The digestion of pasture plants by sheep. III. The digestion of forage oats varying in maturity and in the content of protein and soluble carbohydrate

1969 ◽  
Vol 20 (2) ◽  
pp. 347 ◽  
Author(s):  
JP Hogan ◽  
RH Weston

A comparison has been made of the composition, intake, and digestion of forage oats grown with and without the application of nitrogen fertilizer and harvested at three stages of maturity. The chemical composition of the forages showed the usual changes with maturity. Fertilizer application had little effect on the levels of cell wall constituents but, as expected, decreased the levels of soluble carbohydrate and increased those of total nitrogen, alcohol-soluble nitrogen, and nitrate. The digestibility of organic matter, cell wall constituents, and nitrogen declined with advancing maturity, all three parameters being little affected by the fertilizer treatment. Feed consumption declined only with the most mature diet and was not affected by the fertilizer treatment even though the high nitrogen (HN) diets supplied 4–5 g nitrate nitrogen per day and relatively small amounts of soluble carbohydrate. There was a loss of dietary nitrogen from the stomach with the HN diets and a gain with the low nitrogen (LN). The amount of nitrogen in the digesta leaving the stomach per unit intake of nitrogen increased with maturity. The quantities of protein leaving the stomach were too great to be accounted for as microbial protein, and hence appreciable quantities of plant protein must have passed through the stomach. The digestibility of crude protein in the intestines was not affected either by maturity of the forages or by fertilizer treatment. There was little effect of advancing maturity or fertilizer application on: (a) the extent of digestion of organic matter and the structural carbohydrates in the stomach relative to that occurring in the intestines; (b) the proportion of digestible organic matter derived from rumen volatile fatty acids and amino acids; � the potential value of the metabolizable energy from volatile fatty acids and amino acids to provide net energy for fattening; (d) most parameters associated with the movement of digesta through the stomach. Advancing maturity of the diets was associated with increased expenditure of time in chewing activities.

1969 ◽  
Vol 20 (5) ◽  
pp. 925 ◽  
Author(s):  
JP Hogan ◽  
RH Weston ◽  
JR Lindsay

A study was made of the composition, intake, and digestion of dried Phalaris tuberosa forage that had been harvested at three stages of maturity. Advancing maturity was associated with: (i) decreased food intake; (ii) increased expenditure of time and energy in chewing activities; (iii) decline in the rate of flow of digesta from the abomasum though not from the rumen; (iv) decline in digestibility in the whole tract of organic matter, nitrogen, and the structural carbohydrates; (v) decline in the digestion of fibre in the rumen relative to that occurring in the whole tract; (vi) decline in the quantities of volatile fatty acids and amino acids made available to the animal. By contrast only small differences attributable to maturity were observed in: (i) the distribution of digestion of organic matter between stomach and intestines; (ii) the digestibility of nitrogen other than ammonia in the intestines; (iii) the proportions of digestible organic matter derived from volatile fatty acids and amino acids; (iv) the proportions of individual amino acids in the digesta passing to the intestine. It was calculated that microbial piotcin contributed 33, 38, and 47% of the protein passing from the stomach to the intestincs with the diets of advancing maturity. Most of the remaining protein was presumably of dietary origin. About 80% of the crude protein in the digesta was present in the form of amino acids, and the quantities of amino acids released in the intestines were calculated to be equivalent to 64–66 g/100 g crude protein intake. With advancing maturity of the diets the plasma levels of the essential ammo acids except lysine, histidine, and arginine declined; there was little effect of diet on the plasma levels 01 non-essential amino acids. However, relative to total essential amino acids, the ratios of valine and leucine decreased with advancing maturity of the diet while those of lysine, histidine, glutamate, glycine, alanine, and serine increased. * Part 111, Aust. J. Agric. Res., 1969, 20, 347.


1968 ◽  
Vol 19 (3) ◽  
pp. 419 ◽  
Author(s):  
RH Weston ◽  
JP Hogan

The production of volatile fatty acids (VFA) in the rumen of sheep was estimated by isotope dilution techniques. The 12 diets used consisted of dried ryegrass and forage oats and covered a wide range of levels of cell wall constituents (46–40% of the organic matter), crude protein (6–32%), and soluble carbohydrate (5–18%). Each diet was offered at a level equal to approximately 90% of the sheep's ad libitum intake. The production of VFA was correlated with the total amount of organic matter digested in the alimentary tract (r = 0.93–0.95). The mean VFA production per 100 g of organic matter digested in the alimentary tract was equivalent to 56.8 g, 243 kcal, or 0.85 mole. Values for individual diets varied about these means with a coefficient of variation of 6–7%. Rates of VFA production in, and VFA absorption from the rumen were correlated with VFA concentration in rumen liquor (r = 0.67, r = 0.67) and the rumen VFA pool (r = 0.81, r = 0.79). Approximately 76% of the VFA produced in the rumen was absorbed from the rumen, 19% was absorbed from the omasum and abomasum, and 5% passed from the abomasum to the intestines.


1971 ◽  
Vol 22 (1) ◽  
pp. 139 ◽  
Author(s):  
RH Weston ◽  
JP Hogan

Subterranean and berseem clovers, harvested at early and late stages of maturity, were dried and offered to sheep ad libitum, or at about 90 % of ad libitum intake. Feed consumption and the times spent in ruminating and eating were measured when the forages were offered ad libitum and several aspects of digestion were studied at the restricted level of feeding. The effects of maturity on (i) forage chemical composition, (ii) nutrient digestibility, (iii) parameters relating to the movement of digesta through the stomach, (iv) ruminal volatile fatty acid production, (v) the molar proportions of individual amino acids in abomasal digesta and peripheral blood plasma, (vi) nitrogen balance, and (vii) the time and energy expenditure in ruminating and eating, were generally the same with these clovers as has been observed previously with grasses. Substantial amounts of nutrients were derived from forages harvested in the immature state, the consumption of which provided about 1200 g organic matter per day. It was calculated that under conditions of ad libitum feeding about 500 g of volatile fatty acids was produced in the rumen and 160-230 g of crude protein was digested in the intestines per day. High mean values for nitrogen balance were obtained with immature subterranean clover but the variation between sheep was large. The levels of amino acids in blood plasma were also exceptionally high with this diet. The data obtained on the digestion of immature clover forages were compared with those obtained previously with immature grass forages. The patterns of digestion were generally very similar for both types of forages and any differences observed could usually be ascribed to the higher feed intake with the clovers. The forages had similar capacities to furnish volatile fatty acids in the rumen and digested crude protein in the intestines. The calculated energy expenditure in eating and ruminating, however, was slightly lower for the clovers. The data were interpreted to indicate that if immature clovers are superior to immature grasses in promoting animal production, the superiority cannot be attributed to an inherent capacity of clovers to provide the animal with a more favourable balance of nutrients.


Author(s):  
Jinyi Qin ◽  
Rui Zhang ◽  
Ruiwen Yang ◽  
Jiao Fang ◽  
Yu Zhang ◽  
...  

Abstract Sewage sludge was subjected to hydrothermal fueling (HTF) (330 °C for 40 min), obtaining hydrochar at 13.5 MJ kg−1. The higher heating value (HHV) of the raw sludge was related to its fatty acid content. The results showed that although the higher heating value (HHV) of the raw sludge was related to its fatty acid content, with the intensification of HTF, the increase in aliphatic/cyclic amino acids determined the production of HHV in the hydrochar. In order to increase the content of fatty acids and amino acids, the sludge was fermented. However, the Bacteroidetes consumed the organic matter too early, which was detrimental to the production of HHV. Therefore, appropriate sludge fermentation is recommended to restrict excessive Bacteroidetes proliferation, decompose lipids to saturated fatty acids, and convert proteins to aliphatic/cyclic amino acids to increase the efficiency of converting sludge to fuel.


1980 ◽  
Vol 94 (1) ◽  
pp. 219-227 ◽  
Author(s):  
C. G. Wernli ◽  
R. J. Wilkins

SummaryGrass silage (21.0 % D.M.) was given ad libitum to sheep together with supplements of rolled barley, dried-grass pellets or dried-grass wafers at 12 and 25 g organic matter (OM)/kg0·75.Intake of silage was greater with supplement at 12 g/kg0·75 but total intake of OM and digestible organic matter (DOM) increased with increasing supplement. Intake of OM was higher with the pellet supplement than with other supplements. Intake of DOM, however, did not differ between the pellet and barley treatments, but was lower with wafers.Concentrations of ammonia and total volatile fatty acids and the molar proportions of butyric and higher volatile fatty acids were higher when silage was supplemented with barley than with dried grass. Mean rumen retention times of silage and of supplement were highest in the barley-supplemented treatments. Dried-grass wafers were retained longer than dried-grass pellets. Supplement treatments did not differ significantly for eating and ruminating times, rumen fluid volume and pH, digestion rate in the rumen and nitrogen retention.At the low supplement rate silage consumption may have been controlled by factors associated directly with the silage, whereas at the high rate intake was limited either by physical factors or by the potential energy demand of the animals.


1957 ◽  
Vol 1957 ◽  
pp. 3-15 ◽  
Author(s):  
D. G. Armstrong ◽  
K. L. Blaxter ◽  
N. McC. Graham

The work of the late Sir Joseph Barcroft and his collaborators (see Elsden & Phillipson, 1948) left little doubt that, in ruminants, the end products of the bacterial dissimilation of dietary carbohydrate included large amounts of the steam-volatile fatty acids—acetic, propionic and butyric acids. More recently, el Shazly (1952a, b) has shown that the steam-volatile fatty acids also arise together with ammonia during the bacterial breakdown of amino-acids in the rumen. Studies by Pfander & Phillipson (1953) and Schambye (1955) further indicate that the acids are absorbed from the digestive tract in amounts that suggest they make a major contribution to the energy requirement of the animal. Quantitative data relative to the amounts absorbed, however, are difficult to obtain. Carroll & Hungate (1954) have calculated that in cattle some 6,000-12,000 Cal. of energy are available from the acids produced by fermentation in the rumen. With sheep, Phillipson & Cuthbertson (1956) have calculated from the results of Schambye (1951a, b; 1955) that at least 600-1,200 Cal. of energy in the form of steam-volatile fatty acids could be absorbed every 24 hrs. Since the fasting heat production of the steer is about 6,500 Cal./24 hrs. and that of the sheep about 1,100 Cal./24 hrs. it is clear that if the fatty acids can be utilised efficiently by the body tissues, they could make a major contribution to the energy requirements, at least those for maintenance.


1995 ◽  
Vol 31 (7) ◽  
pp. 169-179 ◽  
Author(s):  
T. Hvitved-Jacobsen ◽  
K. Raunkjær ◽  
P. H. Nielsen

The main objective was to study the anaerobic transformation of organic matter and sulfide production during wastewater transportation. Emphasis was on the transformation of easily biodegradable organic matter in terms of volatile fatty acids (VFA). Samples from two intercepting pressure mains located in the Northern part of Jutland, Denmark, were taken. The concentration of VFA in the wastewater varied considerably during day and night, being typically between 5 and 50 g/m3. A net production as well as a net removal of VFA was seen during transportation in the pressure mains probably depending on the quality and quantity of the organic matter. Typically 85% of the VFA was acetate and 10% propionate; the remainder was formate, n-butyrate and iso-butyrate. Observed sulfide production rates from the sewer biofilms were typically 0.05 and 0.005 g S/m2 h at 12 and 4 °C, respectively. A high sulfide production rate corresponded with a high VFA concentration. TOC removal was observed in the pressure mains.


1974 ◽  
Vol 14 (67) ◽  
pp. 161 ◽  
Author(s):  
PJ Michell

The total concentration and the relative proportions of the volatile fatty acids (VFA) were measured in rumens of sheep fed 78 single species pasture samples. The pastures consisted of regrowths of white clover (Trifolium repens cv. Grasslands Huia), Manawa regrass (Lolium perenne x multiflorum cv. Grasslands Manawa), Ariki ryegrass (Lolium (multiflorum x perenne) x L. perenne cv. Grasslands Ariki), perennial ryegrass (Lolium perenne cv. Tasmania No. 1) , Currie cocksfoot (Dactylis glomerata cv. Currie) and Apanui cocksfoot (Dactylis glomerata cv. Grasslands Apanui), cut eight times between May, 1969 and August, 1970. Sheep fed cocksfoot had lower VFA concentrations, higher proportions of acetate (HAc) and lower proportions of butyrate (HBu) than sheep fed white clover and ryegrass (P < 0.05). They also had lower proportions of propionate (HPr) than sheep fed ryegrass (P < 0.05). Sheep fed white clover had higher proportions of valerate (HVa) than those fed the grasses (P < 0.05). There were no significant (P < 0.05) seasonal differences in total VFA concentration but HAc was lowest with spring pasture (P < 0.05) and HBu was lowest with autumn pasture (P < 0.05). Total VFA concentration was positively related to digestibility (DMD) (r = +0.52, P < 0.01) but species differences occurred and at similar DMD, white clover produced higher concentrations than ryegrass (P < 0.05) which produced higher concentrations than cocksfoot (P < 0.01). The overall relation between total VFA and intake (DMI) was weak but seasonal differences occurred and at similar levels of DMI, winter pasture produced higher VFA concentrations than spring-summer pasture (P < 0.01). The proportion of HPr was positively related to VFA concentration (r = +0.53, P < 0.01) and to water soluble carbohydrate (WSC) content (r = +0.51, P < 0.01) and relations with DMD and DM1 were weak and non-significant (P > 0.05).


1982 ◽  
Vol 30 (5) ◽  
pp. 767 ◽  
Author(s):  
DW Dellow ◽  
ID Hume

4. Digestion in the stomach, small intestine and large intestine of the red-necked pademelon (Thylogale thetis), the tammar wallaby (Macropus eugenii) and the eastern grey kangaroo (M. giganteus) fed on chopped lucerne hay freely was estimated in a slaughter experiment by reference to chromic sesquioxide added to the diet. Concentrations of volatile fatty acids and ammonia, and pH, indicated that microbial activity in the forestomach and large intestine (caecum and proximal colon) was extensive. In all 3 species virtually all of the soluble carbohydrate, 17% of apparently digestible crude protein, 62 to 65% of apparently digestible organic matter and 82 to 85% of digestible acid-detergent fibre were digested in the forestomach. There was a progressive loss of dietary substrates along the length of the forestomach; readily fermentable carbohydrate was digested largely in the sacciform forestomach and cranial region of the tubiform forestomach, and the rate of apparent loss of organic matter decreased along the tubiform forestomach.


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