180 g CP / kg DM concentrates. The 7:3 ratio of silage and concentrates was chosen to reflect the diet the donor cow was consuming.


2017 ◽  
Vol 48 (2) ◽  
pp. 63-69
Author(s):  
M. Joch ◽  
V. Kudrna ◽  
B. Hučko

AbstractThe objective of this study was to determine the effects of geraniol and camphene at three dosages (300, 600, and 900 mg l-1) on rumen microbial fermentation and methane emission in in vitro batch culture of rumen fluid supplied with a 60 : 40 forage : concentrate substrate (16.2% crude protein, 33.1% neutral detergent fibre). The ionophore antibiotic monensin (8 mg/l) was used as positive control. Compared to control, geraniol significantly (P < 0.05) reduced methane production with increasing doses, with reductions by 10.2, 66.9, and 97.9%. However, total volatile fatty acids (VFA) production and in vitro dry matter digestibility were also reduced (P < 0.05) by all doses of geraniol. Camphene demonstrated weak and unpromising effects on rumen fermentation. Camphene did not decrease (P > 0.05) methane production and slightly decreased (P < 0.05) VFA production. Due to the strong antimethanogenic effect of geraniol a careful selection of dose and combination with other antimethanogenic compounds may be effective in mitigating methane emission from ruminants. However, if a reduction in total VFA production and dry matter digestibility persisted in vivo, geraniol would have a negative effect on animal productivity.


1985 ◽  
Vol 53 (3) ◽  
pp. 691-708 ◽  
Author(s):  
J. A. Rooke ◽  
H. A. Greife ◽  
D. G. Armstrong

1. In a 4 × 4 Latin square experiment four cattle were given in two meals per d diets consisting of (g/kg dry matter (DM)) 500 barley, 400 grass silage and 100 soya-bean meal. The diets were given at either 1.15 (L) or 2.3 times (H) maintenance energy requirements and the soya-bean meal was either untreated (U) or formaldehydetreated (T).2. A 24 h collection of duodenal digesta and a 7 d collection of faeces were made using chromium sesquioxide for flow estimation and 35S as a marker of microbial nitrogen entering the small intestine. Samples of rumen fluid were also taken for estimation of lumen pH, ammonia and volatile fatty acid concentrations.3. Spot samples of duodenal digesta were obtained after administration of Cr2O3,-mordanted silage-fibre and soya-bean meal, to determine the rates of outflow of these markers from the rumen. Similar samples were also obtained after cessation of a continuous intraruminal infusion of ruthenium phenanthroline, 35S and CoEDTA.4. Incubations of each feedingstuff in porous synthetic fibre (psf) bags were carried out in the rumen and the rates of N disappearance from the bags determined.5. Increasing DM intake significantly ( P < 0.001) increased the quantities of organic matter (OM), total N and amino acid-N entering the small intestine and amounts subsequently voided in the faeces. Apparent digestibilities of OM and N were unaffected by DM intake; the proportions of total digestible OM digested in the rumen were significantly lower (P < 0.01) at the higher level of DM intake.6. Formaldehyde treatment of the soya-bean meal increased the quantities of N entering the small intestine; these increases were not significant.7. Increased DM intake increased the quantities of both microbial N (P < 0.001) and undegraded feed N (P < 0.01) entering the small intestine; HCHO-treatment also significantly (P < 0.05) increased the quantities of undegraded feed N entering the small intestine. The efficiency of microbial N synthesis within the lumen was not significantly affected by dietary treatments whereas apparent feed N degradability was reduced significantly ( P < 0.05) both by increasing DM intake and by HCHO-treatment of the soya-bean meal.8. Rates of disappearance of N from psf bags in the rumen were different for different feedingstuffs. However, for a given feedingstuff, the rate of N disappearance was not affected by the diets fed.9. The rates of decline in marker concentrations measured in duodenal digesta were significantly increased as DM intake increased with the exception of Cr2O2-soya-bean meal. The markers could be ranked (P < 0.05) in the following order of increasing outflow rate: ruthenium phenanthroline, 35S-labelled amino acids and Cr2O2-silage fibre < Cr2O3-soya-bean meal < CoEDTA.10. Estimates of the degradabilities of feedingstuffs were calculated from N disappearance rates from psf bags and either experimentally determined outflow rates or those proposed by the Agricultural Research Council (1984). Such estimates for the degradability of the whole diet were then compared with those determined in vivo using 35S as a marker.


1980 ◽  
Vol 43 (2) ◽  
pp. 389-391 ◽  
Author(s):  
K. Sakamoto ◽  
T. Asano ◽  
S. Furuya ◽  
S. Takahashi

1. Dry matter and crude protein (nitrogen × 6.25) digestibility of four poultry diets determined by an in vitro method using the intestinal fluid of pigs was significantly correlated with corresponding in vivo digestibility values obtained with hens.2. The intestinal fluid could be lyophilized and stored for at least 35 d without losing its activity on digestion.


1983 ◽  
Vol 50 (3) ◽  
pp. 555-568 ◽  
Author(s):  
U. Krishnamoorthy ◽  
C. J. Sniffen ◽  
M. D. Stern ◽  
P. J. Van Soest

1. Twelve grain mixtures, one lucerne (Medicago sativa) hay and one maize silage which had been used in mixed diets for which dietary nitrogen undegraded in the rumen (UDN) had been estimated with duodenally-cannulated cows, were studied. Total N in the feeds was fractionated into pool A (N soluble in borate–phosphate buffer), pool B (total N–(pool A + pool C)) and pool C (acid-detergent-insoluble N or residual N after 24 h incubation in protease solution).2. N solubilization in protease solution containing 6·6 units/ml (substrate-saturating enzyme concentration) indicated the presence of subfractions in pool B, with different rates of solubilization. Such subfractions were not detectable from in situ, Dacron bag, estimates of N solubilization.3. UDN was estimated using a dynamic mathematical model and rate-constants obtained from N solubilization in protease solution or in situ.For three grain mixtures tested using the protease technique the model predicted UDN values of 7, 10 and 12% compared with values of 47, 66 and 59% estimated in vivo. The full range of experimental feeds was tested using the in situtechnique and UDN values predicted by the model were used to derive UDN values for twelve mixed diets. The latter values were significantly but not closely correlated with those determined in vivo (r2 0·41, P < 0·05).4. An attempt was made to simulate rumen proteolysis in vitro by choosing a protease enzyme concentration (0·066 units/ml) providing a proteolytic activity similar to that of whole rumen fluid. The experimental samples of feed were subjected to simulated rumen proteolysis for 18 or 48 h to resemble the mean retention times in the rumen for grain mixtures and roughages respectively. The residual N at the end of incubation was considered as an estimate of UDN. The UDN values estimated from simulated rumen proteolysis and those determined in vivo for twelve mixed diets were in close agreement (r2 0·61, P < 0·01).5. Simulated rumen proteolysis can serve as a simple, rapid and sensitive method to estimate UDN in a variety of feedstuffs.


Sign in / Sign up

Export Citation Format

Share Document