The metabolic excretion and true digestibilities of nitrogen and fat by cattle and sheep with particular reference to forage-faeces relationships

1972 ◽  
Vol 23 (5) ◽  
pp. 879 ◽  
Author(s):  
KW Moir ◽  
AJ Swain

The non-dietary nitrogen excretion in faeces and the true digestibility of nitrogen determined in 23 digestibility experiments with grasses were respectively 0.60 ± 0.063 g N per 100 g forage organic matter and 84.9 ± 2.29%, when estimated from the regression of digestible nitrogen on percentage dietary nitrogen, and 0.60 ± 0.026 g N and 82.9 ± 2.33%, when estimated from data obtained by separating dietary and nondietary faecal nitrogen with detergent solution. The true digestibility of nitrogen, estimated similarly in four digestibility experiments with legumes, was higher than that in grasses. Among grasses and legumes but not within grasses, digestible organic matter was more closely correlated with non-dietary faecal nitrogen than with total faecal nitrogen. Among and within grasses and legumes the apparently digestible protein was more closely correlated with faecal nitrogen when undigested dietary nitrogen as a proportion of total faecal nitrogen was included as a variate in a multiple regression equation. The endogenous excretion of saponifiable fat was negligible and its average true digestibility estimated from regression analysis was 52. .6 ± 5.55 %.

1976 ◽  
Vol 27 (1) ◽  
pp. 139 ◽  
Author(s):  
JG Mulholland ◽  
JB Coombe ◽  
WR McManus

Individually penned Border Leicester x Merino wethers, aged 11 months, were fed ad lib. for 16 weeks on a basal ration of ground, pelleted oat straw, urea and minerals, supplemented with 0, 5, 10, 15, 20, 30 or 40% starch. The diets contained equal percentages of nitrogen and minerals. Dry matter intake reached a maximum of 2000 g/day with 30% starch; above this starch level, digestive disturbances were observed. Organic matter digestibility was increased by the addition of starch, but cellulose digestibility was depressed by as much as 18 units with the addition of 30% starch. Up to 10% the starch level had little effect on cellulose digestibility. Liveweight change was significantly correlated with digestible organic matter intake, mean daily weight gains varying from 22 g with no starch to 104 g with 30% starch. However, a large percentage of the liveweight gain was as total body water, and body energy storage increased appreciably only when the diet contained at least 20% starch. The inclusion of 5% starch slightly depressed both intake and liveweight gain. Daily clean wool production was significantly increased at starch levels higher than 20% and ranged from 5.3 to 7.5 g/day with 0 and 40% starch respectively. Increasing levels of starch had little effect on apparent nitrogen digestibility, but resulted in a substantial increase in nitrogen retention through a reduction in urinary nitrogen excretion. Serum urea levels fell from a mean of 42 mg/100 ml during the first week to 31 mg/100 ml during subsequent periods, with no significant differences between diets. With the general exception of potassium, mineral balances were positive or close to zero throughout the experiment.


1963 ◽  
Vol 5 (1) ◽  
pp. 11-16 ◽  
Author(s):  
J. P. Langlands ◽  
J. L. Corbett ◽  
I. McDonald ◽  
G. W. Reid

SUMMARYThe mean daily digestible organic matter intake (D) of each of 47 adult sheep during a grazing period of mean length 48 days was estimated by the chromium sesquioxide/faecal nitrogen technique. Mean live-weights (W) and mean daily weight gains (G) were also measured.The regression of D on W and G, and the underlying or functional relationship between D, W and G were both estimated. From the underlying relationship, the preferred equation, the maintenance requirement of a 100 lb. sheep at pasture is estimated to be 1·02 lb. digestible organic matter daily. This value is 24% higher than the corresponding value for housed sheep obtained previously by us.This result is compared with other estimates of the energy cost of grazing and it is concluded that further work is needed in order to define those circumstances which elevate the maintenance requirements of grazing animals.


1983 ◽  
Vol 100 (1) ◽  
pp. 13-23 ◽  
Author(s):  
J. B. Moran

SUMMARYThe results of 62 comparative digestibility and nitrogen balance trials of Asiatic water buffalo and Zebu cattle fed the same roughage or mixed diet were analysed to test for species differences in various nitrogen input-output relationships. The influence of dietary metabolizable energy content on the utilization of dietary or apparently digested nitrogen (ADN) was also investigated.There was no difference between buffaloes and Zebus in their ability to digest dietary nitrogen. The true nitrogen digestibility was calculated to be 81% and the metabolic faecal nitrogen excretion to be 0·36 g N/lOOg dry-matter intake. The buffaloes had lower rates of excretion of urinary nitrogen per unit increase in ADN, and at the same intake of ADN (143 mg/kg live weight/day), they had the higher nitrogen balance: 58v.48 mg/kg live weight/day. Dietary metabolizable energy content did not affect the utilization of digested nitrogen.Estimates of metabolic faecal nitrogen and endogenous urinary nitrogen excretions and of maintenance requirements for digested nitrogen were similar to those of tropical large ruminants reported by other workers. On low-quality (0·8% N) or medium-quality (1·6% N) diets, it was calculated that buffaloes would have nitrogen balances.


1967 ◽  
Vol 15 (1) ◽  
pp. 7 ◽  
Author(s):  
GD Brown ◽  
A.R. Main

The nitrogen requirements of some female euros (Macropus robustus) were determined by means of nitrogen balance feeding trials. The average minimum dietary nitrogen requirement for the maintenance of nitrogen equilibrium was 1.99 g/day or 309 mg/day per kgW*0.73. The metabolic faecal nitrogen output of the euros, determined indirectly, was estimated to be 0.27 g/100 g dry matter intake. The minimum digestible nitrogen requirements of the euros were 160 mg/day per kgW*0.73, equivalent to approximately 1 g digestible nitrogen per day. The minimum urinary nitrogen excretion of the euros, at dietary nitrogen intakes of approximately 1 g/day, was an average of 34 mg/day per kgW*0.73. Comparison of the results obtained with data for eutherian species reported in the literature indicates that the nitrogen requirements and urinary nitrogen excretion of this species is markedly less than that of eutherian species. The results are briefly discussed in relation to survival of the euro in the arid environment of the Pilbara district of Western Australia.


1969 ◽  
Vol 73 (1) ◽  
pp. 99-111 ◽  
Author(s):  
V. C. Mason

SUMMARY1. Three methods, based on treatment with neutral detergent or acid detergent, or involving ultrasonic disintegration, are described and compared for the direct estimation of undigested dietary nitrogen in individual samples of sheep faeces. Estimates of the true digestibility of the nitrogen in several sheep diets derived from analyses performed with these methods agreed well with each other, and were in accord with published estimates, derived by extrapolation techniques. Two other methods, based on treatment with phenol–acetic acid–water, and lysozyme–trypsin, respectively, were found to be unsuitable for such estimates.2. The quantitative distribution of nitrogen between undigested dietary residues, bacterial residues, endogenous debris residues and the water soluble fraction was determined chemically. It was concluded that 57–81% of the non-dietary faecal nitrogen was associated with bacterial material.3. Indirect evidence suggested that most of the bacterial nitrogen in faeces originated in the rumen.


1972 ◽  
Vol 78 (3) ◽  
pp. 351-353 ◽  
Author(s):  
K. W. Moir

SUMMARYForages and faeces from 28 digestibility experiments with cattle or sheep were extracted with neutral detergent solution, with and without sodium sulphite, or sequentially extracted with acid-pepsin, ethyl alcohol, diethyl ether and either ammonium oxalate or hot water. Ammonium oxalate was used to extract small amounts of non-protein material not extracted from legumes by hot water. Compared with sequential extraction the average protein-free organic residues after extraction with detergent, with and without sodium sulphite, were significantly lower in legumes and faeces, but not in grasses. The largest differences occurred in faeces from grasses for which the recoveries of cell walls as percentages of the faecal organic matter were found to be 59·2, 62·0 and 66·4 respectively, after extraction with neutral detergent plus sodium sulphite, neutral detergent alone and sequential extraction with various solvents. It was considered that the differences were due to extraction of cell-wall constituents by both detergent and sulphite.


1989 ◽  
Vol 69 (4) ◽  
pp. 1111-1114 ◽  
Author(s):  
J. E. KNIPFEL ◽  
J. A. KERNAN ◽  
E. C. COXWORTH ◽  
R. D. H. COHEN

A trial was conducted to determine the nutritive value for sheep of kochia (Kochia scoparia L. Schrad) grown on saline soil and harvested at the early seed stage and the full bloom stage of maturity. There was a significant decrease in digestible organic matter intake (DOMI) and digestible crude protein intake (DCPI) with increasing kochia maturity (31.6 vs. 23.2 g DOMI kg−0.75 (SE = 0.6; P < 0.05) and 4.22 vs. 1.41 g DCPI kg−0.75 (SE < 0.001; P < 0.05)). Early cut kochia appears to be at least equivalent in digestible energy to alfalfa, but lower in digestible protein. Key words: Kochia, maturity, nutritive value, sheep


1972 ◽  
Vol 23 (1) ◽  
pp. 35 ◽  
Author(s):  
BD Siebert ◽  
PM Kennedy

The addition of 13.6% lucerne to a diet of spear grass increased the total intake of digestible organic matter of cattle by nearly 30%. Further additions (24.5 and 44.9%) increased the total organic matter intake, but decreased the spear grass intake. In cattle, the digestibility of the spear grass portion of the diet appeared to decrease as lucerne was added to the diet. Sheep consumed and digested spear grass poorly, although an addition of 14.4% legume increased both digestibility and intake. Further additions of legume slightly decreased the digestibility of the spear grass. The addition of urea alone did not influence digestion or feed intake by either cattle or sheep. When cattle were fed on spear grass, urea, and minerals, the quantity of organic matter digested was not significantly different from that with a diet of spear grass and 20% lucerne. The digestibility of the spear grass was not influenced by urea and minerals, whereas it decreased with the addition of lucerne. Increased feed consumption was maintained when various components of the mineral supplement were withdrawn, excepting nitrogen and sulphur. The energy derived from diets of spear grass and lucerne or spear grass and minerals appears to be above the maintenance requirements of cattle, but below those of sheep.


1980 ◽  
Vol 31 (1) ◽  
pp. 57-62
Author(s):  
H. A. Birrell

ABSTRACTIn a grazing experiment, the organic matter digestibility of herbage selected by sheep grazing at two stocking rates was determined at monthly intervals over a 9-month period by (i) the in vitro determination of organic matter digestibility of the material collected from sheep fitted with an oesophageal fistula, and (ii) derivation from the prediction of digestible organic matter intake with a faecal nitrogen regression. A comparison of the two techniques confirms the view of other workers that faecal nitrogen indices based on pen feeding trials of green herbage are unreliable for predicting digestibility of green herbage in the field. The bias which is produced by faecal nitrogen regression appears to be associated with the time spent grazing by the animal each day. Relating organic matter digestibility directly to nitrogen content of faeces of grazing sheep (N, g nitrogen/100 g faecal organic matter) and their grazing time (T,h) yielded the following equation:The expression has standard errors (±2·6) similar to those involved in an in vitro determination. It provides a simple technique for estimating digestibility of herbage eaten by grazing sheep, but this may only be applicable to the particular sward conditions.Field estimates of digestibility over summer and autumn by this equation were found to be similar to estimates by a faecal nitrogen expression established from hand feeding sheep with dry summer herbage.


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