Sacco Digestibility Research Articles

Pengaruh Lama Fermentasi Jerami Jagung Menggunakan Kapang Trichoderma Harzianum terhadap Kandungan Serat dan Kecernaan In Sacco

Corn straw is an alternative feed from agricultural waste that can be widely used by farmers as ruminant feed. This study aims to determine the fiber content and in sacco digestibility of corn straw fermented with Trichoderma harzianum. The design of this experiment was Completely Randomized Design with 5 treatments and 4 replications. The samples were treated with 5 length of fermentation time, namely: 0 (control) , 4, 8, 12 and 16 days. Nylon bag technique was applied to evaluate the sample degradation. Corn straw that has been ground to a size of 2 mm, taken as much as 5-6 g, then put into a nylon bag and incubated in the cattle rumen for 72 hours. The results showed that corn straw fermentation using Trichoderma harzianum increased the content of NDF, ADF and the degradation of ADF but dit not increased the NDF and hemicellulose digestibility. In conclusion, the best fermentation time is 12-16 days under aerobic conditions.

The Impact of Ensiling at Different Moisture Contents on Germinability and Viability of Selected Weed Species’ Seeds

Weeds are an increasingly significant issue inhibiting agricultural production worldwide. Forage conservation could form part of an integrated weed management program if ensiling killed weed seeds. In Experiment 1, seeds of five grass (Hordeum spp., Bromus diandrus, Bromus hordeaceum, Lolium rigidum and Vulpia spp.) and two broad-leaved temperate weed species (Echium spp. and Raphanus raphanistrum), that were either untreated, ensiled in pasture (Trifolium subterranean/Lolium rigidum mixture) forage for a minimum of three months, underwent 48 h in sacco digestion in steers or ensiled prior to digestion were tested for germinability and viability. In Experiment 2, seeds of eight tropical weed species (Cenchrus ciliaris, Rumex spp., Bidens pilosa, Sorghum halepense, Urochloa panicaoides, Paspalum dilatatum, Brachiara eruciformis and Choris truncata) were ensiled in Sorghum bicolor forage. In Experiment 3, L. rigidum and R. raphanistrum seeds were ensiled in either Medicago sativa forage wilted to 336.9, 506.5 or 610.7 g/kg dry matter; or in chaff to which water or water plus acid was added at rates to achieve 350, 450 or 550 g/kg dry matter content with lactic plus acetic acid added in the ratio of 3:2 at 80, 45 or 10 g/kg DM, respectively. In Experiment 4, L. rigidum and R. raphanistrum seeds were ensiled in cotton wool to which water or water plus acid was added at the same rates as in Experiment 3. Germinability of all seeds following ensiling was substantially reduced or nil. The extent of the reduction varied with species and experiment. In sacco digestion reduced germinability in Experiment 1, but to a lesser extent than ensiling; while ensiling plus digestion reduced germination rates to 0%.

139 In sacco and in vivo digestibility of silages in horses

The gold standard method for measuring digestibility of feedstuffs is by total collection of feces. An alternative method is the in sacco technique which provide information on both digestibility and digestion kinetics of a feed. The in sacco technique is commonly used in feedstuff evaluation systems for ruminants. Only few studies have used the technique in horses, but further validation against in vivo studies is needed. The objective of the study was to determine if the in sacco technique can be used to measure digestibility in horses. Five cecum cannulated Norwegian coldblooded trotters (body weight 550 ± 75 kg) were used in a 22 d study consisting of 18 d of diet adaptation followed by 4 d of total collection of feces. Horses were fed 24.3 kg of a late harvested silage (LHS, dry matter (DM) 31.0%, neutral detergent fiber (NDF) 59.6% of DM) fed in 3 equal meals at 0800, 1400 and 2000 h. The apparent total-tract digestibility (ATTD) of LHS was estimated by total collection of feces over 4 consecutive days. Before the collection period, in sacco digestibility was estimated of the LHS and an early harvested silage (EHS, DM 26.0%, NDF 28.6% of DM) using the in sacco technique (bag size 6 × 15 cm, 5.13 mg feed/cm 2 , pore size of 36 μm). The EHS and LHS were dried, ground to 1 mm and 1 g was added to in sacco bags. Two bags of each feedstuff were fastened to a 78 cm long string with rubber bands and incubated in the cecum for 0, 2, 4, 8, 16 and 24 h, then washed, dried for 48 h and weighed to determine DM loss after incubation. The in sacco digestibility was modeled in SAS according to D = A tB (e −Ct ) , where D is the digestibility through time t, A is the soluble fraction of the feedstuff and curve interception, B is the potential digestibility of the insoluble fraction, and C is the digestion rate of B. The potential digestibility (A+B) of the LHS was compared with EHS and to the ATTD of LHS in SAS using a paired t -test and considered significant if P < 0.05. The ATTD of DM for LHS (57.0% ± 0.49) was not different ( P = 0.22) from the potential digestibility (58.4% ± 2.16) measured with the in sacco technique. The A, B and C values were 33.6, 24.8 and 0.096 for the LHS and 64.2, 28.6 and 0.178 for the EHS. The potential digestibility for EHS (92.8% ± 0.42) was higher ( P < 0.001) than the LHS as expected and show that the technique can differentiate between feedstuffs. In conclusion, the in sacco technique resulted in similar results as in vivo ATTD of LHS and it is a promising technique for estimating digestibility of individual feedstuffs in horses. However, the technique needs to be developed further and validated using other feedstuffs and mixed diets.

Effect of ensiling and in sacco digestion on the viability of seeds of selected weed species

SummaryThe germinability and viability of mature seeds of five grass (Hordeum spp., Bromus diandrus, Vulpia spp., Avena fatua and Lolium rigidum) and seven broad‐leaved weed species (Echium spp., Physalis hederifolia, Solanum elaeagnifolium, Raphanus raphanistrum, Marrubium vulgare and Malva parviflora) that were either untreated, ensiled for a minimum of three months, underwent 48 h in sacco digestion in steers or ensiled prior to digestion were tested for germinability and viability. Ensiling and digestion both reduced seed viability, although the extent varied with species. The effect of ensiling was generally greater compared with digestion and differed between years for some species. Ensiling or ensiling plus digestion rendered all seeds of Hordeum spp., B. diandrus, Vulpia spp., A. fatua, Echium spp., P. hederifolia (in one year only), S. elaeagnifolium, R. raphanistrum and M. vulgare non‐viable; ensiling and ensiling plus digestion reduced viability of L. rigidum by 74.4% and 92.7% respectively. Viability of M. parviflora displayed the greatest tolerance to damage, with seed viability reduced on average by 31.4%, 27.6% and 27.4% for ensiling, digestion and ensiling plus digestion treatments respectively. These results indicate that ensiling can provide an effective non‐chemical weed management option, as a component of an integrated weed management package, for certain weed species responsible for significant crop and pasture production losses in Australian and world temperate and Mediterranean agricultural systems.

Effect of stage of harvest on the yield, chemical composition, in vitro and in sacco digestibility of hybrid napier (Penniserum purpureum) variety APB N1

APBN1, a variety of hybrid napier was analysed at five stages of harvest (30, 40, 45, 50 and 60 days) for yield, leaf to stem ratio, chemical composition, in vitro dry matter digestibility, in sacco dry matter and protein degradation to find out optimum stage of harvesting. The yield of green fodder, dry matter (DM) and crude protein (CP) (MT/ ha/year) of forage harvested at 30, 40, 45, 50 and 60 days of growth ranged from 274.68 to 387.95, 47.35 to 98.81, 7.44 to 11.45, respectively. Highest (P less than 0.05) CP yield (11.45 MT/ha) and nitrogen free extract content (46.12%) was observed at 45 d of growth. Crude protein (15.72 to 11.34%), ether extract (3.65 to 2.26%) decreased, whereas total ash (10.88 to 13.86%), crude fibre (23.81 to 29.88%) and acid insoluble ash (3.92 to 5.14%) levels increased when forage was allowed to grow from 30 to 60 d. Similarly, NDF, ADF, hemicellulose, cellulose, lignin and silica levels also increased gradually as plant matures. The in vitro dry matter digestibility was maximum (57.87%) at 30 d and minimum (51.40%) at 60 d of growth. Effective dry matter and protein degradability decreased from 55.80 to 43.78 and from 38.30 to 33.17 per cent, respectively as plant matured from 30 to 60 days. The insoluble but degradable protein fraction ‘b’ was highest (77.07%) at 45 d of growth. Based on the biomass yield, leaf to stem ratio, chemical, in vitro and in sacco evaluation, the optimum stage of harvesting for APBN1 forage was found to be at 45 d of growth.

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

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 &lt; 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.

VLIV VEGETAČNÍHO STADIA VOJTĚŠKY SETÉ NA CHEMICKÉ SLOŽENÍ A IN SACCO STRAVITELNOST ORGANICKÉ HMOTY

The influence of the stage of maturity of alfalfa on the chemical composition and in sacco digestibility was studied in a laboratory experiment. Alfalfa plants were analysed in 8 vegetation stages harvested in regular intervals before the beginning of bud setting until the fall of blossoms. The contents of nitrogenous substances, fat, crude fibre, ADF, NDF, Ca, P, Na, K and Mg were determined in the samples, and using the in sacco method also the organic matter digestibility in the rumen. Further we assessed the energy content and calculated the N−free extractives (BNLV) value. In some stages the chemical changes were monitored in the whole plant. It was discovered that during vegetation there was a statistically significant increase in the crude fibre content and in the ADF and NDF fractions and a reduction in nitrogenous substances. A strong negative correlation was detected between the stage of maturity of alfalfa and content of crude protein and net energy for lactation (r = −0.97 and r = −0.92, respectively). In the individual stages of vegetation the differences in the content of nitrogenous substances, fibre and fat were statistically significant (P &lt; 0.05). The statistically highest content of crude protein (28.97%) was detected in the first stage before bud setting and the lowest (11.97%) in the stage after the fall of blossoms. Later vegetation also had a stronger depressive effect on the content of fat and NEL. The organic matter digestibility (P &lt; 0.05) was the lowest in alfalfa in the last stage of sampling (62.6%) when it reached a mere 85.99% of the digestibility at the beginning of bud setting. The highest organic matter digestibility (72.80%) was detected in a sample of young alfalfa prior to bud setting. In the experiment we confirmed a strong and negative correlation (r = −0.97) between the crude fibre content and organic matter digestibility. The correlation was also strong between the stage of maturity of alfalfa and the content of magnesium (Mg).

Effect of processing method on in sacco ruminal degradability of organic matter and nitrogen from canola seeds and in vitro intestinal nitrogen digestion of the in sacco residue

A novel crop on the Southern Plains of the United States is canola (Brassica napus L.), of which annual production has nearly doubled in the last 5 years. Although production has not exceeded the demand for oil, the question has arisen as to its supplemental value for cattle grazing the rangeland adjacent to production areas. In an experiment, six seed processing methods were evaluated by in sacco digestion of organic matter and nitrogen and in vitro intestinal in sacco residue: (1) whole seeds with no processing; (2) seed coats scarified in a pneumatic seed scarifier; (3) ground in a four-knife mill; (4) unprocessed seed rolled to 0.5 mm thick; (5) seeds roasted then rolled to 0.5 mm thick; and (6) steamed then rolled to 0.5 mm thick. Processing methods were compared with a solvent-extract canola seed meal. All processing methods increased in sacco organic matter and nitrogen digestion in the rumen with ground method being the greatest (P &lt; 0.05). These results showed that the ground method produced the most (P &lt; 0.05) ruminally degraded nitrogen/kilogram of organic matter digested in the rumen (67 g) of all methods evaluated. Further, extent of in vitro nitrogen digestion (intestinal) from in sacco residue was reduced by increases in ruminal digestion. Processing methods that broke the seeds increased (P &lt; 0.05) the total extent of nitrogen digestion over whole and scarified treatments. The most limiting nutrient to augment energy intake and digestion in cattle grazing native pastures is ruminally degraded nitrogen and it seems that the most appropriate processing method is grinding to use whole canola seeds as a supplement. Other processing methods evaluated either increased processing cost or increased the ruminally undegraded nitrogen value.

Nutrient Content and in sacco Digestibility of Barley Grain and Sprouted Barley

Nutrient Content and in sacco Digestibility of Barley Grain and Sprouted Barley

Comparison of in vivo organic matter digestion of native Australian shrubs by sheep to in vitro and in sacco predictions

There is increasing interest in selection of genotypes of Australian perennial shrubs such as saltbush ( Atriplex nummularia, Atriplex amnicola and Atriplex semibaccata), orange wattle ( Acacia saligna), small-leaved bluebush ( Maireana brevifolia) and rhagodia ( Rhagodia preissii) for extensive grazing systems with sheep or cattle. A major limitation to cultivar development is that determining the in vivo organic matter digestibility of forage is expensive, time consuming and requires substantial amounts of biomass. A number of in vitro and in sacco techniques are available to predict in vivo digestibility of grasses and legumes however none of these prediction methods have been calibrated to in vivo data for Australian native shrubs. The aim of this study was to determine the in vivo digestibility of native shrub forage and compare these data to predictions using in vitro and in sacco methodologies. The hypothesis tested was that there is a linear relationship between in vivo organic matter digestibility (OMD) of Australian perennial shrub forage and a number of commonly used prediction methods. Of all the methods used, in vitro gas production from microbial fermentation showed the best relationship with in vivo OMD ( r 2 = 0.904). This method appears to be suitable for broad screening and ranking of genotypes. The in vitro pepsin-cellulase technique did not provide a good first estimate of in vivo OMD across all plant species but may be suitable to rank genotypes if data are calibrated with internal standards to manage intrinsic assay variation (step 1) followed by a correction to account for the high salt content of some plants (step 2) and a final linear correction to account for systematic overestimation of OMD of native shrubs (step 3). Further testing and refining of this third calibration step is required. The prediction of in vivo OMD using a 72 h in sacco digestion was adequate for the saltbush species but not for the orange wattle and small-leaved bluebush accessions. Prediction of in vivo OMD using the Daisy II rumen fluid digestion system was not satisfactory and there was not a statistically significant relationship between the acid detergent fibre, neutral detergent fibre or the acid detergent lignin content of the shrubs and in vivo OMD. The differences between the various laboratory-based methods to predict in vivo OMD are discussed and we hypothesise that the presence of plant secondary compounds may interfere with rumen microbial fermentation.

Effects of several levels of extracted tannin from grape pomace on intestinal digestibility of soybean meal

Grape pomace (GP) is a high tannin feed by-product produced in large amounts in many parts of the world. Tannins bind to proteins to prevent their degradation in the rumen. This tannin/protein complex may be advantageous when partially protecting high quality feed proteins from excessive rumen protein degradation. The objective of this experiment was to use a GP tannin extract to slow down rumen degradation of soybean meal (SBM) protein. After extracting the tannin compounds, SBM was treated with the extract to obtain mixtures with 0, 15, 30, 40 and 60 g/kg dry matter (DM) of tannin extract. In vitro gas production (IVGP), organic matter digestibility (OMD) and ammonia concentrations were measured, and three rumen-cannulated sheep were used to determine in sacco rumen disappearance of N. A three-step in vitro procedure was used to determine intestinal digestibility. Treating SBM with tannin extract decreased IVGP (linear and quadratic; P < 0.01) by 4.5–11%, and the in sacco digestibility of soluble N fraction (linear and quadratic effects, P < 0.01) by 15–274%. It also delayed gas production ( T/2) and increased in vitro intestinal digestibility of protein (linear and quadratic; P < 0.01) by 8.9–17.8. Tannins in GP slow down SBM protein degradation in the rumen.

Pengaruh Amoniasi Mahkota Buah Nenas (Ananas comosus Merr) Terhadap Kecernaan (In Sacco) Neutral Detergent Fiber (NDF) dan Acid Detergent Fiber (ADF)

The experiment was conducted in order to know the effect of ammoniated phineapple crown on the in sacco digestibility of neutral detergent fiber (NDF) and acid detergent fiber (ADF). Material used were phineapple crown, urea as a source of ammonia for ammoniation process and one 3 – year male Madura cattle for in sacco digestibility application. The experiment was arranged to a completely randomized design with 4 treatments and 4 replications. T0 was untreated phineapple crown, T1 was amonia treated phineaplle crown with 3 % urea, T2 was treated phineaplle crown with 6 % urea and T3 was treated phineaplle crown with 9 % urea. Result of experiment showed that ammoniation process did affect NDF and ADF digestibilities, but there was no significant effect of the urea level for NDF and ADF digestibilities.

Cernaan In Sacco Ransum Ternak Sapi yang Menggunakan Kulit Buah Jagung Amoniasi

An experiment was conducted to evaluate an improvement of corn peel with ammoniation in sacco digestibility in cow ration. Measured parameters in the current experiment were, in sacco degradation of dry matter, organic matter and crude protein. This study was assigned into completely randomized design (CRD) with 5 treatments and 4 replications. The treatments were ; R0 = 70% Forage (100% grass + 0% Corn Peel) + 30 % Concentrate, R1 = 70% Forage (75 % grass + 25% Corn Peel) + 30 % Concentrate, R2 = 70% Forage (50% grass + 50% Corn Peel) + 30 % Concentrate, R3 = 70%Forage (25% grass + 75% Corn Peel) + 30 % Concentrate, R4 = 70% Forage (0% grass + 100% Corn Peel) + 30 % Concentrate. Result of this study showed that the treatments were significantly (P&lt;0,05) influence degradation of dry matter, organic matter and crude protein. The degradation after ammoniation significantly increased and were higher than that of without ammoniation. It is concluded that ammoniation with urea of corn peel could increase degradation and could be used asforage substitution in ration.

In sacco digestion kinetics of palm kernel expeller (PKE)

Palm kernel expeller (PKE) is imported into New Zealand and fed to ruminants grazing pasture, but very little data exist on its rumen digestion characteristics when fed in conjunction with grass. Keywords: digestion kinetics, crude protein, dry matter, palm kernel expeller, pasture

Repeated ruminal dosing of Ruminococcus flavefaciens NJ along with a probiotic mixture in forage or concentrate-fed dairy cows: Effect on ruminal fermentation, cellulolytic populations and in sacco digestibility

Many studies have introduced exogenous bacterial strains into the rumen in an attempt to improve fermentation processes or counteract ruminal digestive disorders. Some attempts have been successful in the establishment of the new strain although others have failed. To a large extent, particular conditions necessary to the establishment of a new strain are not yet fully understood. In the present study, Ruminococcus flavefaciens NJ (NJ), isolated from the rumen of a wild moose, was introduced into the rumen of six ruminally fistulated non-lactating dairy cows receiving either a high concentrate or a high forage diet and supplemented on a daily basis with a probiotic mixture. In a second experiment, NJ and the probiotic mixture were given to young calves of 21 to 35 d of age. During repeated dosing, NJ modified the abundance of other cellulolytic bacterial populations compared with periods with no dosing. NJ also improved in sacco digestibility of timothy hay with the high concentrate diet. NJ declined rapidly in the rumen from 106 cells mL-1 after dosing to 102 cells mL-1, 24 h following dosing. The persistence of NJ increased with weeks of dosing in cows or when introduced in the rumen of young calves (105 cells mL-1 after 48 h and 102 cells mL-1 after 7 d). The presence of probiotics or a change in the concentrate to forage ratio in the diet did not succeed in establishing the new strain in the rumen. Key words: Ruminococcus flavefaciens NJ, probiotics, rumen fermentation, cellulolytic populations, in sacco digestibility, non-lactating dairy cows

Sheep rumen digestion and transmission of weedy Malva parviflora seeds

The effect of sheep digestion and mastication on Malva parviflora L. seed transmission, viability and germination was investigated. Mature M. parviflora seeds were subjected to 2 seed treatments: ‘scarified’, where the hard seed coat was manually cut to allow imbibition, and ‘unscarified’, where the hard seed coat was not cut. Seeds were placed directly into the rumen of fistulated sheep and removed at 0, 12, 24, 36 and 48 h of rumen digestion. After 12 h of in sacco exposure to digestion in the rumen, the germination of seeds that were initially scarified dropped from 99.2 to 1.4% and longer exposure periods produced no germinable seeds. In contrast, seeds that were unscarified when placed in the rumen produced over 92% germination regardless of in sacco digestion time, although manual scarification after retrieval was essential to elicit germination. In a second experiment, unscarified seeds (29 000) were fed in a single meal to fistulated sheep and feces were collected at regular intervals between 6 and 120 h after feeding. Fecal subsamples were taken to determine number of seeds excreted, seed germination on agar and seed germination from feces. Major seed excretion in the feces commenced after 12 h and continued until 144 h, with peaks between 36 and 72 h after consumption. Although mastication and gut passage killed the majority of unscarified seeds, about 20% were recovered intact and over 90% of these recovered seeds were viable and could, thus, potentially form an extensive seed bank. A few excreted seeds (1%) were able to germinate directly from feces, which increased to a maximum of 10% after subsequent dry summer storage (3 months). Through information gained in this study, there is a potential to utilise livestock in an integrated weed management program for the control of M. parviflora, provided additional measures of weed control are in place such as holding periods (&gt;7 days) for movement of livestock from weed infested areas.

Effect of Microwave Treatment on Chemical Composition and In sacco Digestibility of Wheat Straw in Yak Cow

Wheat straw was treated with microwave for 4 min and 8 min at a power of 750 W and frequency of 2,450 MHz. Chemical compositions of untreated, 4 min treated and 8 min treated Straws were analyzed and in sacco degradabilities of all these straws in yak rumens were measured. Microwave treatment didn't significantly (p > 0.05) affect the chemical composition of the straw. In sacco dry matter (DM) degradability of the straw after 18 h incubation in rumen was significantly (p 0.05) affected by microwave treatment. In sacco organic matter (OM) degradability of the straw was increased (p < 0.01) by around 20% for both the 4 min and 8 min microwave treatment, that of acid detergent fibre (ADF) was increased (p < 0.01) by 61.6% and 62.8%, and that of ash free ADF was enhanced by 72.1% and 69.6% for the 4 min and 8 min microwave treatment respectively. No significant difference was observed between the 4 min and 8 min microwave treatment on the degradability of DM, OM, CP, ADF and ash-free ADF of the straw.

Composition of condensed tannins from Calliandra calothyrsus and correlation with in sacco digestibility

Calliandra calothyrsus accessions differ widely in digestibility for livestock. It is not clear, however, whether this is related to differences in condensed tannin levels or to other factors. Condensed tannins (CT) were extracted from seven different accessions of C. calothyrsus, and were examined for protein binding, pH stability of protein tannin complexes and CT composition. The compositional data was correlated with dry matter and nitrogen digestibility in sacco. Calliandra CT formed insoluble complexes with casein, bovine serum albumin and rubisco protein in an approximate ratio of 1:2 (w/w, tannin:protein) and the insoluble complexes were relatively stable to pH within the range of pH from 2.5 to 8.0. Polymeric proanthocyanidins were associated with both insoluble and soluble protein fractions, but the flavonols and flavonol glycosides were only associated with the soluble fraction. Total CT from each accession was fractionated by SepPak C18 reverse phase column chromatography into phenolic acids, monomers, oligomers/flavonols and polymeric proanthocyanidin fractions and quantified as total phenolics. There was wide variation between fractions across the seven accessions. Fractionation data were correlated with dry matter and nitrogen digestibility in sacco for each accession. Correlations were strongly negative (−0.799) and strongly positive (+0.800) for oligomers/flavonols and polymeric proanthocyanidins, respectively. Fractions were analysed by HPLC and by acid degradation in the presence and absence of phloroglucinol; the data show that across seven different accessions of calliandra, the composition of condensed tannins differed widely. The data suggest that for calliandra, total phenolics is not a good predictor of digestibility, and that the concentration of oligomers/flavonols or the ratio of polymers to oligomers may be more indicative.

VARIATION IN NUTRITIVE VALUE BETWEEN FOUR HALOPHYTIC SHRUB SPECIES COLLECTED FROM FIVE SALINE ENVIRONMENTS

Three species of saltbush (A. amnicola, A. nummularia and A. undulata) and bluebush were collected from five sites in Western Australia (Dalwallinu, Meckering, Tammin, Katanning and Lake Grace) that had previously been established to saline pastures, although not all species were present at all 5 sites. Five individual plants of each species were randomly selected from within a 2500 m 2 area for the collection of leaf material. The leaf material was analysed for the following attributes; in vitro and in sacco digestibility of the organic matter in the dry matter (DOMD), ash and insoluble ash content, acid detergent fibre (ADF), neutral detergent fibre (NDF) and nitrogen (N) content. In vitro digestibility was determined using a modified Klein and Baker (1993) pepsin-cellulase procedure. These in vitro measurements were not calibrated for in vivo digestibility due to a lack of reliable calibration standards from diets containing high salt. Since not all species were present at each site, an analysis of variance using unbalanced treatments was used. Table 1 provides data on the nutritional attributes of the 4 halophytes. Bluebush tended to accumulate more ash and insoluble ash than the 3 saltbush species. Atriplex nummularia contained higher concentrations of N and was more digestible than the other species. However, A. amnicola and A. undulata had higher ADF and NDF concentrations. Considering the standard deviations, it was apparent that there was variability within the 4 species of halophytes, with A. amnicola and A. undulata showing greatest differences in both in vitro and in sacco digestibility, and ash content. However, the reasons for such differences could not be determined. Table 1. Nutritional attributes (means (% of DM) ± s.d.) of 4 halophytes (see the text for details).

The nutritive value of Rhodes grass (Chloris gayana) when treated with CaO, NaOH or a microbial inoculant and offered to dairy heifers as big-bale silage

AbstractA series of laboratory and animal studies examined the use of chemical and biological agents to enhance the digestibility of Rhodes grass (grass) cut at 60 (young) and 100 (mature) days of regrowth and ensiled as big round bales. The treatments included an untreated control (C), a microbial inoculant (I), NaOH, CaO and NaOH plus inoculant (NaOH + I). Inoculant was grown anaerobically, using a starter culture of rumen fluid from cattle given Rhodes grass. Treatments C, I, NaOH, NaOH + I, were offered separately to twelve dairy heifers, in a 3✕4 randomized complete block design, repeated twice for each grass silage. C and I had substantial mould growth, compared with no visible mould in NaOH or NaOH + I. CaO treatment was effective in preventing mould growth, but had little effect on the chemical composition and in sacco digestibility of mature grass silage. NaOH reduced NDF content and increased in sacco digestibility (P&lt; 0·05) but not the in vivo digestibility (P&gt; 0·05) of both mature- and young-grass silage. The effects of other treatments on nutritive value were non-significant at both stages of maturity. NaOH increased the intake of mature-grass silage by 24-26% (P&lt; 0·05), but had little effect on the intake of young-grass silage (P&gt; 0·05). Treatment I consistently reduced grass silage intake (P&lt; 0·05) for young-grass silage. The findings of these studies show that treating mature Rhodes grass with NaOH will improve its nutritive value and reduce mould growth in conserved herbage. However none of the treatments in this study had any consistently positive effects on the in vivo nutritive value or storage quality of young-grass silage.