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International audience; Ruminant feed utilisation efficiency is determined in part by organic matter digestibility (OMD). However, OMDis expensive and time consuming to measure it in routine. Faecal near infrared (faecal-NIR) spectroscopy has beendeveloped for predicting OMD in cattle across, but its potential for estimating the between-animal variability ofOMD has not been reported. The objective of this study was to evaluate the use of of faecal-NIR for assessing thebetween-animal variability of OMD across different dietary and experimental conditions in cattle. Faecal samplesfrom individual beef and dairy cows associated (n=454) to individual measured OMD values were used. Valuesranged from 55.1 and 85.0% (mean±SD; 70.6±4.20%) for 9 experiments at 4 EU sites using 50 different diets. ANIR calibration model for predicting OMD was obtained and validated by cross-validation. Relationship betweencross-validated OMD predictions and measured OMD values were analysed by regression analysis with faecal-NIRcross-validated predictions as fixed factor and diet within experiment as random factor. The faecal-NIR predictionwas positive and correlated (P

Multiblock PLS-DA on fecal and plasma visible-near-infrared spectra for discriminating young bulls according to their efficiency. Preliminary results. Conférence Chimiométrie 2020

The objective of this study was to evaluate the effect of tree occurrence and density on grass yield, phenological stage (SMP), and nutritional value during the second grassland growth cycle. Three plots with different tree densities (0, 60, and 150 trees/ha) were used. Plots were sampled every 15 days between July 25 and October 27, 2017 The plots did not differ in grass yield, SMP, chemical composition (ie., various measures), or nutritional value. No differences between data sampling were found for yield, smp, and cell wall content. Furthermore, tree occurrence had no effect on grass nutritional value across the second growth cycle.

Session 45 - Théâtre 14; Diet digestibility and intake are animal traits difficult to measure in practice. Thus, several indirect methods including faecal visible/near infrared (VIS/NIR) spectroscopy, have been developed for predicting these traits. The development of this technology requires great number of samples, which are not always obtained in standardized conditions among experiments. Consequently, the lack of standardization could be associated to a loss of precision of VIS/NIR models. In order to test this hypothesis, we used 88 VIS/NIR spectra of faeces sampled on cattle beef and dairy cows from 3 different experiments (De la Torre et al., 2019; Herremans et al., 2019; Fanchone et al., 2013). Experiments included measurements of the individual organic matter digestibility (OMD) and daily dry matter intake (DI) of animals. Two calibration strategies were compared for predicting these measurements: (1) specific experiment calibration and (2) a global calibration procedure. Models were assessed by standard error of cross-validation (SECV) and coefficient of determination of cross-validation (R2CV). The SECV was separated into bias and SECV corrected by bias SECV(C). Bias and SECV(C) for both calibration strategies were compared using the procedure of Fearn (1996). Data sets gave value ranges of 0.60-0.78 for OMD and 53-181 g/kg body weight (BW)0.75 for DI. For OMD, the SECV and R2CV were 0.02 and 0.86 for both specific experiment calibration and global calibration procedure. For DI, the SECV and R2CV were 6.90 g/kg BW0.75 and 0.96 respectively, for the specific experiment calibration and 7.62 g/kg BW0.75 and 0.95, respectively, for the global calibration procedure. For both, OMD and DI, no significant differences between calibration strategies were found for bias and SECV(C). From the results of this preliminary study, we conclude that mixing data from experiments conducted in very different conditions does not degrade the precision of the obtained VIS/NIRS models to predict OMD and DI in cattle.

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National audience

International audience; Sainfoin (Onobrychis viciifolia) is a temperate legume that contains condensed tannins (CT), i.e., polyphenols that are able to bind proteins and thus reduce protein degradation in the rumen. Few studies have investigated the relation between plant phenology, CT characteristics and nutritive value of sainfoin. In this study we investigated differences among three sainfoin varieties (Esparcette, Ambra and Villahoz) that were of different geographical origin, and which were cultivated at the same site over the course of two growth cycles and compared with a tannin-free legume, lucerne (Aubigny). Plants were harvested on nine dates in the first and four dates in the second growth cycle. Phenological stages were analysed for leaf-to-whole-plant ratio, nitrogen (N), organic matter digestibility (OMd) by the pepsin-cellulase method, cell-wall concentration, N solubility (solN) plus CT concentration, biological activity and structures. Leaf-to-whole-plant, cell-wall concentration, N of sainfoin and lucerne were closely related to the phenological stage. Although sainfoin developed earlier than lucerne, its pepsin-cellulase digestibility was higher than or close to lucerne. Esparcette had the lowest OMd, N and solN and the highest CT concentration. CT concentration, proportion of prodelphinidins (PD) and mean degree of polymerization (mDP) increased with the phenological stage (or plant maturity), and these parameters were associated with lower biological activity of CT. Sainfoin varieties differed in their relationships between phenological stages, nutritional parameters and CT characteristics. The results demonstrated that sainfoin can be a valuable alternative forage legume to lucerne.

National audience

International audience; The development of rapid analytical methods for diet authentication and quality assessments in animal products is under active investigation. We assessed the ability of visible spectroscopy to distinguish pasture-fed (P) from stall concentrate-fed (S) lamb carcasses using a large database totalling 1054 (418 P and 636 S) male lambs from three sheep breeds, i.e. 148 P and 258 S Romane breed, 102 P and 92 S Ile-de-France breed, and 168 P and 286 S Limousine breed lambs. The reflectance spectrum of perirenal fat was measured 24 h postmortem at wavelengths between 400 and 700 nm using a portable spectrophotometer. We quantified light absorption by carotenoids in the 450-510 nm area (method 1, M1) and performed a multivariate analysis over the full set of reflectance data (method 2, M2). Using M1, the proportion of correctly-classified S lambs was 100%, 95.8% and 93.5% in Romane, Limousine and Ile-de-France breeds, respectively, while the proportion of correctly-classified P lambs was 87.2%, 81.5% and 66.7% in Romane, Limousine and Ile-de-France breeds, respectively. Using M2, the proportion of correctly-classified S lambs was 99.6%, 99.6% and 97.9% in Romane, Limousine and Ile-de-France breeds, respectively, while the proportion of correctly-classified P lambs was 89.9%, 85.7% and 92.2% in Romane, Limousine and Ile-de- France breeds, respectively.

Colloque Dinabio mai 2008 à Montpellier; National audience; The ‘organic’ label on a product guarantees that synthetic fertilisers, pesticides and hormones are not used in the production process and that the use of pharmaceutical products and drugs is limited.However,product quality is often questioned and we have to anticipate the consumer demand for product quality guarantees. This study was conducted to compare the sensory and nutritional meat and carcass qualities of lambs raised under an organic (O) or a conventional (C) production system. Comparisons were made with both pasture-fed lambs and lambs that were stall-fed indoors with concentrate and hay. The experiment was conducted over two years for stall-fed lambs (S) (group O, n=24; group C, n=24) and three years for pasture-fed lambs (P) (group O, n=36; group C, n=36). For P lambs, O and C production systems differed in terms of the level of mineral N fertilisation of the pasture.; Cette étude a comparé les qualités de la viande et de la carcasse d’agneaux produits en élevage biologique (AB) ou conventionnel (C). L’expérimentation a été conduite pendant 2 ans pour les agneaux de bergerie (B) (lot AB n=24 ; lot C n=24), et 3 ans pour les agneaux d’herbe (H) (lot AB n=36 ; lot C n=36). Pour les agneaux H, les modes de production AB et C différaient par le niveau de fertilisation minérale sur la prairie; pour les agneaux B, les aliments étaient issus de l’agriculture soit biologique, soit conventionnelle, les concentrés AB et C étant constitués des mêmes matières premières. Pour les agneaux de bergerie, le mode de production AB comparé à C a amélioré la valeur santé des acides gras (AG) de la viande pour l’homme, sans différences pour les qualités bouchères et sensorielles de la viande et de la carcasse. Pour les agneaux d’herbe, la valeur santé des AG déposés dans la viande a été similaire entre AB et C; cependant, les côtelettes AB ont présenté une odeur anormale de leur gras plus élevée que les côtelettes C, résultat probablement dû à une proportion plus importante de trèfle blanc dans la ration.

International audience