The principles of animal nutrition

Armsby, Henry Prentiss

doi:10.5962/bhl.title.49667

Cited by 23 publications

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“…Respiration chambers have been used as indirect calorimeters for the measurement of respiratory exchange and CH 4 energy losses of ruminants for more than 120 years (e.g. Armsby, 1903;Kellner, 1913), with numerous publications describing how to construct, calibrate and use them (e.g. Flatt, 1969;Blaxter, 1971;McLean and Tobin, 1988).…”

Section: Respiration Chambers and Enclosuresmentioning

confidence: 99%

Review of current in vivo measurement techniques for quantifying enteric methane emission from ruminants

Hammond

Crompton

Bannink

et al. 2016

Animal Feed Science and Technology

139

117

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Review of current in vivo measurement techniques for quantifying enteric methane emission from ruminants.Animal Feed Science and Technology http://dx.doi.org/10. 1016/j.anifeedsci.2016.05.018 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. techniques based on short-term measurements of gas concentrations in samples of exhaled air. This includes automated head chambers (e.g. the GreenFeed system), the use of carbon dioxide (CO 2 ) as a marker, and (handheld) laser CH 4 detection. Each of the techniques are compared and assessed on their capability and limitations, followed by methodology recommendations. It is concluded that there is no "one size fits all" method for measuring CH 4 emission by individual animals. Ultimately, the decision as to which method to use should be based on the experimental objectives and resources available. However, the need for high throughput methodology e.g. for screening large numbers of animals for genomic studies, does not justify the use of methods that are inaccurate. All CH 4 measurement techniques are subject to experimental variation and random errors. Many sources of variation must be considered when measuring CH 4 concentration in exhaled air samples without a quantitative or at least regular collection rate, or use of a marker to indicate (or adjust) for the proportion of exhaled CH 4 sampled. Consideration of the number and timing of measurements relative to diurnal patterns of CH 4 emission and respiratory exchange are important, as well as consideration of feeding patterns and associated patterns of rumen 4 fermentation rate and other aspects of animal behaviour. Regardless of the method chosen, appropriate calibrations and recovery tests are required for both method establishment and routine operation. Successful and correct use of methods requires careful attention to detail, rigour, and routine self-assessment of the quality of the data they provide.

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Section: Respiration Chambers and Enclosuresmentioning

confidence: 99%

Review of current in vivo measurement techniques for quantifying enteric methane emission from ruminants

Hammond

Crompton

Bannink

et al. 2016

Animal Feed Science and Technology

139

117

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“…The earliest of these consisted of assigning a constant calorific value to the urine/g N although most of the workers concerned realized that this ratio varied with diet (see Armsby, 1908). More recently the heat of combustion of urine has been related to its N content by linear regression methods, which, since they rarely have intercepts of zero, implies that the heat of combustion of urine changes with its N content.…”

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confidence: 99%

“…In some trials, however, the nitrogen content of the urine is determined. Methods are available which enable the methane produced when different diets are given to ruminants in different amounts to be predicted with reasonable precision from knowledge of the faecal loss of energy (Blaxter & Clapperton, 1965) and, if methods were available for estimating the loss of urine energy from commonly measured attributes of the feed, then metabolizable energy could be estimated from the results of trials more simple than complete calorimetric ones.Understandably many attempts have been made to estimate the heat of combustion of ruminant urine from its more easily measured N content. The earliest of these consisted of assigning a constant calorific value to the urine/g N although most of the workers concerned realized that this ratio varied with diet (see Armsby, 1908).…”

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The heat of combustion of the urine of sheep and cattle in relation to its chemical composition and to diet

1966

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I . The results of over 500 determinations of the heat of combustion of the urine produced by cattle and sheep have been analysed statistically. 2. The analytical errors for nitrogen, carbon and heat of combustion were k 0.54, f 1'4 and ? 2.2 %. The error attached to an estimate of the heat of combustion of the urine produced by an individual sheep in 4 days was & 10 %. 3. At the maintenance level of feeding, the heat of combustion of the urine ( U kcal/ 100 kcal food) was related to the crude protein content of the diet (P%) by the equation U = 0.25P+ 1.6, with a residual standard deviation of To.88 kcal/Ioo kcal. 4. Regression analysis of the relation between the heat of combustion of urine and its N content showed significant differences with diet. The heat of combustion of the urine of sheep was 9.7 kcal/g C and of cattle 10.3 kcal/g C, and did not vary with diet. 5. It is shown that the variation in the heat of combustion of urine/g N and its relative constancy/g C arises largely from variation, from diet to diet, in the proportion of the N excreted as hippurate. The metabolizable energy of a feed is its heat of combustion less the heat of combustion of the faeces, urine and combustible gas produced when it is eaten. In many trials with ruminants designed to provide an estimate of the nutritive value of feeds, the measurements made are limited to determinations of the heat of combustion of the feed and the faeces and neither methane nor urine energy are determined. In some trials, however, the nitrogen content of the urine is determined. Methods are available which enable the methane produced when different diets are given to ruminants in different amounts to be predicted with reasonable precision from knowledge of the faecal loss of energy (Blaxter & Clapperton, 1965) and, if methods were available for estimating the loss of urine energy from commonly measured attributes of the feed, then metabolizable energy could be estimated from the results of trials more simple than complete calorimetric ones.Understandably many attempts have been made to estimate the heat of combustion of ruminant urine from its more easily measured N content. The earliest of these consisted of assigning a constant calorific value to the urine/g N although most of the workers concerned realized that this ratio varied with diet (see Armsby, 1908). More recently the heat of combustion of urine has been related to its N content by linear regression methods, which, since they rarely have intercepts of zero, implies that the heat of combustion of urine changes with its N content. Thus Paladines, Reid, Van Niekerk & Bensadoun (1964) Other less satisfactory approaches have been made. Thus both Elliot & Loosli (1959) with cattle and Street, Butcher & Harris (1964) with sheep and cattle have related the heat of combustion of urine/unit weight to its N content/unit weight. Both found positive intercepts for their regressions. This approach implies that the heat of combustion of the urine produced by an animal in a day is greater when it is s...

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“…An example of this is the adiabatic heat flow calorimeter built by Armsby andFries in 1903 (Blaxter, 1962). Another method of direct calo rimetry is the gradient layer calorimeter developed by Benzinger in 1949.…”

Section: Calorimatric Methodsmentioning

confidence: 99%

Energy evaluation of protein sources for young swine

Tegbe

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INFORMATION TO USERSThis materia! was produced from a microfilm copy of the original document. While the most advanced technological means to photograph and reproduce this document have been used, the quality is heavily dependent upon the quality of the original submitted.The following explanation of techniques is provided to help you understand markings or patterns which may appear on this reproduction.

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The principles of animal nutrition

Cited by 23 publications

References 0 publications

Review of current in vivo measurement techniques for quantifying enteric methane emission from ruminants

Review of current in vivo measurement techniques for quantifying enteric methane emission from ruminants

The heat of combustion of the urine of sheep and cattle in relation to its chemical composition and to diet

Energy evaluation of protein sources for young swine

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