In Vivo Nylon Bag vs. Two‐Stage In Vitro Digestion: Comparison of Two Techniques for Estimating Dry‐Matter Digestibility of Forages 1

1969 ◽  
Vol 61 (4) ◽  
pp. 587-589 ◽  
Author(s):  
W. G. Manson ◽  
R. S. Lowrey ◽  
Ian Forbes
1971 ◽  
Vol 22 (5) ◽  
pp. 787 ◽  
Author(s):  
GD Brown ◽  
JC Radcliffe

Twenty experimental silages were made from seven pasture species at different stages of maturity. In vivo dry matter, organic matter, and energy digestibilities of the silages were determined at restricted and ad libitum intake levels on standardized pairs of Merino wethers. In vitro dry matter digestibility determinations were made on ground frozen silage and ground oven-dried silage with and without a correction for the loss of volatile compounds during drying. Corrected in vitro dry matter digestibilities of ground oven-dried silage for a 48 hr rumen liquor digestion time gave the most accurate prediction of in vivo dry matter (r = 0.88), organic matter (r = 0.86), and energy (r = 0.74) digestibilities for restricted intake levels. In vitro digestibilities of ground frozen silage more accurately predicted in vivo digestibilities than did in vitro digestibilities of ground oven-dried silage without the correction for volatile losses. In vivo dry matter and organic matter digestibilities were highly correlated (v = 0.97), but both were poorly correlated with in vivo energy digestibilities. In vitro digestion of ground oven-dried silage with a correction for the volatile compounds lost during drying is recommended as a suitable routine determination for predicting the in vivo digestibility of silage.


1975 ◽  
Vol 15 (75) ◽  
pp. 471 ◽  
Author(s):  
J Clark

The digestibilities of the dry matter (DDM) of 16 herbages and 22 mixtures of grain and hay of known in vivo digestibility were determined by a two-stage in vitro technique, with inocula obtained from sheep fed either hay or a diet of 70 per cent barley and 30 per cent hay; both diets contained 12 per cent crude protein. The in vitro digestions were conducted with or without the addition of ammonium sulphate. The correlations between in vivo and in vitro digestibilities were higher for the herbages and the mixtures with inoculum from sheep fed hay, than with that from sheep fed barley and hay. Adding ammonium sulphate to either inoculum lowered the in vivo-in vitro correlation for the mixtures containing grain but improved the correlation for the herbage samples. The variability between replicate in vitro determinations was not reduced by adding ammonium sulphate to the inoculum from sheep fed hay but was increased for the inoculum from sheep fed a mixture of barley and hay.


1987 ◽  
Vol 67 (2) ◽  
pp. 573-576 ◽  
Author(s):  
E. V. VALDES ◽  
G. E. JONES

A two-stage cellulase-pepsin technique (CS) was compared with the two-stage rumen inoculum-pepsin (IVDMD) method to predict in vivo dry matter digestibility (in vivo DMD) in grasses (n = 30) and legumes (n = 25). Comparisons of CS with IVDMD in whole-plant corn (n = 186) were also conducted. There were significant correlations (P < 0.01) between CS and in vivo DMD and between CS and IVDMD in all forages. The coefficients of determination (r2) and residual standard deviations for the prediction of IVDMD by CS varied between 0.76 and 0.90 and 2.5 and 3.4, respectively. Key words: Digestibility (in vitro), digestibility (in vivo), fungal cellulases, forage


1959 ◽  
Vol 53 (2) ◽  
pp. 192-197 ◽  
Author(s):  
D. M. Walker

1. An in vitro apparatus is described for measuring the percentage dry-matter digestibility of roughages.2. Samples of hay, dried herbage, oat hay and oat straw were tested in vitro and the values obtained compared with in vivo results obtained with sheep.


1972 ◽  
Vol 23 (1) ◽  
pp. 25 ◽  
Author(s):  
DC Brown ◽  
JC Radcliffe

Twenty experimental silages were made from seven pasture species at different stages of maturity. In vivo dry matter, organic matter, and energy ad libitum intakes and digestibilities of the silages were determined with standardized pairs of Merino wethers. The following chemical characteristics of the silages were measured: nitrogen, ammonia nitrogen, total titratable acids, acetic, propionic, butyric, and lactic acids, total volatiles lost during oven drying, lactic acid as a percentage of the total organic acids, pH, acid pepsin dry matter disappearance, dry matter content, and in vitro digestibility and rate of digestion. When all 20 silages were considered, energy intakes on a body weight basis were significantly related to silage pH (r = 0.55) and rate of in vitro digestion (r = 0.58). When the five legume silages were removed from the analysis and only the 15 grass-dominant silages were considered, dry matter intakes were significantly related to acetic (r = –0.57) and propionic acid (r = –0.55) concentrations. Multiple regression analyses did not significantly increase the accuracy of predicting intake. The results suggested that silage intake was negatively related to the degree of fermentation that occurred during the ensiling process.


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.


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.


1980 ◽  
Vol 60 (2) ◽  
pp. 367-378 ◽  
Author(s):  
R. J. BOILA ◽  
J. D. ERFLE ◽  
F. D. SAUER

The two-stage Tilley and Terry technique (incubation with rumen fluid followed by an acid-pepsin digest), used to estimate dry matter (DM) digestibility of forages in vitro, was evaluated with oven-dried corn silage as a substrate. The effect of weight of substrate (100–3000 mg), continuous shaking of incubations for the period of incubation with rumen fluid, number of bacteria present in the inoculum, and the contribution of bacterial dry matter to residual feed DM was measured. Percent dry matter digested decreased linearly as weight of substrate per incubation tube increased. Continuous shaking, as opposed to intermittent mixing (twice daily) during incubation with rumen fluid, increased the rate of DM disappearance and resulted in higher digestibility coefficients. Both the volume of inoculum and the number of bacteria present in that volume of inoculum influenced the percent DM digested. Bacteria contribute weight to residual feed DM unless steps are taken to remove them by centrifugation or solubilization.


1996 ◽  
Vol 47 (4) ◽  
pp. 539 ◽  
Author(s):  
GR Thorniley ◽  
MD Boyce ◽  
JB Rowe

An experiment was conducted to investigate why virginiamycin reduces feed intake when it is first included in diets fed to sheep and cattle. Sheep were dosed daily with various amounts of virginiamycin, and measurements were made of both in vitro and in vivo dry matter digestibility and of blood gastrin concentrations. Virginiamycin decreased feed intake and there was some evidence that the effect was dose related. Dry matter digestibility was reduced by doses of virginiamycin >80 mg/day. Although highly correlated with feed intake, digestibility did not seem to be the sole factor influencing feed intake. Blood gastrin concentration was not significantly affected by virginiamycin and was not correlated with feed intake.


1974 ◽  
Vol 57 (5) ◽  
pp. 1224-1226
Author(s):  
Surendra K Arora ◽  
Bhagwan Das

Abstract A simple device, a fibrometer, has been devised for measuring the bulk value of a forage sample. The bulk value obtained by using the fibrometer was significantly and negatively correlated with acid-detergent fiber and cellulose. It was also significantly and positively correlated with in vivo and in vitro dry matter digestibility. This method reduces the effort required to analyze a large number of breeding materials for nutritional value and is also economical.


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