scholarly journals Rumen bacterial and protozoal populations in cattle being relocated in tropical Queensland

1998 ◽  
Vol 49 (7) ◽  
pp. 1153 ◽  
Author(s):  
A. V. Klieve ◽  
R. G. Holroyd ◽  
A. F. Turner ◽  
J. A. Lindsay
Keyword(s):  
Population Density ◽  
Growth Rates ◽  
Rumen Fluid ◽  
Soluble Sugar ◽  
Sampling Period ◽  
Microbial Populations ◽  
Wet Season ◽  
Population Composition ◽  
Heteropogon Contortus ◽  
Ciliate Protozoa

Rumen microbial populations were measured in Brahman-cross steers that were relocated from spear grass (Heteropogon contortus) dominant pastures in northern Queensland to buffel grass (Cenchrus ciliasis) dominant pastures in central Queensland, to assess whether aspects of rumen function may contribute to the sometimes reported depressed growth rates following relocation. Nine genera of ciliate protozoa (Isotricha, Dasytricha, Entodinia, Epidinium, Diplodinium, Ostracodinium, Metadinium, Elytroplastron, and Eudiplodinium) were recorded in the rumen fluid of the steers. In most steers all genera were present at any time and the generic mix persisted throughout the 10 months over which the study was conducted. Protozoal population composition fluctuated only slightly over the sampling period. Entodinia were predominant, occupying 50-70% of the population. Population density varied according to season, with the highest density (4-8×105 /mL rumen fluid) occurring in the wet season. Bacterial and protozoal populations were remarkably stable and little affected by relocation. Again, the major impact on population density was the season, with all carbohydrate (soluble sugar, starch, xylan, and cellulose) utilising bacterial subpopulations reaching the greatest density with the onset of the wet season.

scholarly journals Methane formation in faunated and ciliate-free cattle and its relationship with rumen volatile fatty acid proportions

1984 ◽  
Vol 52 (2) ◽  
pp. 261-275 ◽  
Author(s):  
F. G. Whitelaw ◽  
J. Margaret Eadie ◽  
L. A. Bruce ◽  
W. J. Shand
Keyword(s):  
Fatty Acid ◽  
Volatile Fatty Acid ◽  
Rumen Fluid ◽  
Live Weight ◽  
Microbial Populations ◽  
Methane Formation ◽  
Residual Standard Deviation ◽  
Linear Relationships ◽  
Good Agreement ◽  
Ciliate Protozoa

1. Twelve steers fitted with rumen cannulas were used in three separate experiments to investigate the effects of the presence or absence of rumen ciliate protozoa on methane production. The diet consisted of 850 g barley and 150 g protein supplement/kg, and was given in three feeds daily at a restricted level of 61 g/kg live weight0.75. Animals were defaunated initially by allowingad lib. consumption of this diet and were then maintained ciliate-free by isolation or were faunated by inoculation with a mixed ciliate suspension. Samples of rumen fluid were taken routinely for the assessment of microbial populations and for volatile fatty acid (VFA) analysis and energy and nitrogen balances and digestibility measurements were made at intervals while animals were confined in respiration chambers.2. In each experiment the rumen VFA proportions changed from a high-propionate pattern under ciliate-free conditions to a low-propionate, high-butyrate pattern in the presence of ciliates: differences between treatments were highly significant (P < 0.001). There were also marked differences between treatments in CH, production but a reliable comparison was possible only in Expt 3, in which CH4was significantly higher (P < 0.001) in the presence of a rumen ciliate population. In Expt 3 the increased loss of energy as CH4in the faunated animals amounted to 44 MJ/100 MJ energy intake.3. Stoichiometric estimates of CH4production derived from the observed VFA proportions showed good agreement with CH4production as measured in respiration chambers. On average, the stoichiometric CH4values overestimated CH4production by a factor of 1.08.4. Highly significant linear relationships (P < 0.001) were observed between the molar proportion of each major VFA and the quantity of CH4produced: the proportion of propionic acid was inversely related to CH4and showed the lowest residual standard deviation of all the relationships examined.5. The losses of energy in faeces and urine did not differ between treatments hence the increased loss of energy as CH4in the faunated animals resulted in a significant reduction in the metabolizability of the diet from 0.73 to 0.69 (P < 0.05). No significant differences were detected between treatments in heat production, apparent digestibility coefficients or N balance.6. It is suggested that the rumen ciliates, by modifying the rumen VFA proportions, are directly responsible for the increased CH4production in faunated animals.

Responses in ciliated protozoa and rumen fermentation in sheep supplemented with barley plus virginiamycin

1995 ◽  
Vol 46 (6) ◽  
pp. 1137 ◽  
Author(s):  
TG Nagaraja ◽  
SI Godfrey ◽  
SW Winslow ◽  
JB Rowe
Keyword(s):  
Population Density ◽  
Rumen Fluid ◽  
Rumen Fermentation ◽  
Barley Grain ◽  
Ciliated Protozoa ◽  
Lactate Accumulation ◽  
Treatment Groups ◽  
The Third ◽  
Ciliate Protozoa

An experiment was conducted to determine the changes in the population of ciliate protozoa and the pattern of rumen fermentation in sheep fed a supplement of barley grain on its own or containing virginiamycin. There were three treatment groups with a total of 25 sheep housed in individual pens. All animals were fed chaffed wheaten hay to a maximum of 1.4 kg head-1 day-1. One group received no grain supplement (n = 5), one barley grain (n = 10) and the third barley plus virginiamycin (40 g/t grain; n = 10). The amount of grain was gradually increased over a period of 5 days to a maximum of 700 g of barley or barley plus virginiamycin on day 5. Grain (700 g/head) was then fed twice weekly for a further 18 days. Samples of rumen fluid were taken on days 1, 2, 3, 5*, 6, 9*, 12*, 23* and 24 (* signifies days when 700 g barley was fed). In sheep supplemented with barley the population density of ciliate protozoa was increased (P < 0.01) from day 3 of the 5 day introduction to grain (approximately 170x104 protozoa/mL at day 5), but the increase was not sustained when grain was fed at intervals of 3 or 4 days. In sheep supplemented with barley plus virginiamycin, the population density of ciliate protozoa was increased significantly (P < 0.01) only at days 5 and 6 of the experiment (approximately 100x l04 protozoa/mL at day 5). Sheep supplemented with barley plus virginiamycin at day 5 had a higher concentration of L-lactate (P < 0.05) at 6 and 12 h and propionate (P < 0.05) at 6, 9, 12 and 24 h than sheep supplemented with barley alone. It was concluded that virginiamycin was inhibitory to protozoa during the introduction to grain, and L-lactate accumulation in the rumen of sheep supplemented with barley plus virginiamycin may be a result of altered fermentation associated with reduced numbers of protozoa.

scholarly journals Changing Land Use and Population Density Are Degrading Water Quality in the Lower Mekong Basin

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1948
Author(s):  
Flavia Tromboni ◽  
Thomas E. Dilts ◽  
Sarah E. Null ◽  
Sapana Lohani ◽  
Peng Bun Ngor ◽  
...  
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Population Density ◽  
Local Population ◽  
Reference Conditions ◽  
Mekong River ◽  
Land Use Impacts ◽  
Wet Season ◽  
Mekong Basin ◽  
Lower Mekong Basin

Establishing reference conditions in rivers is important to understand environmental change and protect ecosystem integrity. Ranked third globally for fish biodiversity, the Mekong River has the world’s largest inland fishery providing livelihoods, food security, and protein to the local population. It is therefore of paramount importance to maintain the water quality and biotic integrity of this ecosystem. We analyzed land use impacts on water quality constituents (TSS, TN, TP, DO, NO3−, NH4+, PO43−) in the Lower Mekong Basin. We then used a best-model regression approach with anthropogenic land-use as independent variables and water quality parameters as the dependent variables, to define reference conditions in the absence of human activities (corresponding to the intercept value). From 2000–2017, the population and the percentage of crop, rice, and plantation land cover increased, while there was a decrease in upland forest and flooded forest. Agriculture, urbanization, and population density were associated with decreasing water quality health in the Lower Mekong Basin. In several sites, Thailand and Laos had higher TN, NO3−, and NH4+ concentrations compared to reference conditions, while Cambodia had higher TP values than reference conditions, showing water quality degradation. TSS was higher than reference conditions in the dry season in Cambodia, but was lower than reference values in the wet season in Thailand and Laos. This study shows how deforestation from agriculture conversion and increasing urbanization pressure causes water quality decline in the Lower Mekong Basin, and provides a first characterization of reference water quality conditions for the Lower Mekong River and its tributaries.

Effects of moisture supply in the dry season and subsequent defoliation on persistence of the savanna grasses Themeda triandra, Heteropogon contortus and Panicum maximum

1992 ◽  
Vol 43 (2) ◽  
pp. 241 ◽  
Author(s):  
JJ Mott ◽  
MM Ludlow ◽  
JH Richards ◽  
AD Parsons
Keyword(s):  
Growing Season ◽  
Close Correlation ◽  
Dry Season ◽  
Carbon Gain ◽  
Panicum Maximum ◽  
Wet Season ◽  
Themeda Triandra ◽  
Heteropogon Contortus ◽  
Moisture Conditions ◽  
Sheath Material

The close correlation between grazing-induced mortality and major climatic patterns in Australian savannas, led us to the hypothesis that moisture conditions during the dry, non-growing season could affect sensitivity to grazing in the subsequent growing season. Using three widespread savanna species (Themeda triandra, Heteropogon contortus and Panicum maximum), this hypothesis was tested experimentally and the mechanisms controlling this response examined and quantified. In T. triandra drought during the dry season led to major mortality in defoliated plants in the next growing season. This mortality was caused by a synchrony of tillering at the commencement of the wet season, leaving few buds for replacement once parent tillers were killed by defoliation. T. triandra was also the most sensitive species to defoliation. This sensitivity was due to the poor ability of the plant to maintain positive carbon gain after defoliation. Several factors contributed to this poor ability, including: low total photosynthetic rate, low specific leaf area, and a large proportion of sheath material with poor photosynthetic capacity remaining after cutting. Both H. contortus and P. maximum growing under irrigated and fertilized conditions did not display any effects of previous moisture treatments when defoliated during the next wet season and were much less sensitive to defoliation than T. triandra.

scholarly journals Growth, leaf and stomatal traits of crabwood (Carapa guianensis Aubl.) in central Amazonia

2012 ◽  
Vol 36 (1) ◽  
pp. 07-16 ◽  
Author(s):  
Miguel Angelo Branco Camargo ◽  
Ricardo Antonio Marenco
Keyword(s):  
Growth Rates ◽  
Stomatal Density ◽  
Leaf Gas Exchange ◽  
Carbon Assimilation ◽  
Leaf Traits ◽  
Leaf Thickness ◽  
Diurnal Changes ◽  
Wet Season ◽  
Carapa Guianensis ◽  
Rainfall Seasonality

Crabwood (Carapa guianensis Aubl.) is a fast growing tree species with many uses among Amazonian local communities. The main objective of this study was to assess the effect of seasonal rainfall pattern on growth rates, and seasonal and diurnal changes in leaf gas exchange and leaf water potential (ΨL) in crabwood. To assess the effect of rainfall seasonality on growth and physiological leaf traits an experiment was conducted in Manaus, AM (03º 05' 30" S, 59º 59' 35" S). In this experiment, six 6-m tall plants were used to assess photosynthetic traits and ΨL. In a second experiment the effect of growth irradiance on stomatal density (S D), size (S S) and leaf thickness was assessed in 0.8-m tall saplings. Stomatal conductance (g s) and light-saturated photosynthesis (Amax) were higher in the wet season, and between 09:00 and 15:00 h. However, no effect of rainfall seasonality was found on ΨL and potential photosynthesis (CO2-saturated). ΨL declined from -0.3 MPa early in the morning to -0.75 MPa after midday. It increased in the afternoon but did not reach full recovery at sunset. Growth rates of crabwood were high, and similar in both seasons (2 mm month-1). Leaf thickness and S D were 19% and 47% higher in sun than in shade plants, whereas the opposite was true for S S. We conclude that ΨL greatly affects carbon assimilation of crabwood by reducing g s at noon, although this effect is not reflected on growth rates indicating that other factors offset the effect of g s on Amax.

Modes of transmission of rumen protozoa between mature sheep

2010 ◽  
Vol 50 (6) ◽  
pp. 414 ◽  
Author(s):  
Simon H. Bird ◽  
R. S. Hegarty ◽  
R. Woodgate
Keyword(s):  
Drinking Water ◽  
Rumen Fluid ◽  
Contaminated Water ◽  
Feed Water ◽  
Faecal Material ◽  
Modes Of Transmission ◽  
Rumen Protozoa ◽  
Animal Contact ◽  
Ciliate Protozoa

Three experiments were conducted to evaluate routes by which viable rumen ciliate-protozoa may be transferred between mature sheep. Feed, water and faecal material were tested as possible vectors for protozoal transfer in addition to direct animal to animal contact. In Experiment 1, protozoa-free sheep were either offered or orally dosed with protozoa-contaminated material or allowed contact with faunated animals. The treated sheep were then monitored over a 4-week period for the appearance of protozoa in the rumen. Protozoa were successfully transferred to protozoa-free animals via contaminated water but no transfer occurred via feed or faeces or by direct animal to animal contact. In Experiment 2, the drinking water of penned faunated sheep was found to become contaminated with protozoa within 4–6 h of being placed in the pen. In Experiment 3, nine protozoa-free sheep were grazed in a paddock with a flock of 75 faunated ewes for periods of 1–3 weeks, and protozoa became established in one protozoa-free sheep. The results of these studies suggest that the most likely mode of transfer of protozoal cells from one sheep to another is via water, rather than by rumen fluid contaminating feed, or from faeces of faunated sheep. Further tests are required to demonstrate protozoal transmission via water occur under a range of conditions and inoculum levels.

scholarly journals Ex-vivo cow rumen fluid fermentation: changes in microbial populations and fermentation products with different forages

2018 ◽  
Vol 46 (1) ◽  
pp. 1272-1279 ◽  
Author(s):  
Haitian Fang ◽  
Omar Al-Marashdeh ◽  
Huitong Zhou ◽  
Andriy Podolyan ◽  
Jonathan G. Hickford ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Rumen Fluid ◽  
Microbial Populations ◽  
Fermentation Products

scholarly journals Impacts of the Manaus pollution plume on the microphysical properties of Amazonian warm-phase clouds in the wet season

2016 ◽  
Author(s):  
Micael A. Cecchini ◽  
Luiz A. T Machado ◽  
Jennifer M. Comstock ◽  
Fan Mei ◽  
Jian Wang ◽  
...  
Keyword(s):  
Growth Rates ◽  
Urban Pollution ◽  
Droplet Size Distribution ◽  
Bimodal Distribution ◽  
Anthropogenic Sources ◽  
Cloud Base ◽  
Effective Diameter ◽  
Wet Season ◽  
Coalescence Process ◽  
Microphysical Properties

Abstract. The remote atmosphere over the Amazon can be similar to oceanic regions in terms aerosol conditions and cloud type formations. This is especially true during the wet season. The main aerosol-related disturbances over the Amazon have both natural sources, such as dust transport from Africa, and anthropogenic sources, such as biomass burning or urban pollution. The present work considers the impacts of the latter on the microphysical properties of warm-phase clouds by analyzing observations of the interactions between Manaus city and its surroundings, as part of the GoAmazon2014/5 Experiment. The analyzed period corresponds to the wet season over a tropical rain forest (i.e., Feb to Mar 2014 and corresponding to the first Intensive Operating Period (IOP1) of GoAmazon2014/5), and the droplets observed are in the range 1 μm ≤ D ≤ 50 μm. The wet season largely presents a clean background atmosphere characterized by frequent rain showers. As such, the contrast between background clouds compared to those affected by the Manaus pollution can be observed and detailed. The focus is on the characteristics of the initial microphysical properties in cumulus clouds predominantly at their early stages. The pollution-affected clouds are found to have lower effective diameters and higher droplet number concentrations. The average differences range from 10% to 40% for the effective diameter and are as high as 1000% for droplet concentration across different vertical levels (0 to 3200 m). The growth rates of droplets with altitude are slower for pollution-affected clouds (2.90 compared to 5.59 μm km-1), as explained by the absence of bigger droplets at the onset of cloud development. Clouds under background conditions have higher concentrations of larger d roplets (e.g., > 20 μm) close to cloud base, which would contribute significantly to the growth rates through the collision-coalescence process. The droplet size distribution (DSD) overall shape do not appear to be predominantly determined by updraft strength, especially beyond the 20 μm range. The aerosol conditions play a major role in that case. However, the updrafts modulate the DSD concentrations and are responsible for the vertical transport of water in the cloud. The larger droplets found in background clouds are associated with weak water vapour competition and a bimodal distribution of droplets in the lower levels of the cloud, that enables an earlier initiation of collision-coalescence process. This study shows that the pollution produced by Manaus affects significantly warm-phase microphysical properties of the surrounding clouds by changing the initial DSD formation. The corresponding effects on ice-phase processes and precipitation formation should be the focus of future endeavors.

scholarly journals Quantitative effects of defaunation on rumen fermentation and digestion in sheep

1985 ◽  
Vol 54 (1) ◽  
pp. 105-119 ◽  
Author(s):  
J. B. Rowe ◽  
A. Davies ◽  
A. W. J. Broome
Keyword(s):  
Organic Matter ◽  
Population Density ◽  
Volatile Fatty Acids ◽  
Rumen Fluid ◽  
Dietary Carbohydrate ◽  
High Population Density ◽  
Irreversible Loss ◽  
Faecal Excretion ◽  
Carbon And Nitrogen ◽  
End Products

1. Studies on the quantitative significance of protozoa on carbon and nitrogen digestion and metabolism in the rumen were carried out in sheep given a diet of pelleted concentrate (500 g/d) and chopped hay (500 g/d).2. Measurements were made of apparent digestibility; flows of organic matter and dietary and microbial non-ammonia N (NAN) (using 15NH+4) to the duodenum; and rates of production, interconversion and metabolism of the major C fermentation end-products (from mathematical modelling of 14C isotope values).3. The population density of bacteria in the rumen increased as a result of defamation (28.6 compared with 8.2 x 10° organisms/ml). This high density was associated with greater utilization of volatile fatty acids (VFA) within the rumen.4. The rate of irreversible loss (IL) of bicarbonatefcarbon dioxide from the rumen was greater in the defaunated animals (98.5 v. 57.2 g C/d) but the IL from the blood was greater in the faunated group (138.6 v. 106.1 g C/d). This is consistent with the hypothesis that the high population density of bacteria found in the rumen fluid of defaunated animals may result in increased fermentation of rumen VFA and digestible dietary carbohydrate, thereby increasing the output of CO2 from the rumen and reducing the quantity of VFA (hence energy) available to the host.5. There was no difference in the flow of organic matter (OM) to the duodenum but there was a higher faecal excretion of OM in defaunated animals (apparent OM digestibility: 0.72 in faunated, 0.67 in defaunated).6. Defamation did not significantly increase the flow of NAN to the duodenum, the percentage of duodenal NAN of bacterial origin or the quantity of microbial NAN synthesized/g organic matter fermented. Faecal excretion of NAN was higher in defaunated animals (5.3 v. 3.6 g N/d).

Variation in the in vitro hydrolytic activity of rumen and faecal inocula

2002 ◽  
Vol 2002 ◽  
pp. 166-166 ◽  
Author(s):  
M. Afdal ◽  
F.L. Mould ◽  
C. Rymer ◽  
E. Owen ◽  
D.I. Givens
Keyword(s):  
Rumen Fluid ◽  
Hydrolytic Activity ◽  
Potential Method ◽  
Gas Production ◽  
Microbial Populations ◽  
Fluid Medium ◽  
Faecal Material ◽  
Evaluation Systems

Considerable efforts have been made regarding the use of faecal material to provide a microbial inoculum for in vitro feed evaluation systems. However total gas production, rate of gas release and the extent of degradation of feeds incubated using faecal inoculum are lower than those incubated in a rumen fluid medium. It has been suggested that this is due to lower microbial activity, a consequence of the different microflora and reduced microbial numbers (e.g. Mauricio, 1999). Microbial populations are dynamic so, as their enzyme activity profiles change rapidly, little information is obtained from examining these. However, their hydrolytic activity as reflected by their ability to degrade specific substrates can be simply measured and provides a potential method with which to assess the quality of inocula with respect to their use in in vitro systems. The data presented here are from a larger study in which the differences between the hydrolytic activity of faecal material and rumen contents as influenced by the time of sampling were assessed in vitro.

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