The use of chromium oxide and faecal nitrogen concentration to estimate the pasture intake of Merino wethers

1963 ◽  
Vol 14 (2) ◽  
pp. 257 ◽  
Author(s):  
LJ Lambourne ◽  
TF Reardon
Keyword(s):  
Organic Matter ◽  
Feed Intake ◽  
Nitrogen Concentration ◽  
Linear Equations ◽  
Large Measure ◽  
Feed Digestibility ◽  
Wide Range ◽  
Digestible Organic Matter ◽  
Faecal Nitrogen ◽  
Maintenance Requirements

Statistical analysis of the results of digestion trials on a wide range of fresh pasture herbages shows that their digestibility might be estimated as the intake factor or feed faeces ratio (Y) from the equation: YO.M. = (2.04 – 0.24XN ± 0.186X2N) ± 0.53 where YO.M. is the intake factor for organic matter, and XN is the percentage of nitrogen in faecal organic matter. The results were subdivided arbitrarily into "summer" (September–April) and "winter" (May–August) periods, and these proved to yield significantly different linear equations. The summer regression yielded higher intake factors (corresponding to 2–3% higher digestibility) for a given value of faecal nitrogen percentage. This subdivision reduced the standard deviation from regression only slightly, to about 0.50, which amounts to ± 17% for pasture of 75% digestibility. These equations give considerably lower values of digestibility for a given nitrogen concentration than regressions hitherto published. The present pooled equation, based on short leafy herbage, probably gives sounder estimates for grazing sheep than do the existing equations derived from trials with more mature herbages. When sheep with a wide range in body weight were all fed a maintenance ration, it was found that feed digestibility was not detectably reduced at high levels of feeding. The undoubtedly higher feed intake of grazing than of pen-fed animals, due in large measure to their higher maintenance requirements, therefore may not cause the reduction in digestive efficiency, and thus the bias in estimates of feed intake, that has been supposed. On the basis of the pooled regression, which is felt to be preferable to a subjectively selected "seasonal" equation, estimates of the intake of digestible organic matter (D.O.M.) by sheep in metabolism pens fed on fresh pasture herbage averaged 97 ± 22% of the true figures, or ± 80 g D.O.M.

The use of faecal nitrogen as an index for estimating the consumption of herbage by grazing animals

1963 ◽  
Vol 61 (1) ◽  
pp. 33-43 ◽  
Author(s):  
G. W. Arnold ◽  
M. L. Dudzinski
Keyword(s):  
Organic Matter ◽  
Nitrogen Concentration ◽  
Linear Equations ◽  
Slope Position ◽  
Seasonal Differences ◽  
Faecal Nitrogen ◽  
Independent Variable ◽  
Regression Relations ◽  
The Relationship ◽  
Better Than

Data from thirty-five digestibility trials with sheep in metabolism cages were used to investigate statistically the relationships between organic matter intake (I), faecal organic matter output (F), and the nitrogen concentration in faecal organic matter (N).The data fell easily into groups due to botanical or seasonal differences in the feed. These groups of data were homogeneous and provided highly significant linear equations of the forms I = bF + cFN and I = a + cFN. When compared these groups of data sometimes showed differences in slope, position or both. A quadratic expressionI = bF + cFN + dFN2was found to accommodate a majority of the data but to be less precise than I = a + cFN.A further expression incorporating N as an independent variable was also examined,I = a + cFN2 + eN.This expression, although far from being universally adequate, proved to be generally better than existing formulae. When applied to the data of Greenhalgh et. al. (1960), it substantially reduced heterogeneity between data for spring and data for summer pastures.Causes of variation in the relationship between organic-matter intake and nitrogen in faeces, and some of the hazards of extrapolation from empirical regression relations, are discussed.

Estimates of the energy required for maintenance by adult sheep 2. Grazing sheep

1963 ◽  
Vol 5 (1) ◽  
pp. 11-16 ◽  
Author(s):  
J. P. Langlands ◽  
J. L. Corbett ◽  
I. McDonald ◽  
G. W. Reid
Keyword(s):  
Organic Matter ◽  
Energy Cost ◽  
Functional Relationship ◽  
Adult Sheep ◽  
Maintenance Requirement ◽  
Digestible Organic Matter ◽  
Faecal Nitrogen ◽  
Grazing Period ◽  
The Mean ◽  
Maintenance Requirements

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.

Stimulation of wool growth by thyroxine implantation. II. Feed intake of grazing Merino wethers treated repeatedly with thyroxine.

1964 ◽  
Vol 15 (4) ◽  
pp. 676 ◽  
Author(s):  
LJ Lambourne
Keyword(s):  
Organic Matter ◽  
Feed Intake ◽  
Sheep Grazing ◽  
Wool Production ◽  
Wool Growth ◽  
Digestible Organic Matter ◽  
The Difference ◽  
Maintenance Requirements ◽  
Substantial Rise ◽  
Stimulation Of

Estimates have been made of the feed intake of wethers that received implantations of 60 mg thyroxine every 3 months, and of untreated sheep, grazing together. The estimated intake of digestible organic matter (D.O.M.) by treated wethers was higher than that of controls in 24 out of 27 measurement periods. The difference in feed intake was least in the iirst month after implantation, when the treated sheep lost weight, and greatest in the second and third months when the treated sheep were regaining weight. The overall increase in intake resulting from thyroxine treatment (20–25%) was greater than the increase in wool production (7% greasy weight, 3-7 % clean weight), and the efficiency of wool production was therefore lower in thyroxinetreated wethers. From the relationships between feed intake and rate of weight change it was concluded that in the month after implantation, when pulse rates indicated a substantial rise in metabolic rate, the maintenance feed requirement was raised from about 560 g to about 780 g D.O.M. per day. Observations in two winters with recently shorn sheep gave estimates of maintenance requirements for untreated wethers ranging from 850 to 1300 g D.O.M. per day. During recovery from repeated thyroxine implantation the wethers gained in weight no more efficiently than the controls. The mechanism of action of exogenous thyroxine is discussed in the light of these and other data.

The utilization of spear grass (Heteropogon contortus). I. Factors limiting intake and utilization by cattle and sheep

1972 ◽  
Vol 23 (1) ◽  
pp. 35 ◽  
Author(s):  
BD Siebert ◽  
PM Kennedy
Keyword(s):  
Organic Matter ◽  
Feed Intake ◽  
Feed Consumption ◽  
Total Organic Matter ◽  
Mineral Supplement ◽  
Heteropogon Contortus ◽  
Total Intake ◽  
Digestible Organic Matter ◽  
Maintenance Requirements ◽  
Cattle And Sheep

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.

The estimation of the intake of grazing sheep II. Application of faecal nitrogen regressions to a group of grazing sheep

1962 ◽  
Vol 59 (3) ◽  
pp. 349-353 ◽  
Author(s):  
G. R. Pearce ◽  
J. E. Vercoe ◽  
D. E. Tribe
Keyword(s):  
Organic Matter ◽  
Feed Intake ◽  
General Pattern ◽  
Live Weight ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Lolium Rigidum ◽  
Digestible Organic Matter ◽  
Faecal Nitrogen ◽  
Grazing Sheep

1. Recordings of faecal organic matter (O.M.), faecal N% (O.M. basis) and live weight, were made over 52 consecutive weekly periods on ten Corriedale wethers grazing a pasture consisting mainly of Wimmera rye-grass (Lolium rigidum Gaud.) with some subterranean clover (Trifolium subterraneum) in a Mediterranean-type environment. The amount of available O.M. and its N% were also recorded.2. By applying regressions of (i) the ratio of O.M. feed intake to O.M. faecal output on faecal N% and (ii) the N% in the O.M. intake on faecal N%, to the above observations it was possible to estimate the following quantities: O.M. and digestible organic matter (D.O.M.) intake, N and digestible N intake and O.M. digestibility percentage.3. The patterns of O.M. and D.O.M. intake, and N and digestible N intake are described. Similar patterns exist for each of these quantities. Two maxima, a large one in the spring and a smaller one in the autumn, and two minima, one in the summer and one in the winter, are exhibited. The values for these various maxima and minima are presented in the text.4. Attention is drawn to variations from the general pattern for these quantities and factors which could influence these patterns are mentioned.

Effect of environment on the maintenance requirements of Merino wethers

1963 ◽  
Vol 14 (2) ◽  
pp. 272 ◽  
Author(s):  
LJ Lambourne ◽  
TF Reardon
Keyword(s):  
Small Groups ◽  
Nitrogen Concentration ◽  
Daily Intake ◽  
Cost Of Locomotion ◽  
Digestible Organic Matter ◽  
Faecal Nitrogen ◽  
Maintenance Requirements ◽  
The Relationship ◽  
Energy Cost Of Locomotion ◽  
Stimulation Of

Small groups of Merino wethers were maintained at virtually constant liveweight in four "environments" and their maintenance feed requirements estimated from the relationship between their fluctuations in liveweight over 14-day periods and their feed intakes, measured directly or estimated by chromium oxide dilution and faecal nitrogen concentration. When adult wethers of equal size but a varying degree of fatness were fed on fresh pasture herbage in metabolism pens, liveweights of 26, 32, and 46 kg could be maintained on a daily intake of approximately 200, 300, and 420 g digestible organic matter (D.O.M.) respectively. When the metabolism pens were placed outdoors in winter the maintenance requirements rose, the rise appearing to be greatest for the thin sheep. When wethers were allowed to graze for about 1½ , 2½, and 4 hr in abundant pasture, liveweights of 26, 33, and 46 kg were maintained on intakes of approximately 420, 480, and 490 g D.O.M. respectively. When the same wethers were allowed to graze freely and weight was controlled by the scarcity or abundance of the pasturage, the same liveweights were maintained on intakes of about 750, 780, and 560 g D.O.M. respectively. The rise in maintenance requirements on short pasture seems too great to be explained by the increased energy cost of locomotion and grazing. The possibility of an endocrine stimulation of metabolic rate is pointed out.

The feed intake of grazing cattle. II. The influence of size of animal on feed intake

1961 ◽  
Vol 3 (03) ◽  
pp. 251-260 ◽  
Author(s):  
W. Holmes ◽  
J. G. W. Jones ◽  
R. M. Drake-Brockman
Keyword(s):  
Organic Matter ◽  
White Clover ◽  
Feed Intake ◽  
Live Weight ◽  
Chromic Oxide ◽  
Grazing Cattle ◽  
Continuous Grazing ◽  
Digestible Organic Matter ◽  
Faecal Nitrogen

1. Two experiments each with 3 dry cows, 3 heifers and 3 calves were carried out in 1959 and 1960 under uniform continuous grazing conditions on a ryegrass-white clover sward to measure individual feed intake by the chromic oxide-faecal nitrogen method.2. Estimates of digestibility were high (70–82% in organic matter) and there was evidence that calves selected a diet of higher digestibility than cows.3. Mean daily estimates of organic matter intake were for cows (1300 lb. live-weight) 23·5 lb., for heifers (790 lb. live-weight) 20·8 lb. and for calves (450 lb. live-weight) 14·3 lb. Corresponding digestible organic matter intakes were 17·4, 15·3 and 11·0 lb.4. Relationships between digestible organic matter intake and liveweight were calculated and the merits of the exponents 0·62 and 0·73 of liveweight discussed.5. The results were compared with accepted cow equivalent standards and, regardless of the exponent chosen, agreed with the system which adopts higher values for young grazing cattle.

Studies of natural herbage of the sub-tropics I. The digestibility of herbage grazed by cattle

1962 ◽  
Vol 58 (3) ◽  
pp. 387-391 ◽  
Author(s):  
J. H. Topps
Keyword(s):  
Organic Matter ◽  
Dairy Cattle ◽  
Protein Content ◽  
Crude Protein ◽  
Nitrogen Concentration ◽  
Crude Protein Content ◽  
Faecal Nitrogen ◽  
Digestible Crude Protein ◽  
Cattle Faeces ◽  
Organic Matter Digestibility

1. In two continuous digestibility trials carried out in 1960 and 1961, groups of three wether sheep were fed on oven-dried herbage which had been selectively collected from natural pastures during December 1959 to March 1960 and December 1960 to March 1961. The organic matter digestibility and the digestible crude protein content of the herbage and the nitrogen concentration in faeces were measured over periods of 5 days. The fresh faeces of dairy cattle grazing the natural pastures were regularly sampled and analysed. Regressions of organic matter digestibility and digestible crude protein content on faecal nitrogen were evaluated. From these equations and the composition of the dairy cattle faeces the digestibility of the herbage grazed was calculated.2. The herbage consumed by the cattle had a significantly higher organic matter digestibility and digestible crude protein content than the collected material. This difference, which increased as the season progressed, indicates that dairy cattle became increasingly selective in their grazing as the pasture deteriorated in quality.3. There was a marked yearly difference in digestibility-faecal nitrogen relationships and in the quality of the consumed forage. The grass eaten in 1959-60 had a higher digestibility and lower digestible crude protein content than in the following year. These differences may be part attributable to a seasonal difference in rainfall.4. The organic matter digestibility of the grazed herbage ranged from 52·71 to 65·03% and the digestible crude protein content from 3·08 to 7·43% For milk production, the herbage consumed is low in digestible protein in relation to the total amount of digestible nutrients.

The feed intake of grazing cattle. I. Feed intake of dairy cows on strip and free grazing

1960 ◽  
Vol 2 (2) ◽  
pp. 131-139 ◽  
Author(s):  
W. Holmes ◽  
H. El Sayed Osman
Keyword(s):  
Feed Intake ◽  
Live Weight ◽  
Feed Consumption ◽  
Feed Digestibility ◽  
Significant Difference ◽  
Milk Cows ◽  
Faecal Nitrogen ◽  
Free Grazing ◽  
The Difference ◽  
Strip Grazing

1. Eight Ayrshire milk cows were grazed for four 3-week periods from July to October 1957 in a balanced sequence on two strip-grazed and two free-grazed paddocks, each of two acres. Feed intake and digestibility were estimated by the chromic-oxide faecal-nitrogen method.2. There was no significant difference in average feed digestibility between the treatments. Free grazing cows ate 30·4 lb. dry matter per day and strip grazing cows 28·9 lb. The difference was just significant (p<0·05). There was no significant difference in milk yield, live-weight or live-weight gain per cow.3. Total feed output per acre was 11% greater on strip grazing when measured by utilised starch equivalent but only 1 % greater when measured by estimated feed consumption. The data suggest that strip-grazed cattle needed less energy for grazing.4. The results are discussed with reference to their accuracy, their implications on grazing management and their correspondence with estimates of food requirements based on indoor feeding standards.

The effect of age and live-weight on the feed intake of grazing wether sheep

1965 ◽  
Vol 7 (3) ◽  
pp. 309-317 ◽  
Author(s):  
G. Hadjipieris ◽  
G. W. Jones ◽  
W. Holmes
Keyword(s):  
Feed Intake ◽  
Dry Matter ◽  
Age Groups ◽  
Live Weight ◽  
Published Data ◽  
Voluntary Feed Intake ◽  
Digestible Organic Matter ◽  
Faecal Nitrogen ◽  
Effect Of Age ◽  
Clover Pasture

SUMMARY1. Estimates of the voluntary feed intake of three age groups of wether sheep on ryegrass and white clover pasture from July to October, 1962, were made by total collection of faeces and the use of local faecal nitrogen-digestibility regressions.2. Average faecal output and intake of digestible organic matter (DOM) increased with age of the sheep. However, relative to body weight (W) or to W073, the aged sheep (5 years old), which did not change much in weight over the period, consumed only about two-thirds of the DOM consumed by the younger (sixteen- and four-month-old) growing sheep.3. For the growing sheep intake was directly related to weight. Intake was calculated to be 24 W (kg.)–28 ±108 g. DOM per day.4. The results are discussed in relation to the errors in estimation of digestibility. Comparison of the intake estimates with other published data suggests there was a high apparent maintenance requirement. The voluntary feed intakes observed, when expressed as g. dry matter per kg. W0–73, were somewhat higher for young sheep but lower for aged sheep than estimates of previous authors.

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