Estimation of fermentable energy by the automatic in vitro gas production technique for a selection of feedstuffs incubated alone and in combination

1998 ◽  
Vol 1998 ◽  
pp. 69-69
Author(s):  
S. Fakhri ◽  
A. R. Moss ◽  
D.I. Givens ◽  
E. Owen

The gas production (GP) technique has previously been used to estimate the gas volume (fermentable energy (FE)) of compound feed ingredients for ruminants (Newbold et al., 1996). It was shown that the FE content of feed mixtures was represented by the combination of the total gas from the incubation of the individual feeds. However this additivity might not be consistent throughout the incubation period. The objectives were to test whether 1. other GP parameters give better estimates of FE for simple mixtures and are they additive; 2. whether organic matter apparently degraded in the rumen (OMADR) explain differences in GP; and 3. to find out if there are any other better measures than OMADR for estimating FE.

1998 ◽  
Vol 1998 ◽  
pp. 69-69 ◽  
Author(s):  
S. Fakhri ◽  
A. R. Moss ◽  
D.I. Givens ◽  
E. Owen

The gas production (GP) technique has previously been used to estimate the gas volume (fermentable energy (FE)) of compound feed ingredients for ruminants (Newbold et al., 1996). It was shown that the FE content of feed mixtures was represented by the combination of the total gas from the incubation of the individual feeds. However this additivity might not be consistent throughout the incubation period. The objectives were to test whether 1. other GP parameters give better estimates of FE for simple mixtures and are they additive; 2. whether organic matter apparently degraded in the rumen (OMADR) explain differences in GP; and 3. to find out if there are any other better measures than OMADR for estimating FE.


1998 ◽  
Vol 1998 ◽  
pp. 60-60
Author(s):  
U.R. Altaf ◽  
R. Mauricio ◽  
F.L. Mould ◽  
T. Smith ◽  
E. Owen ◽  
...  

A previous study (Mauricio et al., 1998) with 12 forage substrates (straw, hay and dried grasses) showed a high correlation between rumen liquor and faeces for total gas production and in vitro organic matter digestibility (OMD). However parameters estimated using faecal inoculum were generally lower man when using rumen liquor. To confirm this observation, a second study was conducted using maize silage and silages made from maize plant fractions.


2014 ◽  
Vol 54 (10) ◽  
pp. 1662
Author(s):  
G. Antúnez ◽  
C. Cajarville ◽  
A. Britos ◽  
A. González ◽  
J. L. Repetto

The aim of this study was to evaluate the fermentation activity of ruminal inoculum from cattle fed fresh pasture and supplemented or not with corn grain at different daily frequencies. Twenty heifers with ruminal catheters were randomly assigned to four treatments. Animals were fed pasture ad libitum and non-supplemented (T0) or supplemented with corn grain at 1% of bodyweight offered in one (T1), two (T2) or eight (T8) meals per day. After 20 days of adaptation, ruminal inoculum of each heifer was used to evaluate fermentation activity by the in vitro gas-production technique, using alfalfa, white clover or ryegrass as substrates. Gas production was measured at 2, 4, 6, 8, 10, 12, 18, 24, 48, 72 and 96 h from the beginning of incubation. Data were fitted to an exponential model and potential gas volume, fractional rate of gas production and lag time were analysed by PROC MIXED, considering the effect of treatment and substrate, and their interaction. The three parameters were affected by the substrate. Supplementation frequency did not affect the potential gas volume or the fractional rate of gas production. An interaction between treatment and substrate was detected (P < 0.01) on lag time, but only when ryegrass was used as the substrate. In conclusion, increasing the frequency of supplementation did not show benefits for the fermentation activity of ruminal inoculum, at least when the type of pasture used in this experiment was supplemented with corn at 1% of bodyweight.


1997 ◽  
Vol 64 (1) ◽  
pp. 71-75 ◽  
Author(s):  
M. Blümmel ◽  
P. Bullerdieck

AbstractThe need to complement in vitro gas production measurements with residue determination is demonstrated by the recalculation and reassessment of published data on in vitro gas production, in sacco degradabilities and voluntary dry matter intake (DMI). The in sacco degradability — gas volume ratio was determined at 24 and 48 h of incubation, termed partitioning factor (PF) and combined with rate and extent parameters of in sacco degradability and in vitro gas production to predict DMI. In vitro gas production and in sacco degradability characteristics (a + b) and c as described by the equation y = a + b(1−ect) explained 0·373 and 0·668 respectively of the variation in DMI of 19 legume and grass hays. The complementation of gas production parameters by the PF24 increased the R2 value to 0·744 with PF24 accounting for 0·407 of the variation in DMI, the rate of gas production (c) for 0·218 and the extent of gas production (a + b) for 0·119 of the variation in DMI. As a single parameter, PF48 showed the highest correlation (R2 = 0·597) with DMI but the combination of PF4S with rate and extent of in sacco or in vitro gas production measurements did not improve the correlation further, probably due to an intercorrelation between rates of fermentation and PF4S. Hays which were degraded at faster rates had higher PF values indicating proportionally higher microbial yield and lower short-chain fatty acid production per unit substrate degraded. Generally, hays with high in sacco degradabilities but proportionally low gas production i.e. hays with high PF values showed higher DMI.


Author(s):  
N.D. Meads ◽  
R. Tahmasbi ◽  
N. Jantasila

Greenhouse gas (GHG) emissions from livestock are an important consideration in environmental science. Estimating GHG production can be problematic at a farm or animal level, and requires controlled conditions to produce real data. An in vitro gas production technique (IVGPT) was developed to evaluate forage-based total mixed rations in digestion kinetics and GHG production. Two hundred and sixty samples of complete mixed rations (MR), which included a pasture component used in commercial lactating dairy herds, were collected around NZ across three calendar years, 2017-2019. Twenty of the 260 samples were 100% total mixed rations (TMR) with no pasture content. The samples were submitted for proximate analysis as well as IVGPT to generate GHG production figures. The results showed an average total gas production (TGP) of 129.82 ml/g dry matter (DM), 78.6% true digestibility (TDMD), 125.06 mg/g DM microbial biomass (MB), 20.16 g CH4/kg DM, and 12.8 MJME/kg DM. The average nutrient composition was dry matter (DM) 31.55%, crude protein (CP) 21.85%, neutral detergent fibre (NDF) 44.35%, and starch 7.03%. The IVGPT CH4 production was negatively correlated to NDF (r=-0.312), ADF (r=-0.193), TGP (r=-0.216), and was positively correlated with TDMD (r=0.250), apparent digestibility (ADMD) (r=0.614), starch (r=0.117) and volatile fatty acids (r=0.538). The MR diet showed a strong positive relationship with ADMD digestibility (P=0.01) and a negative relationship with fibre content (NDF, P=0.01 and ADF, P=0.01). However, CH4 production reduced linearly with increasing TGP (P=0.01). The results indicated that a greater CH4 production may be related to higher digestibility of mixed ration.


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