The indirect estimation of the digestibility of pasture herbage I. Nitrogen and chromogen as faecal index substances

1960 ◽  
Vol 55 (3) ◽  
pp. 371-376 ◽  
Author(s):  
J. F. D. Greenhalgh ◽  
J. L. Corbett
Keyword(s):  
Organic Matter ◽  
Nitrogen Concentration ◽  
Regression Equation ◽  
Seasonal Differences ◽  
Indirect Estimation ◽  
Faecal Nitrogen ◽  
Standard Deviations ◽  
The Difference ◽  
The Relationship ◽  
Single Regression

1. In seventeen digestibility trials carried out between May and November, 1957, groups of three steers were fed on fresh herbage, cut mainly from mixed swards. Herbage digestibility and the concentrations in faeces of the index substances nitrogen and chromogen were measured over periods of 5 days. Organic matter digestibility ranged from 61·2 to 78·9%.2. The relationship between herbage digestibility and faecal nitrogen concentration could not be described satisfactorily by a single regression equation for all trials, and separate equations were calculated for (a) first-growth herbage and (b) aftermath (second and third growths). For a given faecal nitrogen concentration herbage digestibility was about five units higher for first-growth than for aftermath herbage.3. For the faecalchromogen-digestibilityrelationship the difference between growths was even greater and, again, two equations were required. In most trials the quantity of chromogen excreted was apparently greater than the quantity consumed.4. The ‘seasonal’ differences in faecal index relationships were caused by the fact that later growths of herbage contained considerably greater concentrations of nitrogen and chromogen than did firstgrowth herbage of the same digestibility. There was also some evidence that the relationships may be affected by the application of nitrogenous fertilizers to the sward.5. In order to avoid biases in the indirect estimation of herbage digestibility it appears important to use different regressions for different growths. Although such regressions would be restricted in their application they are likely to be more precise than general equations. In these trials both nitrogen and chromogen regressions had low residual standard deviations of ± 1·5 units of digestibility.

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.

The indirect estimation of the digestibility of pasture herbage III. Regressions of digestibility on faecal nitrogen concentration: effects of species and individuality of animal and of the method of determining digestibility upon the relationships

1963 ◽  
Vol 61 (2) ◽  
pp. 221-226 ◽  
Author(s):  
J. P. Langlands ◽  
J. L. Corbett ◽  
I. McDonald
Keyword(s):  
Organic Matter ◽  
Dry Matter ◽  
Nitrogen Concentration ◽  
Regression Coefficients ◽  
Regression Equations ◽  
Concentration Effects ◽  
Animal Data ◽  
Faecal Nitrogen ◽  
Relationship Of ◽  
The Relationship

1. A 36-day continuous digestibility trial with three steers and three sheep fed fresh pasture herbage was carried out during May and June, 1960. For all animals the digestibilities of herbage organic matter (O.m.) were estimated both by collection of faeces and by administering standard quantities of chromium sesquioxide (Cr203) twice daily and determining concentrations of Cr203 in faeces. In a further 36-day trial during August and September 1960, three steers and three cows were used; with the steers, digestibilities were estimated by both methods but with the cows by the Cr203 method only.2. Regression equations were obtained relating O.m. digestibility to the percentage of nitrogen (N) in faecal O.m. When digestibilities were estimated by the same method the same regression coefficients could be fitted to the data from each of the steers and sheep in the spring trial. A similar result was found with the data from each of the steers and cows in the summer trial.3. In each equation different constant terms were required for each animal, which differed significantly between individuals but not between species or class of animal. Data obtained from an examination of the relationship of g. N excreted per 100 g. feed dry matter to g. N intake per 100 g. feed dry matter indicated that differences between the constant terms could be linked with variations between animals in the excretion of metabolic faecal N.

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 indirect estimation of the digestibility of pasture herbage. IV. Regressions of digestibility on faecal nitrogen concentration: effects of different fractions of the herbage upon within- and between-period regressions

1966 ◽  
Vol 66 (2) ◽  
pp. 277-283 ◽  
Author(s):  
J. F. D. Greenhalgh ◽  
G. W. Reid ◽  
I. McDonald
Keyword(s):  
Nitrogen Concentration ◽  
Concentration Effects ◽  
Indirect Estimation ◽  
Usual Manner ◽  
Faecal Nitrogen ◽  
Time Of Year

1. In each of 6 digestibility trials, comprising a total of 21 measurement periods of 3-4 days, two steers were fed on herbage cut from the top of the sward, two on the remaining bottom growth and two on a mixture of equal parts of these fractions. Within each period the fractions were similar in digestibility although the top growth had a higher content of nitrogen.2. The trials were divided into three groups, according to time of year, for the purpose of calculating regressions of digestibility on faecal nitrogen concentration. Regressions calculated in the usual manner on a between-period basis (i.e. within animals) had constant terms which differed significantly among animals but not from one fraction of the herbage to another.

Faecal index to estimate intake and digestibility in grazing sheep

2013 ◽  
Vol 152 (4) ◽  
pp. 667-674 ◽  
Author(s):  
D. B. DAVID ◽  
C. H. E. C. POLI ◽  
J. V. SAVIAN ◽  
G. A. AMARAL ◽  
E. B. AZEVEDO ◽  
...  
Keyword(s):  
Organic Matter ◽  
Linear Equation ◽  
Crude Protein ◽  
Live Weight ◽  
Regression Equations ◽  
Multiple Model ◽  
Sheep Grazing ◽  
Acid Detergent Fibre ◽  
The Difference ◽  
The Relationship

SUMMARYThe current research was carried out to evaluate the use of crude protein and fibre components in faeces for estimating intake and digestibility in sheep fed with pearl millet (Pennisetum americanum (L.) Leeke). The equations were developed from four trials in metabolism cages with 16 sheep in each trial. Each animal received a different quantity of millet leaves in the diet: 0·015, 0·020 and 0·025 dry matter (DM) as a proportion of live weight (LW) and ad libitum with at least 0·2 of daily feed refusals. Organic matter intake (OMI, g/day) was measured, through the difference between offer and refusals; total faeces were collected for 5 days, which was used to determine faecal crude protein (CPf, g/day and g/kg of organic matter (OM)), faecal neutral detergent fibre (NDFf, g/day and g/kg OM), faecal acid detergent fibre (ADFf, g/day and g/kg OM) and OM digestibility (OMD). Linear regression equations were calculated to determine the relationship between OMI and CPf (P<0·001, R2=0·90, relative prediction error (RPE=14·02%). A multiple linear equation was generated for OMI including CPf and NDFf (P<0·001, R2=0·94; RPE=9·25%). Hyperbolic (single and multiple) and exponential models were tested to estimate OMD, where the hyperbolic multiple model including CPf and NDFf showed lower RPE (3·90%). These equations for estimating OMI and OMD were evaluated on sheep grazing P. americanum fertilized with increasing levels of nitrogen (N) (50, 100, 200 and 400 kg N/ha), comparing measured and estimated OMI. The intake estimated by multiple regression (CP and NDFf) showed a higher R2 (0·98) and lower RPE (5·25%) than the simple (CPf only) linear equation (R2=0·94; RPE=20·45%). The results demonstrated the feasibility of using the faecal index generated in metabolism cages for estimating intake and digestibility in sheep grazing P. americanum.

scholarly journals Sedimentary supply of humic-like fluorescent dissolved organic matter and its implication for chemoautotrophic microbial activity in the Izu-Ogasawara Trench

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Shigemitsu ◽  
T. Yokokawa ◽  
H. Uchida ◽  
S. Kawagucci ◽  
A. Murata
Keyword(s):  
Organic Matter ◽  
Community Structure ◽  
Dissolved Organic Matter ◽  
Oxygen Utilization ◽  
Fluorescent Dissolved Organic Matter ◽  
Vertical Distributions ◽  
The Difference ◽  
The Relationship ◽  
Apparent Oxygen Utilization

AbstractMicrobial community structure in the hadal water is reported to be different from that in the upper abyssal water. However, the mechanism governing the difference has not been fully understood. In this study, we investigate the vertical distributions of humic-like fluorescent dissolved organic matter (FDOMH), chemoautotrophic production, apparent oxygen utilization (AOU), and N* in the Izu-Ogasawara Trench. In the upper abyssal waters (< 6000 m), FDOMH has a significantly positive correlation with AOU; FDOMH deviates from the relationship and increases with depth without involving the increment of AOU in the hadal waters. This suggests that FDOMH is transferred from the sediments to the hadal waters through pore water, while the FDOMH is produced in situ in the upper abyssal waters. Chemoautotrophic production and N* increases and decreases with depth in the hadal waters, respectively. This corroborates the effluxes of dissolved substances, including dissolved organic matter and electron donors from sediments, which fuels the heterotrophic/chemoautotrophic microbial communities in the hadal waters. A simple box model analysis reveals that the funnel-like trench topography facilitates the increase in dissolved substances with depth in the hadal waters, which might contribute to the unique microbiological community structure in these waters.

A note on the relationship between milk yield and reproductive performance in some British Friesian sire progeny groups

1982 ◽  
Vol 34 (2) ◽  
pp. 239-241
Author(s):  
P. D. P. Wood ◽  
J. P. Frappell
Keyword(s):  
Milk Yield ◽  
Reproductive Performance ◽  
Standard Error ◽  
Standard Deviations ◽  
The Difference ◽  
The Relationship

ABSTRACTThe 305-day lactation milk yields and the numbers of inseminations required to obtain a pregnancy during a particular lactation were obtained from 1475 lactations of 808 daughters of eight bulls, whose Improved Contemporary Comparisons spanned two genetic standard deviations of milk yield. All lactations were completed before September 1978. Cattle requiring more than one insemination for a pregnancy produced 173 (standard error of difference = 55) kg more milk in 305 days than those requiring only one. There was no correlation between the Improved Contemporary Comparisons of the sire and either the difference in yield, or the proportion of animals needing one or those needing more than one insemination per pregnancy.

scholarly journals Bilingual Education and English Proficiency

2010 ◽  
Vol 5 (2) ◽  
pp. 200-227 ◽  
Author(s):  
Christopher Jepsen
Keyword(s):  
Bilingual Education ◽  
English Learners ◽  
Fixed Effects ◽  
Regression Models ◽  
English Proficiency ◽  
Value Added ◽  
Ordinary Least Squares ◽  
Standard Deviations ◽  
The Difference ◽  
The Relationship

In 2001, California instituted a statewide test measuring English proficiency for English learners, students who are not proficient in English. In 2003 and 2004, nearly 500,000 English learners in grades 1–5 took this test each year. The relationship between bilingual education receipt and English proficiency is estimated using value-added regression models for each section of the test—listening and speaking, reading, and writing. In these regression models, students in bilingual education have substantially lower English proficiency of 0.3 standard deviations or more compared with other English learners in first and second grades. In contrast, the difference between bilingual education and other programs is usually less than 0.1 standard deviations for students in grades 3–5. These results hold for ordinary least squares, school fixed effects, and propensity score models.

Wool growth of pregnant and lactating Merino ewes

1985 ◽  
Vol 105 (3) ◽  
pp. 613-622 ◽  
Author(s):  
V. H. Oddy
Keyword(s):  
Organic Matter ◽  
Fibre Diameter ◽  
Wool Fibre ◽  
Total Plasma ◽  
Wool Growth ◽  
Digestible Organic Matter ◽  
Pregnancy And Lactation ◽  
The Difference ◽  
The Relationship ◽  
Growth Deficit

SUMMARYThe wool production of pregnant, lactating and non-pregnant, non-lactating (dry) Merino ewes eating one of three diets: chaffed oaten hay (OH), chaffed lucerne hay (LH), and a 50/50 (w/w) mixture of OH and LH, was determined. Measurements were made for 2 months prior to mating, during pregnancy and for 3 months after lambing, and for the dry ewes over the same period.Production of clean wool (Y, g/day) by dry ewes was linearly related to digestible organic matter intake (X, g/day):Y = 0·0301 X - 3·34, r = 0·97.Clean wool growth was significantly less (P < 0·01) than dry ewes in the 4th and 5th month of pregnancy and throughout lactation. During pregnancy the total deficit in clean wool growth (calculated as the difference between observed wool growth and that expected on the basis of the relationship between feed intake and clean wool growth of dry ewes) was 456 g for ewes bearing a single lamb and 578 g for those bearing twins, with no difference between diets. In lactation the total clean wool growth deficit increased as milk production increased, and for every litre of milk produced there was a deficit of 12 g clean wool.Wool fibre diameter was reduced during the 1st month of lactation. There was no consistent effect of pregnancy or lactation on the number of wool follicles per mm2, the ratio of primary plus secondary to primary wool follicles, or on the thickness of skin on the midside.Digestibility of dietary organic matter (DOM) was reduced during the last 3 months of pregnancy, and the first 2 months of lactation. However, this was insufficient to account for the magnitude of the decrease in wool growth seen during pregnancy and lactation.Wool sulphur content increased during pregnancy (P < 0·001), but not during lactation. The relationship between total plasma cyst(e)ine concentration and DOM intake during pregnancy was similar to that in dry ewes, but during lactation total plasma cyst(e)ine concentration was less than expected. It was calculated that during pregnancy the amount of sulphur saved through reduced wool growth was greater than that deposited in the conceptus, and during lactation the amount of sulphur saved in reduced wool growth matched that excreted as milk.These results are discussed in relation to control of wool growth during pregnancy and lactation.

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.

Sign in / Sign up

Export Citation Format

Share Document