131 research outputs found
Plasma natural 15N abundance may predict both feed conversion efficiency and residual feed intake in beef cattle across different dietary conditions
Cheap and rapid methods to predict between-animal variability of feed efficiency (FE) areneeded. We evaluated, by using a large dataset on beef cattle (n = 355) fed contrasting diets(grass vs corn based diets), the potential of plasma natural 15N abundance (δ15N) as abiomarker of between-animal variation in FE, measured either as feed conversion efficiency(FCE) or residual feed intake (RFI). Data were analyzed by mixed models, with diet and δ15Nas a fixed effect and experimental farm, batch and pen as random effects. A negative andsignificant correlation was found between FCE and δ15N within each contemporary group,with a lower response (slope) however in grass vs corn diets (δ15N × diet interaction; P =0.002). Likewise, we found a significant but positive relationship between δ15N and RFI, butwithout the influence of diet or any tested random effect. Our results indicate that δ15N is apromising biomarker of between-animal variation of feed efficiency (FCE and RFI) ingrowing beef cattle
Identifying cattle with superior growth feed efficiency through their natural <sup>15</sup>N abundance and plasma urea concentration: A meta-analysis
Mécanismes digestifs et métaboliques associés aux différences inter-individuelles de l’efficience alimentaire chez le bovin allaitant
Comprendre les mécanismes à l’origine des phénotypes d’intérêt en production animale est capital pour la sélection et l’alimentation des animaux. Dans le cadre du programme BEEFALIM 2020, qui visait à améliorer l’efficience alimentaire chez le bovin allaitant, plusieurs expériences ont été menées pour étudier les mécanismes digestifs et métaboliques associés aux variations individuelles de l’efficience alimentaire chez des jeunes bovins, génisses et vaches de race Charolaise. Pour évaluer les mécanismes digestifs et métaboliques impliqués, nous avons couplé des mesures directes à l’aide des méthodes de référence et des mesures indirectes à l’aide d’indicateurs (proxies et biomarqueurs). L’efficience alimentaire était caractérisée par la consommation moyenne journalière résiduelle, définie comme la partie de l’ingestion de matière sèche mesurée qui n’est pas expliquée par les performances animales observées (poids vif, gain de poids et composition du gain). Les résultats obtenus confirment que certains mécanismes d’ordre métabolique, ainsi que la composition corporelle des animaux, seraient associés de façon plus forte aux variations individuelles d’efficience alimentaire que les mécanismes d’ordre digestif, surtout lorsque les régimes sont riches en amidon. Un renouvellement des protéines tissulaires plus lent semble expliquer le meilleur taux de conversion de l’azote alimentaire en muscle chez les animaux efficients alimentés avec des régimes riches en amidon. Cependant, notre dispositif expérimental ne nous permet pas d’exclure la possibilité que l’appétit ou la capacité d’ingestion des animaux contribuent aux différences d’efficience alimentaire entre individus. En effet, les mécanismes identifiés pourraient être associés au phénotype efficient uniquement parce qu’ils covarient avec le niveau d’ingestion. D’après les résultats de cette étude et ceux de la littérature, il est suggéré néanmoins que le métabolisme et en particulier le renouvellement protéique seraient associés aux variations d’efficience alimentaire de manière indépendante du niveau d’ingestion. Ils constitueraient une première piste pour les considérer comme de vrais déterminants du phénotype d’efficience alimentaire. Des études complémentaires sont nécessaires pour établir le lien de causalité entre les mécanismes identifiés et l’efficience alimentaire
Contribution of nutrient fluxes to the evolution of the net energy systems, example of the INRA feeding system for beef cattle
Contribution of nutrient fluxes to the evolution of the net energy systems, example of the INRA feeding system for beef cattl
Conception and development of a bibliographic database of blood nutrient fluxes across organs and tissues in ruminants: data gathering and management prior to meta-analysis
In the organism, nutrient exchanges among tissues and
organs are subject to numerous sources of physiological or nutritional
variation, and the contribution of individual factors needs to be quantified
before establishing general response laws. To achieve this, meta-analysis of
data from publications is a useful tool. The objective of this work was to
develop a bibliographic database of nutrient fluxes across organs and
tissues of ruminant animals (Flora) under Access using the Merise method.
The most important criteria for Flora were the ease to relate the various
information, the exhaustivity and the accuracy of the data input, a complete
description of the diets, taking into account the methods of the
methodological procedures of measurement and analysis of blood nutrients and
the traceability of the information. The conceptual data model was built in
6 parts. The first part describes the authors and source of publication, and
the person in charge of data input. It clearly separates and identifies the
experiments, the groups of animals and the treatments within a publication.
The second part is concerned with feeds, diets and their chemical
composition and nutritional value. The third and fourth parts describe the
infusion of any substrates and the methods employed, respectively. The fifth
part is devoted to the results of blood flows and nutrient fluxes. The sixth
part gathers miscellaneous experimental information. All these parts are
inter-connected. To model this database, the Merise method was utilised and
26 entities and 32 relationships were created. At the physical level, 93
tables were created, corresponding, for the majority, to entities and
relationships of the data model. They were divided into reference tables
() and data tables (). Data processing was developed in Flora and
included the control of the data, generic calculations of unknown data from
given data, the automation of the estimation of the missing data or the
chemical composition of the diets. It also included the construction of
tables for meta-analyses and the study of the variations of several factors
within publications (pre-coding of meta-analyses). Overall, the system was
built to facilitate the gathering, input, validation, management and
retrieval of data from publications
Réponses des tissus splanchniques des ruminants à des changements de niveau d'alimentation : Absorption de produits terminaux de la digestion, masse des tissus, activité métabolique et implications pour le métabolisme énergétique de l'animal entier
International audienc
Whole-body fuel selection in ruminants : nutrient supply and utilization by major tissues
Digesta flows in sheep fed poor-quality hay supplemented with urea and carbohydrates
Two metabolism trials were conducted with 12 yearling crossbred wethers per trial (34 and 38 kg for trials 1 and 2, respectively). The wethers, equipped with ruminal, abomasal and ileal cannulae, were randomly allotted for each trial to the following treatments: 1) hay alone or hay supplemented with 2) .9% urea, 3) 1% urea and 6.5% molasses or 4) 1% urea and 5.2% corn. Two digestive flow markers were used: Cr2O3 powder and Co-ethylenediaminetetraacetic acid (Co-EDTA). Urea and Co-EDTA were infused continuously into the rumen via cannula. Daily dry matter (DM) intake averaged 517 g. Urea supplementation improved N retention (P less than .01). Apparent digestibility of DM, acid detergent fiber (ADF) and energy was not affected by treatment. Urea and carbohydrate supplementation increased ruminal propionic acid molar proportions (P less than .05). Apparent ruminal DM digestion accounted for 41% of the total DM degraded, whereas 77.4% of the digestible ADF was degraded in the rumen. Urea supplementation increased ADF digestion in the large intestine (P less than .01). Urea and carbohydrate supplementation resulted in a stepwise increase in N flowing with the liquid phase at the abomasum. Mean retention times of the solid and liquid phases of digestive contents were similar across treatments. Overall, benefits of supplementation of poor-quality fescue hay diets by small amounts of urea and readily available carbohydrates remain questionable for sheep fed at a fixed level of intake below maintenance
Conception and development of a bibliographic database of blood nutrient fluxes across organs and tissues in ruminants: data gathering and management prior to meta-analysis
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