A comparison of methods for determining the digestibility of rations for sheep

1977 ◽  
Vol 17 (88) ◽  
pp. 746 ◽  
Author(s):  
A Nik-Khah ◽  
J Beard

The dry matter digestibilities (DMDs) of three sheep rations, namely hay, hay and pelleted concentrates and the pellets only were determined in vivo, by an in vitro technique and four modifications to it, and by using a summative equation. The in vivo DMDs were 57.2,63.2 and 71 .1 per cent for the hay, hay and pellets, and pellets respectively. The basic in vitro two stage technique over-estimated these by 5.1, 4.8 and 6.5 units respectively. The DMDs of the modifications to the basic in vitro technique did not differ from those resulting from the basic procedure except in one instance where the in vitro DMD of hay (57.9) was significantly lower (P < 0.01). The summative equation gave values that were 3.5, 2.5 and 3.7 units greater than the in vivo DMDs.

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.


Author(s):  
Abdulhameed Jimoh ◽  
Job Olutimehin Atteh

The need for rapid test in evaluation of feedstuffs in poultry nutrition cannot be overemphasized. Such test must however be able to replace exactly the response in the animal concern. This study was conducted to determine the suitability of In vitro technique in predicting the In vivo response of poultry to enzyme supplemented feedstuffs. Rice husk was used in a Completely Randomized Design with individual and cocktail of enzymes for both In vitro and In vivo trials. Three exogenous enzymes namely a xylanase, a multipurpose and a phytase were used individually, pairwise and altogether with the feedstuff to constitute the treatments namely T1, T2, T3, T4, T5, T6, T7, and T8. Each treatment was replicated thrice for both In vitro and In vivo trials. The In vitro trial was done to simulate the chicken digestive system while the In vivo trial was done using the intubation method. Parameters measured for both trials were digestibility values for dry matter, crude protein, ether extract, crude fiber and fiber fractions. All data collected were statistically analyzed using Analysis of Variance procedure and treatment means were separated using Duncan Multiple Range Test. Correlation analysis was carried out to compare the results of both trials.  Results show that enzymes individually and as cocktails significantly improved the digestibility of parameters for both In vitro and In vivo trials. Cocktails of enzymes were significantly better than the individual enzymes for dry matter and crude fiber digestibility for both In vitro and In vivo trials. Correlation analysis shows positive correlation (r=0.99, r=0.96, r=0.94, r= 0.86, r=0.78) between In vitro and In vivo trials in most of digestibility values for the rice husk. It was concluded that In vitro trial can be used as both criterion and replacement for In vivo trial when determining the efficacy of exogenous enzymes in poultry nutrition.


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


1977 ◽  
Vol 57 (2) ◽  
pp. 279-288 ◽  
Author(s):  
S. O. THORLACIUS

Digestibility and intake of diets containing 8, 28, 48 or 68% ground wheat straw plus ground crested wheatgrass and rapeseed meal, and diets containing 33, 48, 63 and 78% ground crested wheatgrass plus barley and rapeseed meal was measured with four yearling wethers per diet. Digestible energy (DE) content ranged from 2.07 to 2.95 kcal/g dry matter (DM) and dry matter digestibility (DMD) (%) from 48.7 to 71.1%. Regression of DE intake y (kcal/w0.75kg/d) on DE content (x) was curvilinear; y = −2,133 + 1,626x − 277.9x2, r = 0.996, P < 0.01, SE = ± 7.3. There was also a curvilinear relationship between diet density, as fed, (x) g (DM)/ml and DMD (%), y = 9.057 + 364.1x − 530.0x2, r = 0.970, P < 0.01, SE = ± 2.4. A linear regression equation was calculated over the DE range (2.07–2.52) for which there was an obvious increase in DE intake with increasing diet DE content; y = −700.6 + 361x, r = 0.994, P < 0.01, SE = ± 9.4, y = DE intake (kcal/w0.75kg/d), x = DE [kcal/g (DM)]. Using this regression equation and assuming a linear increase in DE intake with increase in diet DE content up to a point at which the apparent energy demand of the animal is satisfied gave a more accurate prediction of DE intake than when the curvilinear regression equation, y = −2,133 + 1,626x − 277.9x2, was used empirically. Accuracy of the prediction was further improved by expressing DE/unit ration volume instead of per unit DM. The sheep used in the present experiments had an apparent energy demand of 230 kcal/w0.75kg/day which was met at diet DE contents above 0.48 kcal/ml or 2.6 kcal/g (DM). There was a high correlation between in vivo DE content of the diet, y [kcal/g (DM)] and in vitro (x) digestible organic matter content, x, (%), r = 0.991, P < 0.01, y = 0.38 + 0.037x, SE = ± 0.04.


1975 ◽  
Vol 23 (1) ◽  
pp. 3-9
Author(s):  
S. Tamminga ◽  
C.J. van der Koelen

1. Grass from the same sward was ensiled without additive, with 14.6 g formic acid/100 g crude protein or 10.8 g formic acid and 10.6 g formaldehyde/100 g crude protein. Similar grass was dried and pelleted. Drying or ensiling with the mixture reduced solubility of N in the preserved grass but formic acid increased it, and ensiling without additive increased it even more. Apparent digestibility of N in the rumen of cows tended to decrease with decrease in solubility. Digestibility in vitro of the mixed diet given to the cows, calculated from digestibility of the separate components, agreed well with the values in vivo for diets with silages, but was high for that with dried grass. (Abstract retrieved from CAB Abstracts by CABI’s permission)


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.


1997 ◽  
Vol 1997 ◽  
pp. 197-197
Author(s):  
R. Sanderson ◽  
S.J. Lister ◽  
A. Sargeant ◽  
M.S. Dhanoa

The objectives of this study were a) to examine the effect of particle size and silage dry matter (DM) content on the rate and pattern of fermentation of fresh silages in vitro as an aid to modelling the in vivo situation and b) to compare the rate and pattern of fermentation of fresh silage samples with those obtained for freeze-dried material.


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.


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