Husbandry factors and health conditions influencing the productivity of French rabbit farms

[EN] In 2009 productivity data from 95 kindling to finishing rabbit farms in France were analysed to identify rearing factors and health conditions that influenced their productivity. Farm productivity, expressed on a yearly basis, was described with 4 productivity indices: doe fertility and prolificacy, viability of young rabbits in the nest and mortality during the fattening period. The productivity data were obtained with the technical support of the farm and expressed in a standardised way. The average numerical productivity observed in the sample of farms was 50.9 rabbits produced per doe and per year (CI95% [49.6-52.2]). The husbandry management and health conditions were described based on a questionnaire filled out during an interview with the farmer and a farm visit. Explanatory data were organised into meaningful blocks relative to biosecurity measures, del using a Partiamaternity management, the sanitary context and the farm structure. The relationship between the 4 thematic blocks and the productivity indices was studied in a single mol Least Squares (PLS) regression model. Fertility (81.0%, CI95% [80.0-82.0]) and viability of young at nest (85.1%, CI95% [85.0-85.3] and mortality rate during fattening: 7.2%, CI95% [6.4-7.9]) were significantly associated with common factors relative to maternity management and the health context whereas prolificacy (9.7 live kits per parturition, CI95% [9.5-9.9]) was mostly influenced by a specific set of variables pertaining to those 2 blocks. Farm structure and biosecurity measures had a limited impact on fertility and on kit viability before weaning. The health conditions of the doe herd and the fattening rabbits were found to be significantly associated with several productivity indexes, but their impacts on productivity were as high as the impact of the other blocks. Genetic strain of the females, doe replacement strategy and nursing and weaning practices appeared to significantly influence reproductive performance, viability of kits before weaning and mortality rate during the fattening period. Maternity management therefore seemed to be the key point in rabbit unit management that governed the numerical productivity of the farm.The authors wish to acknowledge the CLIPP-Lapin de France, the SNGTV (French Veterinary Society - rabbit branch) and the FFC (French Federation of Cuniculture) for their collaboration. We also wish to thank the farmers and the rabbit production organisations who participated in the study. The authors are grateful to Ms. Anaïs Croisier for her participation as an investigator and to Mr. Guillaume Coutelet from the French Institute for Avian Production for his technical expertise. Funding was provided by the French Agency for Veterinary Medicinal Products (ANSES-ANMV)Huneau-Salaün, A.; Bougeard, S.; Balaine, L.; Eono, F.; Le Bouquin, S.; Chauvin, C. (2015). Husbandry factors and health conditions influencing the productivity of French rabbit farms. World Rabbit Science. 23(1):27-37. https://doi.org/10.4995/wrs.2015.3076SWORD2737231Castellini, C., Dal Bosco, A., Arias-Álvarez, M., Lorenzo, P. L., Cardinali, R., & Rebollar, P. G. (2010). The main factors affecting the reproductive performance of rabbit does: A review. Animal Reproduction Science, 122(3-4), 174-182. doi:10.1016/j.anireprosci.2010.10.003Coutelet G. 2011. Performances moyennes des élevages cunicoles en France pour l'année 2010. Cuniculture Magazine, 38: 24-27.EFSA. 2005. Scientific Opinion of the Scientific Panel on Animal Health and Welfare on the impact of the current housing and husbandry systems on the health and welfare of farmed domestic rabbits. EFSA J., 2005: 1-31.Lebas F. 2010. Situation cunicole en France en 2009: performances moyennes des élevages selon les résultats du RENACEB pour l'année 2009, situation du marché cunicole français et premières évaluations pour l'année 2010. Cuniculture Magazine, 37: 74-82.Licois D., Coudert P., Marlier D. 2006. Epizootic rabbit enteropathy. In: L. Maertens, P. Coudert (ed). Recent advances in rabbit sciences. Institute for Agricultural and Fisheries Research, Melle, Belgium, 163-170.Marongiu M.L., Dimauro C., Floris B. 2007. A six-year investigation on reproductive performance of hybrid rabbits. 1. Pregnancy rate and numerical productivity at weaning as affected by season. Ital. J. Anim. Sci., 6: 770-772.Rommers J., Maertens L., Kemp B. 2006. New perspectives in rearing systems for rabbit does. In: L. Maertens, P. Coudert (ed). Recent advances in rabbit sciences. Institute for Agricultural and Fisheries Research, Melle, Belgium, 39-51.Serrano P., Pascual M., Gómez E.A. 2012. Analysis of management techniques on productivity indicators using the bdcuni Spanish database. In Proc.: 10th World Rabbit Congress, 3-6 September, 2012. Sharm El-Sheikh, Egypt. 1: 803-807

An unusual carbon cycle budget of a small stream in a mountain silicate terrain: The case of the Gravona river (Corsica)

Abstract The current research of carbon cycling in inland waters lacks a sound knowledge of carbon outgassing from small streams. As a consequence, these compartments of the terrestrial water cycle might still be seriously underrepresented in estimates of global carbon transfer budgets from land surfaces. This study investigated carbon sources and sinks of a mountain river in a silicate catchment. For this purpose, the high‐relief Gravona river, in the western part of the island of Corsica (France) in the Western Mediterranean, was investigated for field parameters, dissolved inorganic carbon (DIC) and its stable carbon isotopes (δ13CDIC). The source region was characterized by low DIC contents and high δ13CDIC values that decreased further downstream due to increasing soil respiration. Associated increasing DIC concentrations and elevated seasonality in the lower river section also indicated more respiration and subsequent DIC‐input by weathering. The aqueous partial pressure (pCO2(aq)) was lowest at the source of the Gravona river and samples from the cold season even showed undersaturation that led to uptake of atmospheric CO2. Further downstream, the seasonality of pCO2(aq) increased and was particularly pronounced near the river mouth where CO2 degassing took place. Average DIC flux along the river was 0.129 Gg C year−1 and was almost equal to CO2 degassing from the river surface with 0.128 Gg C year−1. Our study showed that on an annual basis the river is an overall weak to medium source of CO2 to the atmosphere even though headwater parts of the river seasonally act as CO2 sinks

Past millennium hydroclimate variability from Corsican pine tree-ring chronologies

Palaeoclimatic evidence is necessary to place the current warming and drying trends of the Mediterranean region in a long‐term perspective of pre‐industrial variability. Annually resolved and absolutely dated climate proxies that extend back into medieval times are, however, limited to a few sites only. Here we present a network of long ring width chronologies from Pinus nigra tree‐line sites in northern Corsica (France) that cohere exceptionally well over centuries and support the development of a single high‐elevation pine chronology extending back to 974 CE. We apply various detrending methods to these data to retain high‐to‐low frequency ring width variability and scale the resulting chronologies against instrumental precipitation and drought observations to produce hydroclimate reconstructions for the last millennium. Proxy calibration and transfer are challenged by a lack of high‐elevation meteorological data, however, limiting our understanding of precipitation changes in sub‐alpine tree‐line environments. Our new reconstructions extend beyond existing records and provide evidence for low‐frequency precipitation variability in the central‐western Mediterranean from 974–2016 CE. Comparison with a European scale drought reconstruction network shows that regional predictor chronologies are needed to accurately estimate long‐term hydroclimate variability on Corsica

Tritium as a hydrological tracer in Mediterranean precipitation events

Climate models are in need of improved constraints for water vapor transport in the atmosphere, and tritium can serve as a powerful tracer in the hydrological cycle. Although the general principles of tritium distribution and transfer processes within and between the various hydrological compartments are known, variation on short timescales and aspects of altitude dependence are still under debate. To address questions regarding tritium sources, sinks, and transfer processes, the sampling of individual precipitation events in Corte on the island of Corsica in the Mediterranean Sea was performed between April 2017 and April 2018. Tritium concentrations of 46 event samples were compared to their moisture origin and corresponding air mass history. Air mass back-trajectories were generated from the novel high-resolution ERA5 dataset from the ECMWF (European Centre for Medium-Range Weather Forecasts). Geographical source regions with similar tritium concentrations were predefined using generally known tritium distribution patterns, such as the “continental effect”, and from data records derived at long-term measurement stations of tritium in precipitation across the working area. Our model-derived source region tritium concentrations agreed well with annual mean station values. Moisture that originated from continental Europe and the Atlantic Ocean was most distinct regarding tritium concentrations with values up to 8.8 TU (tritium units) and near 0 TU, respectively. The seasonality of tritium values ranged from 1.6 TU in January to 10.1 TU in May, and they exhibited well-known elevated concentrations in spring and early summer due to increased stratosphere–troposphere exchange. However, this pattern was interrupted by extreme events. The average altitude of trajectories was correlated with the tritium concentrations in precipitation, especially in spring and early summer and if outlier values of extreme tritium concentrations were excluded. However, in combination with the trajectory information, these outlier values proved to be valuable for improving the comprehension of tritium movement in the atmosphere. Our work shows how event-based tritium research can advance the understanding of its distribution in the atmosphere

The Nature of the Dietary Protein Impacts the Tissue-to-Diet 15N Discrimination Factors in Laboratory Rats

Due to the existence of isotope effects on some metabolic pathways of amino acid and protein metabolism, animal tissues are 15N-enriched relative to their dietary nitrogen sources and this 15N enrichment varies among different tissues and metabolic pools. The magnitude of the tissue-to-diet discrimination (Δ15N) has also been shown to depend on dietary factors. Since dietary protein sources affect amino acid and protein metabolism, we hypothesized that they would impact this discrimination factor, with selective effects at the tissue level. To test this hypothesis, we investigated in rats the influence of a milk or soy protein-based diet on Δ15N in various nitrogen fractions (urea, protein and non-protein fractions) of blood and tissues, focusing on visceral tissues. Regardless of the diet, the different protein fractions of blood and tissues were generally 15N-enriched relative to their non-protein fraction and to the diet (Δ15N>0), with large variations in the Δ15N between tissue proteins. Δ15N values were markedly lower in tissue proteins of rats fed milk proteins compared to those fed soy proteins, in all sampled tissues except in the intestine, and the amplitude of Δ15N differences between diets differed between tissues. Both between-tissue and between-diet Δ15N differences are probably related to modulations of the relative orientation of dietary and endogenous amino acids in the different metabolic pathways. More specifically, the smaller Δ15N values observed in tissue proteins with milk than soy dietary protein may be due to a slightly more direct channeling of dietary amino acids for tissue protein renewal and to a lower recycling of amino acids through fractionating pathways. In conclusion, the present data indicate that natural Δ15N of tissue are sensitive markers of the specific subtle regional modifications of the protein and amino acid metabolism induced by the protein dietary source

Endotoxin concentration in poultry houses for laying hens kept in cages or in alternative housing systems

International audience1. Endotoxins as components of organic dust may have adverse effects on the respiratory health of workers in poultry buildings. The move towards more welfare-friendly housing systems for layers may increase worker exposure to air contaminants due to the use of litter. 2. The endotoxin concentrations in the inhalable fraction of airborne dust (below 100 µm) from cage and alternative system henhouses (on-floor, free range and aviaries) were compared under both experimental and commercial conditions. 3. The endotoxin concentration was higher in experimental aviaries (median: 565 EU/m3, range: 362-1,491 EU/m3) than in cage housing (98 EU/m3 (51-470)). 4. In field conditions, the endotoxin concentration in the air of 13 alternative henhouses was higher (35 to 3,156 EU/m3) than in cage system buildings (n=8, 78-576 EU/m3). It was correlated to the respirable dust concentration (fraction below 5 µm) and to the temperature inside the henhouse but no seasonal variation was observed. 5. The present study emphasizes that considerable worker exposure to endotoxins may occur in henhouses especially in alternative systems

Preabsorptive factors are not the main determinants of intake depression induced by a high-protein diet in the rat

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