Measurement of the rate and extent of cell wall degradability in forages; a comparison of three methods

1995 ◽  
Vol 1995 ◽  
pp. 111-111
Author(s):  
E. R. Deaville ◽  
D. I. Givens

Forage cell wall content (CWC), accounting for 400 to 600 g kg-1 dry matter (DM) (Van Soest, 1982) and its rumen degradability (CWD) are major factors influencing the animal's energy supply from forages. Therefore, in order to maximise the nutritional potential of forages for ruminants, the ability to accurately and rapidly measure CWD is crucial. This is becoming increasingly important as feed evaluation methods move towards assessing nutrient supply. While the measurement of CWD is largely based on the polyester bag technique an experiment was undertaken to study the potential of measuring CWD in vitro for different forage types.Three methods of measuring CWD were compared using four samples each of grass (G), grass silage (GS), maize silage (MS) and straw (S) in a factorial design. The methods were; 1) fresh (undried) forage, chopped to 1 cm lengths using an homogeniser, was incubated in the rumens of sheep in polyester bags (pore size 43um) for different lengths of time (0, 3, 8, 16, 24, 45 and 72h).

1995 ◽  
Vol 1995 ◽  
pp. 111-111
Author(s):  
E. R. Deaville ◽  
D. I. Givens

Forage cell wall content (CWC), accounting for 400 to 600 g kg-1 dry matter (DM) (Van Soest, 1982) and its rumen degradability (CWD) are major factors influencing the animal's energy supply from forages. Therefore, in order to maximise the nutritional potential of forages for ruminants, the ability to accurately and rapidly measure CWD is crucial. This is becoming increasingly important as feed evaluation methods move towards assessing nutrient supply. While the measurement of CWD is largely based on the polyester bag technique an experiment was undertaken to study the potential of measuring CWD in vitro for different forage types.Three methods of measuring CWD were compared using four samples each of grass (G), grass silage (GS), maize silage (MS) and straw (S) in a factorial design. The methods were; 1) fresh (undried) forage, chopped to 1 cm lengths using an homogeniser, was incubated in the rumens of sheep in polyester bags (pore size 43um) for different lengths of time (0, 3, 8, 16, 24, 45 and 72h).


2002 ◽  
Vol 2002 ◽  
pp. 115-115
Author(s):  
R.M. Kirkland ◽  
R.W.J. Steen ◽  
F.J. Gordon ◽  
T.W.J. Keady

The inclusion of maize silage in grass silage based diets may offer the potential to improve productivity on farms due to associative effects resulting from mixed-forage diets on nutrient supply to the animal. The objective of the present study was to examine the effects on dry matter (DM) and metabolisable energy (ME) intakes of beef cattle of offering forage mixtures comprising grass and maize silages of differing qualities.


1988 ◽  
Vol 68 (3) ◽  
pp. 787-799 ◽  
Author(s):  
V. GIRARD ◽  
G. DUPUIS

In view of the large variation found in plant cell wall digestibilities with ruminants, an attempt was made to group 124 feeds into different lignification classes (clusters) on the basis of chemical characteristics. Each feed cluster was described using a structural coefficient [Formula: see text] that related the potentially digestible fiber (PDF, %) to the ratio between lignin and cell wall volume. The optimum number of clusters was determined iteratively by performing a regression of the apparent digestibility of dry matter at maintenance level (DDM1, %) against the PDF and cell soluble (SOL, %) contents of feeds. The [Formula: see text] coefficients varied from 0.05 (grains, N = 13) to 1.85 (corn silage, N = 3) and increased with the maturity of the grasses from 0.88 (legumes, vegetative cool season grasses, N = 26) to 1.33 (mature, cool season grasses, N = 19). Predicted PDF were closely correlated (r > 0.9, P < 0.01) to in vitro cell wall disappearances (IVCWD). Apparently digestible cell wall in four grasses and four legumes increased linearly with 96-h IVCWD and standard error (SE) was similar to the SE of predicted apparent digestible SOL from SOL concentrations. Assuming that similarity between SE could be also observed in larger samples, PDF and SOL were used in summative equations to predict apparent dry matter digestibility. DDM1 discounted for intake (DDM1 – 4, %) was regressed against SOL and PDF concentrations of 87 feeds:[Formula: see text]with ds and df, the true digestibilities of SOL and PDF. Estimates of ds and df were 0.98 and 0.95 for a zero-production (maintenance) level of intake, and 0.91 and 0.79 for an intake level four times maintenance. Since the true digestibility of the PDF component was only 4% – 13% lower than that of the cell soluble component, the concentration of PDF in cell wall was the major determinant in the variation in apparent digestibility of forages. Key words: lignin, neutral detergent fiber, true digestibility, cluster analysis, feeds


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.


1996 ◽  
Vol 1996 ◽  
pp. 213-213
Author(s):  
E.D. Mackintosh ◽  
R.H. Phipps ◽  
J.D. Sutton ◽  
J. Wilkinson

Rusitec (Czerkawski and Breckenndge, 1977) lias been widely used to study factors which affect rumen fermentation such as monensin, monensin-propionate, abierixin, calcimycin and Aspergillus oryzae (Bogaert et al., 1990; Newbold et al., 1993). Monensin is a grain-positive ionophore which modifies rumen fermentation. The objective of the current study was to determine the effect of monensin on molar proportions of volatile fatty acid (VFA) produced from diets which varied in foragexoncentrate ratio.Four Rusitec vessels (800 ml) were used in an extended Latin Square design with 2 blocks, 2 treatments and 3 periods, each lasting 14 days. To initiate each period, inocula was recovered from the same lactating Holstein-Friesian cow (∽650 kg). All vessels received 15 g DM/day of a complete diet which contained maize silage, grass silage, NaOH treated wheat grain and a protein supplement in three foragexoncentrate ratios; 25:75 (L), 50:50 (M) and 75:25 (H).


2020 ◽  
Vol 42 ◽  
pp. e48272
Author(s):  
Maikon Figueredo Lemos ◽  
Alexandro Pereira Andrade ◽  
Pedro Henrique Ferreira da Silva ◽  
Camila Oliveira Santos ◽  
Caio Felipe Barros Souza ◽  
...  

The aim of this study was to evaluate nutritional value, fermentation losses, and aerobic stability of elephant grass silage (Pennisetum purpureum Schum.) treated with exogenous fibrolytic enzymes. The experiment was conducted in a completely randomized design with four replicates (experimental silos) and five levels of fibrolytic enzymes (0, 1.5, 3.0, 4.5 and 6.0%). For this, the elephant grass was ensiled at 70 days of age in plastic buckets with 20L capacity. Silos were opened 60 days after sealing. Analyses were made for chemical composition, in vitro dry matter digestibility (IVDMD), effluent losses (EL), gas losses (GL) and dry matter recovery (DMR), as well as the aerobic stability of the silage. Data were analyzed with PROC REG of SAS® University, at 5% probability. There was an increase in IVDMD content (p < 0.0001) and reduction in NDF and ADF contents (p < 0.0001) according to enzyme levels. These results were related to the increase in the degradation of fiber fractions. There were higher EL (p = 0.0062) as a function of enzyme levels and aerobic deterioration after silo opening, at all levels tested. Thus, it can be concluded that the exogenous fibrolytic enzymes change the chemical composition of elephant grass silage, and increase its digestibility and nutritional value. Moreover, when used alone as an additive, fibrolytic enzymes are not able to recover all dry matter of this silage (with effluent and gas losses), and are not able to maintain aerobic stability in the first hours after opening the silos.


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.


1980 ◽  
Vol 31 (3) ◽  
pp. 243-250 ◽  
Author(s):  
K. Aston ◽  
J. C. Tayler

ABSTRACT1. Experiment 1. Six treatment groups of one British Friesian and four South Devon × British Friesian bulls, initially 432 kg mean live weight and aged 491 days, were offered individually maize or grass silage ad libitum plus 0, 5 or 10g barley dry matter per kg live weight daily for 80 days. The silages had similar digestible dry matter and estimated metabolizable energy contents but the grass silage contained more ammonia and acetic, propionic and butyric acids. Mean values for groups receiving respectively maize and grass silage diets were for dry-matter intake 17·7, 20·3, 20·4 and 13·0, 16·6, 18·7 g/kg live weight and for live-weight gain 1·00, 1·32, 1·46 and 0·65, 0·98, 1·22kg/day. Significantly more maize than grass silage dry matter was eaten when the silages were given alone and dry-matter intakes, live-weight and carcass gains were greater for maize silage diets. Dry-matter intake, live-weight and carcass gains, efficiency of feed use and carcass quality significantly improved when barley was given.2. Experiment 2. Six groups of five British Friesian bulls, initially 418 kg mean live weight and aged 474 days, were offered individually maize silage ad libitum with either urea or one of two quantities of aqueous ammonia mixed in at the time of feeding, plus 0 or 5 g barley dry matter per kg live weight daily for 90 days. The urea and ammonia-treated silages contained 125, 124 and 148 g crude protein per kg dry matter respectively, with pH values of 3·8, 3·9 and 4·3, and when given alone or with barley mean daily intakes (g dry matter per kg live weight) were 17·1, 18·6 for urea-treated silage diets, and 17·8, 18·8 and 16·9, 19·1 respectively for ammoniatreated silage diets. Live-weight gains were 0·69, 0·94, 0·63, 1·09, 0·64 and 1·07 kg/day. Ammonia treatment had no effect on intake or live-weight gain. Live-weight and carcass gains and carcass quality improved when barley was given.3. The maize silage offered in Experiment 1 contained similar metabolizable energy but more starch than that in Experiment 2 and was used more efficiently for live-weight gain.


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