In Vitro Organic Matter Digestibility Values Research Articles

The effect of the addition of fermented natural lactic acid bacterial liquid and some lactic acid bacterial inoculants on alfalfa silage quality, in vitro digestibility and gas production

This study was conducted to evaluate the effect of adding fermented natural lactic acid bacteria (PFJ) obtained from different sources and some lactic acid bacteria inoculants to alfalfa (Medicago sativa L.) silage on fermentation, in vitro organic matter digestibility (IVOMD) and in vitro gas production. In the study, (i) pure alfalfa plant constituted the control group, whereas (ii) 2% molasses added group (iii) PFJ (3% molasses) prepared from alfalfa + 2% molasses to alfalfa plant, (iv) PFJ (3% molasses) prepared from meadow grass + 2% molasses alfalfa. plant, (v) PFJ (3% Molasses) prepared from maize + 2% molasses to alfalfa plant, (vi) homofermentative added group + 2% molasses to alfalfa plant, (vii) heterofermentative group + 2% molasses to alfalfa plant, added groups formed the trial groups. Homofermentative and heterofermentative LAB inoculants were added to alfalfa plant at the level of 108 cfu/kg. When the DM, CA, ADF, NDF, IVOMD, ME and CH4 values of the prepared silages were examined, the differences between the groups were found to be statistically significant. When the fermentation characteristics (pH, NH3-N, CO2, LA, AA, BA, mold) of the silages prepared by adding PFJ and some LAB inoculants to alfalfa plant, the differences between groups were found to be statistically significant. When examined in terms of all parameters, it was determined that the addition of PFJ (3% molasses) prepared from meadow grass + 2% molasses to alfalfa plant had positive effects on silage quality, fermentation characteristics and in vitro organic matter digestion.

Biovalorization of Grape Stalks as Animal Feed by Solid State Fermentation Using White-Rot Fungi

This work aimed to evaluate the potential of three fungi strains, Lentinula edodes, Pleurotus eryngii, and Pleurotus citrinopileatus, to degrade lignin and enhance the nutritive value of grape stalks (GS). The GS was inoculated with the fungi and incubated under solid-state fermentation at 28 °C and 85% relative humidity for 7, 14, 21, 28, 35, and 42 days, in an incubation chamber. The influence of the treatments was evaluated by analyzing the potential modifications in the chemical composition, in vitro organic matter digestibility (IVOMD) and enzymatic kinetics. An increase (p < 0.001) in the crude protein content was observed in the GS treated with L. edodes and P. citrinopileatus at 42 days of incubation (50 and 75%, respectively). The treatment performed with L. edodes decreased (p < 0.001) lignin content by 52%, and led to higher (p < 0.001) IVOMD values at 42 days of incubation. By contrast, P. eryngii did not affect lignin content and IVOMD. A higher activity of all enzymes was also detected for the treatment with L. edodes. Results indicated that L. edodes has a great potential to enhance the nutritive value of GS as an animal feed, due to its lignin degradation selectivity.

The Effect of Zinc-Proteinate Supplementation on the In Vitro Digestibility and Ruminal Fermentation in Goat

This study aimed primarily to investigate the effect of Zn-Proteinate (Zn-Prot) supplementation on in vitro rumen digestibility and rumen fermentation. This research used a completely randomized design with four treatments and four replicates. The experimental treatment was the supplementation of various levels of Zn-Prot (0; 12.5 ppm; 25 ppm, and 37.5 ppm) on a dry matter basis. Parameters determined were in vitro dry matter digestibility (IVDMD), in vitro organic matter digestibility (IVOMD), partial volatile fatty acid (VFA) (acetate, propionate, and butyrate), A/P ratio, CH4, and the efficiency of the conversion hexose to VFA. Data were analyzed using ANOVA. The results showed that goats fed with a diet supplemented with 25 ppm Zn-Prot had the highest IVDMD and IVOMD values. There was no significant effect on the VFA and CH4 concentrations, A/P ratio, and the efficiency of the hexose-VFA conversion within treatment groups. In conclusion, supplementing 25 ppm of Zn-Prot into the diet of dairy goat increase the dry matter and organic matter digestibility.

Forage yield and quality response of annual ryegrass (Lolium multiflorum) to different water and nitrogen levels

Water and nitrogen shortages in annual ryegrass (Lolium multiflorum) production can be improved by using proper irrigation and nitrogen scheduling methods. The aim of this research was to analyse the effect of water and nitrogen application on dry matter production and forage quality of annual ryegrass. Treatments consisted of three irrigation levels, scheduling application to field capacity once every two weeks (W1), once a week (W2) or twice a week (W3), and three nitrogen (N) levels, top-dressing after each harvest at a rate of 0 (N1), 30 (N2) or 60 (N3) kg N h−1 cycle−1. Yield increased as a function of the amount of water and nitrogen fertiliser applied. The dry matter (DM) content, in vitro organic matter digestibility (IVOMD), crude protein (CP) and metabolisable energy (ME) were higher in the treatments being irrigated once every two weeks. These results conclude that higher irrigation coupled with high N application significantly improved the dry matter yield, while water stress, to some extent, did improve the quality of the pasture by increasing the DM content, IVOMD, CP and ME values.

Taze ve Dondurulmuş Fermente Edilmiş Sıvının (PFJ) Yonca Silajının Fermentasyon Kalitesi Üzerine Etkisi

Summary This study was carried out to examine the possible effect of fresh and frozen pre-fermented juice (PFJ) on the fermentation quality, nutritive value and in vitro gas production parameters of alfalfa (Medicago sativa L.) silage. Barley (B), wheat (W) and grass herbage (G) were used to prepare the PFJs. Both fresh (PFJ-B, PFJ-W and PFJ-G) and frozen (PFJ-B F , PFJ-W F and PFJ-G F ) PFJs were investigated. Frozen PFJs were prepared by freezing fresh PFJs at -22 o C with 20% glycerol (v/v). Treatments of alfalfa silage consist of (1) control (untreated alfalfa silage); (2) silage treated with PFJ-B; (3) silage treated with PFJ-W; (4) silage treated with PFJ-G; (5) silage treated with PFJ-B F ; (6) silage treated with PFJ-W F and (7) silage treated with PFJ-G F . Each treatment had five replicate glass jars and replicates were ensiled in 1.0 L jars. Silages treated with fresh and frozen PFJs, regardless of plant material, had better fermentation quality than the control silage in terms of lower pH, butyric acid (BA) and ammonia nitrogen (NH 3 -N) concentrations. Additionally, treated silages with fresh PFJs had higher lactic acid (LA) concentration (P<0.05) and in vitro organic matter digestibility (IVOMD), metabolizable energy (ME) content and gas production values (P<0.05) than control silage. According to results of this study, PFJ treatments increased the nutritive value, fermentation quality, IVOMD, ME content and gas production values of alfalfa silage.

Influence of individual and mixed extracts of two tree species on in vitro gas production kinetics of a high concentrate diet fed to growing lambs

This study was conducted to investigate effects of different doses of Leucaena leucocephala (LL) and Salix babylonica (SB) extracts, rich in secondary metabolites, and their mixture (LLSB, 1:1, v/v) on in vitro gas production and some ruminal fermentation patterns such as truly degraded substrate (TDS), short chain fatty acids (SCFA), and microbial protein production (MP) of a high concentrate diet (HCD) fed to growing lambs. The HCD contained (g/kg DM): crude protein (CP), 208; ether extract (EE), 12; neutral detergent fibre (NDFom), 364; acid detergent fibre (aADFom), 41. Plant extracts were prepared at 1 g DM/8 ml of solvent mixture (methanol:ethanol:water, 1:1:8) and added at levels of 0, 0.6, 1.2 and 1.8 ml/g DM. Rumen liquor was collected from 8 growing lambs (Katahdin × Pelibuey, LW 24 ± 0.3 kg) fed the same HCD. In vitro gas production (GP) was recorded at 2, 4, 6, 8, 10, 12, 24, 48 and 72 h of incubation. After 72 h, the incubation was stopped and the inoculants pH was determined and filtered to determine TDS. Ruminal fermentation parameters such as 24 h partitioning factor (PF 24), gas yield (GY 24), in vitro organic matter digestibility (IVOMD), metabolizable energy (ME), SCFA, and MP were also estimated. Tree species × extract level interaction ( P < 0.05) only occurred for gas production at 24 (GP 24), 48 (GP 48) and 72 h (GP 72) of incubation, but there were no interactions before 24 h of incubation. Relative to control, addition of extracts increased ( P < 0.05) gas volume GP 24, GP 48 and GP 72, except LLSB extract which had lower ( P < 0.05) values during the first 48 h of incubation versus control ( i.e., 0 ml/g DM). There was no significant impact of extracts on gas production parameters ( i.e., b; asymptotic gas production, c; rate of gas production and L; discrete lag time prior to gas production), while the L tended to decrease ( P = 0.073) with increasing extract dose only in LL and SB extracts. Addition of either dose of supplemental LL and SB extracts increased ( P < 0.05) gas production and this increase was higher ( P < 0.05) for 1.2 ml and 1.8 ml than 0.6 ml extract/g DM for GP 24, GP 48 and GP 72. In general, gas productions were higher ( P < 0.05) in SB than LL extract. There were no interaction in final ruminal pH, PF 24 and GY 24, while some fermentation parameters ( i.e., TDS, IVOMD, ME, SCFA, and MP) were higher ( P < 0.05) in LL and SB extract doses versus control. The highest two extract doses ( i.e., 1.2 and 1.8 ml/g DM) increased ( P < 0.05) TDS, IVOMD, ME, SCFA and MP values versus 0.6 ml/g DM. The SB extract also had higher positive impacts ( P < 0.05) on rumen fermentation parameters versus LL extract. It is suggested that the individual extracts of LL and SB, but not the mixture, could positively modify rumen gas production and fermentation, which may improve nutrient utilization in growing lambs.

The effects of strategic nitrogen fertiliser application during the cool season on perennial ryegrass-white clover pastures in the Western Cape Province 4. Selected nutritive characteristics and mineral content

The influence of a single application of fertiliser N (0, 50, 100 and 150 kg N ha−1) applied in either autumn, early winter, late winter, early spring or late spring on selected nutritive and mineral parameters of a perennial ryegrass-white clover pasture was investigated over a three-year period. Responses were measured over one regrowth cycle five weeks after the application of N treatments. A sample of the plant material harvested was separated into grass and clover fractions. Dry matter (DM), crude protein (CP), in vitro organic matter digestibility (IVOMD), phosphorus (P) and calcium (Ca) content were determined for each sample. Winter applications of fertiliser N, in combination with the higher N rates, resulted in higher ryegrass CP contents. Clover CP content was decreased (P=0.05) with spring (early and late) applications, but fertiliser N rate did not appear to affect clover CP content. The highest IVOMD values for both ryegrass and clover were recorded in winter. Increased fertiliser N rate resulted in lower DM contents with the lowest DM produced during winter, while the highest DM contents were produced where no fertiliser N was applied in spring. P content was significantly influenced by season of application and fertiliser N rate in ryegrass and only by season of application in clover. The highest mineral concentrations were found in winter. The rate and season of fertiliser N application as used in this study did not negatively affect pasture mineral content and quality, but care must be taken to protect the grazing animal from the potential negative effects of high forage N contents on animal health.

Nutritive value of some agricultural wastes as affected by relatively low gamma irradiation levels and chemical treatments

An experiment was carried out to study the changes in the values of in vitro organic matter digestibility (IVOMD) and metabolizable energy (ME) of wheat straw, sunflower seed shell, olive cake wood, date palm seeds and peanut shell after irradiation with various levels of gamma radiation (0, 20, 40, 60 kGy; kiloGray) or after spraying with different amounts of hydrobromic acid (HBr; 47%) and sodium hydroxide (NaOH): 0, 3, 6 ml HBr and 3, 6 g NaOH in 25 ml water/100 g DM. The results indicated that chemical treatments increased the IVOMD and ME values significantly for all samples treated except the date palm seeds. There was no significant effect of irradiation on IVOMD and ME. Combined treatments of irradiation and HBr or NaOH were also found to be ineffective in increasing the IVOMD and ME values.

In vitro digestibility using caecal liquor of diets containing poor quality roughages and green forages fed to domesticated ostriches ( Struthio camelus var. domesticus)

The objective of this study was to compare in vitro organic matter digestibility (IVOMD) of ostrich diets using the normal (NTT) and reverse (RTT) modified Tilley and Terry methods of in vitro digestion. The IVOMD values of green forages were determined using the RTT method only. Four ostrich diets and four green forages were digested in vitro using caecal liquor collected from ostriches slaughtered at the Norton Commercial ostrich producers (Copro) abattoir. The diets included a control diet of a concentrate and legume hay, silverleaf desmodium uncinatum (CN), and the three others consisting of a concentrate with either veld hay (VH), Katambora Rhodes grass hay (RG) or maize stover (MS). Lucerne (LU), Midmar Rye grass (MRG), Russian Comfrey (RC) and Kenyan White clover (KWC) were the green forages used. The forages were grown under the recommended management levels and were cut before flowering. There was no interaction ( P>0.05) between diet and method of digestion. The RTT gave higher ( P<0.01) IVOMD than the NTT method. However, both methods showed a similar trend in the digestion of the diets. The MS and RG diets had similar and greater ( P<0.05) IVOMD than the control and veld hay diets. The amounts of organic matter (OM) digested differed ( P<0.01) with either diet or forage type. Kenyan White clover and MRG had similar and greater ( P<0.05) IVOMD than LU and RC, which were not different ( P>0.05). The values of IVOMD in dry matter for the forages were: MRG > KWC > LU > RC, and all the differences were significant ( P<0.05). The study showed that the NTT method needs to be modified to suit hind gut fermenters and IVOMD can, therefore, be used to rank the nutritive value of ostrich feeds.

An assessment of the nutritive value of browsed plants in Makurdi, Nigeria

Twenty-five plant species were identified as useful cattle feedstuff during peak dry season in Makurdi, Benue State. Leguminous species accounted for over 48% of the browse. The browsed plants were classified on the basis of frequency of browsing into those heavily, moderately or occasionally browsed by cattle and analysed for chemical constituents. The samples showed high nutritive potentials with crude protein values of 14% in 92% of the samples. The lowest crude protein value was in Mucuna poggei (10.9%) while the highest was in Lonchocarpus cyanescens (31.7%). The heavily browsed group was superior to the other groups in protein content (21.4%) and in calculated in vitro organic matter digestibility (IVOMD) (50.6%). The IVOMD values ranged from 32.7 to 52.4%. The relationship between IVOMD and crude protein was negative and non-significant (r = - 0.22). Generally, the mineral content was high with the heavily browsed species containing higher calcium (1.52%) and phosphorus levels (0.35%) than either the moderately (1.22% Ca and 0.22% P) or the occasionally (1.15% Ca and 0.32% P) browsed groups. The vital role of browse as a feedstuff for cattle especially in the dry season and the need to propagate them in plantations in the Middle Belt zone were emphasized. [Niger Agric. J. 33 (2002): 128-135]

Morphological development and forage quality changes in crimson clover (Trifolium incarnatum L.)

The development of efficient forage management and utilization is facilitated by a knowledge of the changes in nutritive value and patterns of dry matter (DM) distribution within plants. The objectives of this experiment were to determine the patterns of DM accumulation and the change in nutritive value during maturation of crimson clover (Trifolium incarnatum L.), a cool‐season annual forage legume adapted to mild winter areas and acid soils. Crimson clover was established on a Dystric Eurocrept soil with pH 5·4 in Galicia, north‐western Spain, during three consecutive years (1990–92). Shoot samples were taken at approximately biweekly intervals in the spring and summer after autumn sowing, and were separated into stems, leaves and seed pods. DM accumulation, crude protein (CP) and acid‐detergent fibre (ADF) concentrations and in vitro organic matter digestibility (IVOMD) were determined for each plant part at each stage. Average annual DM production at initial flowering was 4·2 t ha–1, whereas the CP and ADF concentrations and IVOMD values were 134 g kg–1 DM, 302 g kg–1 DM and 0·720 respectively. The nutritive value declined with age, coinciding with a reduction in leaf:stem ratio (from 0·53 at the vegetative stage to 0·13 at the ripe seed stage). This decline was more rapid than that reported for other legumes, possibly because of the low leaf:stem ratio of crimson clover. However, as it is used in the Atlantic coastal areas of north‐western Spain, where it is harvested around initial flowering, it can provide forage of good quality.

The effects of inorganic and organic Zn, Cu and Mo supplementation to the in vitro digestibility of grass

The effects of inorganic and organic Zn, Cu and Mo supplementation to the in vitro digestibility of Elephant grass were studied in this trial. The in vitro trial used the TILLEY dan TERRY method modified by VAN SOEST with the incubation of the grass for 48 hours in sheep rumen liquor medium. Mineral added as fonn of organic and inorganic. The treatment of mineral inorganic supplementations were by adding single e1emen Cu, Zn and Mo and its combination. Mineral added was Zn (as chloride and sulphate salts) 5 ppm, Cu (sulphate salt) 0,1 ppm dan Mo (molybdate salt) 5 ppm, with 4 replicates. Meanwhile the organic minerals added were in the proteinate fonns. Parameter measured were in vitro dry matter digestibility (IVDMD), in vitro organic matter digestibility (IVOMD), pH, VF A total and NH3. Statistical analysis was done by using Complete Split splitsplot design. The supplementation increased pH value, VFA total, IVDMD and IVOMD value (P<0,05) and decreased NH3 value. The highest IVDMD and IVOMD values obtained at the mixture supplementation of mineral Zn (as Zn S04), Cu and Mo, from 58,31 became 69.73% and 52.22 became 62.55% respectively for IVDMD and NOMD. pH value increased from 6.48 to 7.05 and ammonia content decreased from 1,17 to 0,14%. The organic mineral supplementation, en-proteinate dan Zn-proteinate showed that the adding of Zn, Zn and Mo, Zn and Cu also the combination of Zn, Cu and Mo, resulted in IVDMD values as 70.29; 69.97, 64.12 and 63.93%. Further more IVDMD value at the supplementation of Cu and the combination of Cu and Mo were 65.08 and 60,49%. It can be concluded that the supplementation of minerals in the form of inorganic or organic could improve the IVDMD values Key words : Three element, in vitro digestibility, sheep

Forage value of Mediterranean deciduous woody fodder species and its implication to management of silvo-pastoral systems for goats

Forage value of 10 deciduous woody fodder species during six stages of maturity as well as their acceptance by goats in July and August were studied in Macedonia, northern Greece. The fodder species studies wereAmorpha fruticosa L.,Carpinus orientalis Mill.,Colutea arborescens L.,Corylus avellana L.,Fraxinus ornus L.,Ostrya carpinifolia Scop.,Pyrus amygdaliformis Vill.,Quercus pubescens Willd.,Quercus sessiliflora Salich, andRobinia pseudoacacia L. with two accessions, common and spineless. All these species are integral components of the mediterranean silvo-pastoral systems. Monthly forage samples were collected throughout their growing period (May to November), which coincides with the long dry summer when herbaceous plants are dormant, and analyzed for crude protein content, neutral detergent fiber (NDF), lignin and in vitro organic matter digestibility (IVOMD). Comparing the leguminous species (Robinia pseudoacacia, Amorpha fruticosa, Colutea arborescens) with the remaining species, the leguminous one had on average a higher (P≤0.05) content of crude protein (21.1%, 21.0% and 17.1% vs. 10.5–13.3%, respectively) and higher (P≤0.05) IVOMD values (58.4%, 56.0% and 60.0% vs. 47.3–52.8, respectively). Moreover, the leguminous species were among species with lower NDF (42.3%, 45.0% and 35.2% vs. 36.0–48.9%, respectively) and lignin content (7.1%, 8.3% and 9.1% vs. 7.6–10.9%). All species showed a significant increase in crude protein when new leaves appeared (May). Most of the fodder species had digestibilities in the higher range (>55% IVOMD) and low NDF content (<53.5%) during the growing season (first five stages). Lignin contents ranged from 5.9% (A. fruticosa, May) to 16.0% (O. carpinifolia, Nov.).Robinia pseudoacacia had the highest relative acceptance index whileAmorpha fruticosa, Colutea arborescens andCorylus avellana the lowest. It is concluded that deciduous woody fodder species may play a significant role as sources of nutrients in the mediterranean silvo-pastoral systems during the summer period of seasonal nutritional shortage.

Pine Needle Effects on in vivo and in vitro Digestibility of Crested Wheatgrass

In vitro and in vivo digestion trials with lambs were conducted to determine effects of ponderosa pine needles (PN; Pinus ponderosa Laws.) on digestibility of crested wheatgrass (CW; Agropyron desertorum [Link] Schultes) hay. Pine needles contained shikimic acid (15-28 mg/g) and several monomeric phenolics (p-hydroxy benzoid acid, caffeic acid, p-coumaric acid, ferulic acid) and flavonoids. Tannin concentration exceeded assay limits (>10%) and terpenes were not found, probably due to the drying procedure. In the in vitro trial, needles were mixed with CW in 10% increments from 0% to 100%. In the in vivo trial, PN were fed to lambs as follows: (1) 0%, (2) 12.5%, (3) 25%, and (4) 50%, with the remainder of the diet as CW. In vitro organic matter digestibility (IVOMD) was regressed on level of PN in the substrate. As the proportion of PN increased, IVOMD declined cubicly (P<0.01). The IVOMD values ranged from 54% for 100% CW to 24% for 100% PN. In vivo digestibility of organic matter, neutral detergent fiber and acid detergent fiber declined linearly (P<0.01) as PN were increased from 0% to 50% of the diet. Apparent crude protein digestibility and N retention by lambs declined cubicly (P = 0.02 and P<0.01, respectively) and urinary N increased cubicly (P<0.01) as dietary PN increased from 0% to 50%. We concluded that PN reduce in vitro and in vivo nutrient digestibility, reduced N retention by lambs, and effects were detectable even at low levels.

Changes in the nutritional composition of cassava ( Manihot esculenta Crantz) leaves during maturity

The nutritional composition, in vitro organic matter digestibility (IVOMD) and anti-nutritive properties of cassava ( Manihot esculenta Crantz) leaves were investigated at three stages of leaf maturity (very young, young and mature leaves). The crude protein and carbohydrate contents decreased with maturity, whereas all other proximal and fibre components increased. The mineral profile showed cassava leaves to be good sources of most minerals, particularly of calcium and trace minerals. The P and Na contents, however, were low. The values for K, Mg, P, Zn and Mn decreased with leaf maturity, while those for Ca, Na and Fe increased. Cassava leaves were found to be rich in all essential amino acids, except methionine and phenylalanine. As the leaves matured, the tendency was for the amino acid concentrations to decrease. Only glutamic acid, proline and glycine contents increased, while those of valine and phenylalanine were unaffected. The levels of phytic acid increased with leaf ageing, while tannin and hydrocyanic acid contents decreased. The nutritional significance of these anti-nutritive factors is discussed. The IVOMD values indicate the potential value of cassava leaves as a ruminant feed.

Effect of variety and nitrogen application on the nutritive value of rice straw and stubble

A field study was conducted to compare the nutritive value of straw and stubble from six varieties of rice grown under two levels of nitrogenous fertilizer application. The nutritive values of stubble harvested directly after straw harvest (stubble 1) and that allowed to regrow for two weeks (stubble 2) were also studied. The assessments were based on crude protein content (CP) and in vitro organic matter digestibility (IVOMD). Level of fertilizer, variety and part of the plant (straw/stubble) caused significant changes (P < 0·05) in the CP values. Also, the variety × plant-part interaction was significant (P < 0·05). The mean CP content for straw was significantly lower than for stubble (5·3 and 5·5), and the values for the different varieties ranged from 4·9% to 5·9%. Variety and part of the plant showed significant (P < 0·0001) effects on IVOMD, whereas effects due to level of fertilizer were not significant. The overall IVOMD values show more relevant differences than the CP values, straw being significantly higher than the stubble (40·2 and 35·0%). Within the six varieties, the IVOMD of straws and stubbles ranged from 32% to 47%, and 30% to 43%, respectively. Depending on the variety, the increase in IVOMD between stubble 1 and stubble 2 could range from 3 to 23 digestibility units.

A laboratory assessment of various treatment conditions affecting the ammoniation of wheat straw by urea. 1. The effect of temperature, moisture level and treatment period

The effect of temperature, moisture level and treatment period on the ammoniation of wheat straw by 75 9 urea per kg wheat straw was investigated in a 4 x 2 x 6 factorial experiment. Independent variables included temperatures of 4; 14; 24 and 35°C, moisture levels of 250 and 375 g/kg wheat straw and treatment periods of 0; 1; 2; 4; 6 and 8 weeks. Dependent variables investigated were total nitrogen content, urea content, free ammonia nitrogen content and in vitro organic matter digestibility (IVOMD). Temperature, moisture level and treatment period significantly (P ~ 0,01) affected ammonia release from urea. The efficiency of ammoniation was accordingly affected. Slow ammonia release at 4 °C (at both moisture levels) and at 14°C (only at the lower moisture level) resulted in lesser improvements in IVOMD after a treatment period of eight weeks. Ammoniation was accelerated at higher temperatures, particularly at the higher moisture level. Comparable IVOMD values were obtained after a treatment period of one to two weeks at 35°C and approximately six weeks at 24 °C. Less ammonia was released from urea at 35°C and the moisture level of 375 g/kg, possibly owing to a decrease in urease activity at this temperature. Significant (P ~ 0,01) temperature x treatment period and moisture level x treatment period interactions were obtained, indicating that the slow reaction at lower temperatures and at lower moisture levels can partly be compensated for by a longer treatment period. S. Afr. J. Anim. Sci. 1984, 14: 55 58

Utilization of piggery waste II. The chemical composition and in vitro organic matter digestibility of fractions of pig faeces separated by sieving and by centrifuging

Samples of pig faeces with an in vitro organic matter digestibility (IVOMD) of 31.0% were fractionated by wet sieving through four sieves of mesh sizes 2.34, 1.19, 0.11 and 0.05 mm, and by centrifuging with a force of 2,500 g for 20 min. The fraction passing through the smallest sieve (calculated by difference) represented 35% of the dry matter and had appreciably higher concentrations of nitrogen, true protein, ether extract, ash and copper, and lower concentrations of gross energy, neutral detergent fibre, acid detergent fibre and lignin than the other sieved fractions. However, the IVOMD values were similar for all five fractions. Centrifuging produced three distinct fractions: the supernatant, a layer of ‘fine slimy particles’, and ’coarse fibrous particles’. The supernatant represented an insignificant proportion of the faecal dry matter. The fine slimy particles had higher concentrations of nitrogen, true protein, ether extract, ash and copper and lower concentrations of fibre components than the coarse fibrous particles. The IVOMD values of the fine and coarse fractions were 42.6 and 30.2%, respectively, but because the fine slimy particles accounted for only 10% of the faecal dry matter the separation was considered to be of no practical importance. It was concluded that fractionation of pig faeces by these methods, and without any other processing, did not provide a means of achieving improved utilization by microbial digestion.

Utilization of piggery waste I. The chemical composition and in vitro organic matter digestibility of pig faeces from commercial piggeries in south-eastern Australia

Samples of faeces from 24 commercial piggeries in south-eastern Australia were collected and analysed for nitrogen, gross energy, ether extract, total ash, residual ash, crude fibre, neutral detergent fibre, acid detergent fibre, lignin, cellulose, hemicellulose, calcium, phosphorus, sodium, potassium, magnesium, copper, zinc, iron, cadmium, lead and arsenic. In vitro organic matter digestibility (IVOMD) values were also determined. There was wide variability in the concentration of all constituents; IVOMD values ranged from 23 to 69%. Regression analysis implicated fibre components and some minerals as the major factors affecting IVOMD. The data emphasize the need to take into account the chemical characteristics of the waste in assessing its potential for utilization.