Agronomy and Crop Sciences Commons^™

Nutritive Value Of Perennial Ryegrass Swards Grazed By Sheep In Autumn In The Uk, J A. Milne, H Dove, A M. Sibbald

IGC Proceedings (1977-2023)

A knowledge of the nutrient supply from grazed herbage for ewes in the autumn in N. Europe is required to predict the consequences for their subsequent reproductive performance. Herbage intake has been found to be positively related to sward height over this period at low sward heights but there is no information over a wider range of heights, on the amounts of non-ammonia nitrogen (NAN) available for absorption in the small intestine nor on the digestion of organic matter in the rumen. Experiments on frozen or artificially dried herbage harvested in the autumn have given variable results for the amounts …

Influence Due Niveau De Fertilization Azotee Sur La Degradabilite De L'Azote De La Fetuque Elevee Recoltee En Vert, P Le Goffe, R Verite, G Lemaire

IGC Proceedings (1977-2023)

Il est connu que la fertilisation azotee ameliore non seule­ment la biomasse produite mais aussi la teneur en azote de la plante; cependant certains auteurs la soup9onnent de reduire le flux d'azote duodenal (Armstrong, 1974). Cette diminution de la valeur azotee reelle pourrait s'expliquer par la baisse des syntheses de proteines microbiennes et/ou !'augmentation de la degradation ruminale des proteines de l'herbe. Dans ce travail, l'effet de 2 niveaux de fertilisation azotee, appliques sur 4 cycles successifs d'une fetuque, sur la degradabilite de l'azote de la plante verte a ete etudie par 3 methodes differentes ; de plus l'incidence du …

Estimation Of The Extent Of Bacterial Contamination In Bag Residues And Its Influence On In Sacco Measurements Of Forage Nitrogen Degradation In Rumen, Brigitte Michalet-Doreau, M Y. Ould-Bah

IGC Proceedings (1977-2023)

The nylon bag technique has been used for many years to explain variations in intake and/or digestibility between forages (Van Keuren and Heinemann, 1962; Demarquilly and Chenost, 1969). More recently, this technique has appeared a relatively simple method to estimate the extent and rate of feeds (particularly protein) degradation in the rumen (Mehrez and Orskov, 1977; Madsen and Hvelplund, 1985). In all these studies, it is implicitely accepted that the nitrogen remaining in bags after a stay of variable duration in the rumen corresponds to non degraded feed nitrogen. However, in recent years, sev­eral authors (Mathers and Aitchison, 1981 with …

Effect Of Forage Conservation Methods On In Sacco Nitrogen Degradability In The Rumen, M Y. Ould Bah, Brigitte Michalet-Doreau

IGC Proceedings (1977-2023)

Harvest and conservation of forages cause physico-chemical changes in plant proteins which have variable effects on their digestion in the rumen (Thomson and Beever, 1980). Studies of in sacco degradation have been made on fresh forages (Le Goffe, 1988), hays (Alvir et al., 1988) and silages (Madsen and Hvelplund, 1985; Nocek and Grant, 1987). However, no trial has concerned both fresh· forage and the corresponding conserved forms. It therefore appeared of interest to study modifications in nitrogen degradation resulting from different conservation methods.

Ruminal Disappearance Of Detergent - Fiber Nitrogen In Alfalfa Stems, M A. Sanderson, W F. Wedin

IGC Proceedings (1977-2023)

Accurate estimates of herbage nitrogen (N) that is rurninally degradable are essential to new systems for estimating rumi­nant protein requirements. It has been suggested (Van Soest and Sniffen, 1984) that partitioning herbage N into neutral (NDFN) and acid (ADFN) detergent soluble and insoluble portions may be used to estimate ruminally degradable and undegradable N. Our objective was to determine the in situ degradability of total N, NDFN, ADFN, and available fiber nitrogen (AFN) in alfalfa stems.

Set Up On Nirs Calibration Populations For Predicting Protein And Net Energy Content In Forage Grasses And Legumes, C Paul

IGC Proceedings (1977-2023)

The performance of Near Infrared Reflectance Spectroscopy (NIRS) depends critically on the sample set used in the cali­bration process (e.g. Hruschka and Norris, 1987; Paul, 1988). In forage quality testing a particular problem exists in that nar­row based sample sets comprising only single botanical species may give equations of limited value under practical conditions. Broad based sample sets may, however, lead to equations with reduced analytical precision as compared to the former. The present work aims at a spectroscopic interpretation and a statistical validation of NIRS equations for protein and energy concentration developed from broad based and narrow based sets …

Comparative Study And Validation Of Three Methods To Estimate Apparent Digestibility Of Forages, A D. Cerda, B H. Manterola, A L. Sirhan

IGC Proceedings (1977-2023)

Laboratory methods for predicting in vivo digestibility are affected by a diversity of factors, giving a high variation in results. It is important that each laboratory standardizes and validates the different methods in order to have confidence in their predictive capacity. The main objective of this study is to quantify the most important factors affecting the methods, to obtain the best predicting equations and to set the ranges where those methods fit better.

Nir Spectroscopy For Forage Analysis, F E. Barton Ii

IGC Proceedings (1977-2023)

Near Infrared Reflectance spectroscopy (NIRS) has been used to measure the composition of forages for over 10 years (Norris et al., 1976). The National NIRS Agricultural Research Network has published their ARS Handbook# 643 Near Infra­red Reflectance Spectroscopy for Forage Analysis to summa­rize the research findings (Marten et al., 1985). This document has become the definitive source for information on how to use NIRS to measure forage quality. With these as a starting point there were two areas which needed major research efforts. The first was certification of NIRS as an Official Method by the Association of Official Analytical Chemists …

Comparison Of Laboratory Methods For Estimating Herbage Digestibility, Francoise Riviere, P Maupetit, G Blanchard

IGC Proceedings (1977-2023)

Forages are an important source of nutrients for ruminants and recently interest has been shown in using forages for a greater proportion of the nutrients in ruminant production. The feeding value of forages mainly depends on their digestible organic matter contents. Feeding of forages to animals is the most accurate method of evaluation but such trials are expens­ive and very slow. Many laboratory procedures have been developped for esti­mating forage nutritive value. Recently, near infrared reflec­tance has been developped to provide a fast and reliable alter­native method. The aim of the study is to compare laboratory methods of forage evaluation …

Determination Of Forage In Vivo Digestibility By Nirs, R Biston, P Dardenne, C Demarquilly

IGC Proceedings (1977-2023)

The forage energetic value determination has always been and remains a important issue. It consists in predicting the Organic Matter Digestibility (OMD). Measuring In Vivo OMD on animals is time and money consuming. To predict OMD in laboratory, different chemical, microbiological and enzymatic methods are used. The articles published on the use of Near InfraRed Spec­trometry (NIRS) indicate that this method can improve OMD determination efficiently (Norris, 1983; Shenk, 1977; Biston, 1981, 1984, 1985, 1988). The research work carried out in the Station de Haute Belgique in collaboration with INRA in Theix, has defined the efficiency of these technics for …

Near Infrared Reflectance Spectroscopy For Estimation Of Digestible Organic Matter Intake And Body Weight Gain, H Lippke, F E. Barton Ii, W R. Ocumpaugh

IGC Proceedings (1977-2023)

High correlations have been reported between data from near infrared reflectance spectroscopy (NIRS) and the protein and fiber contents, as well as the intake and digestibility, of forages (Norris et al., 1976). The finding in some studies that sample sets for calibration and unknown samples should be restricted to relatively narrow populations (Marten et al., 1983) has limited the usefulness of NIRS. However, in experiments with legumes, correlations with NIRS data were almost as good across species as among species (Marten et al., 1984). The experiment reported here was conducted to discover quantitative relationships between NIRS spectra and chemical composition, …

Enzymatic Solubility And Other Analytic Parameters Predicting Digestibility In Grasses Of Middling Food Value, J Silva Colomer, M Zarate, J C. Guevara, C Fransinelli

IGC Proceedings (1977-2023)

For a long time, laboratories techniques have been applied to predict "in vivo" digestibility. Among the biological methods, those basing on rumen fluid are the most used in the nutrition laboratories (Osbourn and Siddons, 1980). These techniques, however, present difficulties as the necessity of maintaining rumen-fistulated donor animals, variations in ruminal activity and high cost. For these reasons, the capacity of enzymatic solubility to predict digestibility has been studied in the last few years in different forages : hays, cereal straws, silages and pellets (Aerts et al., 1977 ; Rivero Yeas, 1985), agri­cultural byproducts (Aerts, 1977; Aguilera and Molina, 1986) …

Use Of Near Infrared Spectroscopy To Assess Nutritional Status Of Cattle Diets On Rangelands, J W. Stuth, E D. Kapes, R K. Lyons

IGC Proceedings (1977-2023)

There are two principal means for assessing the quality of grazing ruminant diets, analysis of extrusa from esophageally fistulated animals or indirect estimates from fecal analysis. Wet chemistry methods are well documented for the former but have proven to be of limited value regarding the latter. It is the purpose of this research to determine the suitability of near infrared spectroscopy (NIRS) for estimating diet crude protein (%) and organic matter digestibility (%) directly from extrusa and indirectly from feces.

Predicting Degradability Of Hay Protein By Chemical Or Enzymatic Methods, Jocelyne Aufrere, Brigitte Michalet-Doreau, Dominique Graviou, R Verite

IGC Proceedings (1977-2023)

The amount of dietary protein which reach the small intes­tine depends on the crude protein content of the feed and the degradability of crude protein in the rumen. The second characteristic is generally in France (Verite et al., 1987) esti­mated from in sacco degradation of the feed protein in the rumen. Simpler and less costly laboratory methods have been developed to predict protein degradability : - Chemical methods involving protein solubility in solvents of differents types, pH and extraction temperatures (Pichard and Van Soest, 1977; Crawford et al., 1978). - Enzymatic methods. Although promising, these methods are at present studied …

Near Infrared Reflectance Spectroscopy As A Universal Forage Evaluation Technique, G C. Marten, W R. Windham

IGC Proceedings (1977-2023)

Near infrared reflectance spectroscopy (NIRS) is a nonconsumptive instrumental method for fast evaluation of the chemical composition, associated quality attributes, and physiological properties of forage plants. Norris et al. (1976) reported that NIRS (scanning mono­chromator instrument) could predict chemical composition, dry matter digestibility, dry matter intake, and digestible energy intake of grass and legume forages fed to sheep. Since then, voluminous evidence has been published that confirms the utility of NIRS for analysis and evaluation of forages and other feedstuffs for essentially any organic constituent or qual­ity attribute that can be quantified with an adequate range of concentration in a …

Near Infrared Reflectance Spectroscopy As An Analytical Tool For World Agriculture, J S. Shenk

IGC Proceedings (1977-2023)

Agriculture produces the food and fiber needed for human existence. In the past 100 years, it becames apparent that nutri­ent content and quantity measurements of feed were necessary in livestock feeding programs. During this 100 year period, scientists developed and refined laboratory reference methods for the industry. However, nutritional evaluation of these products was and still is expensive and time consuming. Near infrared spectroscopy (NIRS) analysis offered the promise of rapid low cost analysis of nutrient composition. This analytical method has the potential to overcome the analytical problems facing world agriculture. First reports of NIRS in the literature occured as …

Monitoring The Nutrition Of Grazing Cattle With Near-Infrared Analysis Of Feces, S W. Coleman, J W. Stuth, J W. Holloway

IGC Proceedings (1977-2023)

The nutrition of grazing animals is difficult to assess because of the difficulty in determining the amount and quality of the ingested forage. Although many techniques have been proposed for sampling the grazed forage, none offer quantitat­ive estimates of diet quality and intake for individual animals in large numbers. The feces excreted by animals contain undigested residues of the diet consumed along with products of animal and microbiological origin. The objective was to determine if near-infrared spectroscopy (NIRS) could be used to developed spectral indices from feces which describe the quantitative and qualitative attributes of the diet over a range …

Prevision De La Valeur Nutritive Des Fourrages Ingeres Sur Parcours Naturels Par Les Ruminants Domestiques Saheliens Et Soudaniens, H Guerin, D Richard, P Lefevre, D Friot, N Mbaye

IGC Proceedings (1977-2023)

Les herbivores domestiques eleves sur Jes parcours naturels saheliens et soudaniens consomment des proportions variables d'especes herbacees annuelles en vegetation pendant 3 a 4 mois puis a l'etat de paille sur pied, ainsi que des feuilles ou des fruits d'especes ligneuses disponibles durant toute l'annee. L'objectif de l'etude est d'etablir des equations de previsions de la digesti­bilite de la matiere organique (DMO) ou de la teneur en matieres azotees digestibles (MAD) de ces fourrages en fonc­tion de leur composition chimique ou de celle des feces des ani­maux qui Jes consomment.

Predicting Organic Matter Digestibility Of Forage By Two Pepsin-Cellulase Methods, Jocelyne Aufrere, C Demarquilly

IGC Proceedings (1977-2023)

In vivo organic matter digestibility (OMd) of forage is very variable. That of standing forage varies, depending on species, growth cycle number and more especially stage of development or forage age, between 49 and 86 p. 100 according to the 1 719 samples of grasses, legumes and permanent pastures studied on sheep in our Laboratory (Demarquilly and Andrieu, 1987). Variation may also be caused by conservation method, particu­larly hay-making. Since net energy value depends closely on OMd, a good knowledge of the latter is indispensable in the preparation of animal diets. It is also important in the choice of crop …

Prediction Of The Digestible And Metabolizable Energy Content Of Forages From Their Chemical Composition And Organic Matter Digestibility, J Andrieu, C Demarquilly

IGC Proceedings (1977-2023)

In France, the 'net energy' system (INRA, 1978) permits cal­culation of the net energy (NE) of a feed in an analytical manner: NE = GE x Ed x ME/DE x k

where GE, DE and ME are respectively the gross, digestible and metabolisable energy contents, Ed the energy digestibility and k the net availability of ME for lactation, maintenance or fattening. The publication of Feed Tables (Demarquilly et al., 1978) and their revision (Andrieu et al., 1988) led to re&.earch on whether it is possible to predict the different terms of this formula, at least as far as the ME, …