Effects of interactions between feeding practices, animal health and farm infrastructure on technical, economic and environmental performances of a pig-fattening unit.

European pig production faces economic and environmental challenges. Modelling can help farmers simulate and understand how changes in their management practices affect the efficiency of their production system. We developed an individual-based model of a pig-fattening unit that considers individual variability in performance among pigs, farmers' feeding practices and animal management and estimates environmental impacts (using life cycle assessment) and economic results of the unit. We previously demonstrated that this model provides reliable estimates of farm performance for different combinations of management practices, pig types and building characteristics. The objectives of this study were to quantify how interactions between feeding practices and animal management influence fattening unit results in healthy or impaired health conditions using the model. A virtual experiment was designed to evaluate effects of interactions between feeding practices, health status of the pig herd and infrastructure constraints on the technical performance, economic results and environmental impacts of the unit. The virtual experiment consisted of 96 scenarios, which combined chosen values of 6 input parameters of the model: batch interval (35 days and 7 days), use or non-use of a buffer room to manage the lightest pigs, feed rationing (ad libitum and restricted) and sequence plans (two-phase (2P), daily-phase (DP)), scale at which the feeding plan is applied (i.e. room, pen and individual) and health status of the pig herd (i.e. healthy v. impaired). Variance analysis was used to test effects of the factors in these 96 scenarios, and multivariate data analyses were used to classify the scenarios. Healthy populations obtained on average higher economic results (e.g. gross margin of 11.20 v. 1.50 €/pig) and lower environmental impacts (e.g. 2.24 v. 2.38 kg CO2-eq/kg pig live weight gain) than the population with impaired health. With 35 days batch interval and DP feeding, populations with impaired health reached gross margin similar to healthy populations with 2P ad libitum feeding and 7 days batch interval. Restricted, DP and individual feeding plans improved the economic and environmental performances of the unit for both health statuses. This study highlighted that health status of the pig herd is the main factor that affects technical, economic and environmental performances of a pig-fattening unit, and that adequate feeding strategies and animal management can compensate, to some extent, the effects of impaired health on environmental impacts but not on gross margin.

Modelling interactions between farmer practices and fattening pig performances with an individual-based model.

European pig production continues to encounter economic and environmental challenges. To address these issues, methods have been developed to assess performances of pig production systems. Recent studies indicate that considering variability in performances among pigs improves the accuracy and reliability of results compared with modelling an average animal. Our objective was to develop a pig fattening unit model able to (i) simulate individual pig performances, including their variability in interaction with farmers' practices and management, and (ii) assess their effects on technical, economic and environmental performances. Farmer practices included in the model were chosen from a typology generated from on-farm surveys focused on batch management, pig allocation to pens, pig feeding practices, practices of shipping to the slaughterhouse, and management of the remaining pigs. Pigs are represented using an individual-based model adapted from the InraPorc® model. To illustrate the model's abilities, four scenarios were simulated that combine two feed rationing plans (ad libitum, restricted to 2.5 kg/day) and two feed sequence plans (two-phase, 10-phase). Analysis of variance was performed on the simulated technical, economic and environmental indicators (calculated via Life Cycle Assessment). The feed rationing plan and feed sequence plan significantly affected all indicators except for the premium per pig, for which the feed sequence plan did not have a significant effect. The 'restricted 10-phase' scenario maximised gross margin of the fattening unit (14.2 €/pig) and minimised environmental impacts per kg of pig produced. In contrast, the 'ad libitum two-phase' scenario generated the lowest margin (8.20 €/pig) and the highest environmental impacts. The model appears to be a promising tool to assess effects of farmers' practices, pig characteristics and farm infrastructure on technical, economic and environmental performances of the fattening unit, and to investigate the potential of improvement. However, further work is needed, based on virtual experiments, in order to evaluate the effects of a larger diversity of practices.

White piedra and Trichosporon species in equatorial Africa. II. Clinical and mycological associations: an analysis of 449 superficial inguinal specimens.

Eighty-one of 449 Gabonese female patients examined were found to be positive for genitopubic white piedra. The association with trichobacteriosis is frequent (53 cases), and mostly seen with inguinal intertrigo. Fifty-two strains belonging to the genus Trichosporon were isolated from genital hairs as well as from inguinal intertrigo lesions. These strains were identified in accordance with previously defined morphological and biochemical criteria. Three species were recognized: T. mucoides (25 strains), T. inkin (20 strains) and T. asahii (seven strains). Their macroscopic and microscopic morphological properties, as well as their ability to reduce tetrazolium, were determined. In addition, the study of the clinical and pathogenic associations in which each of these strains was involved revealed some of their particular properties.

[Multifocal fibrosclerosis (retroperitoneal, mediastinal, mesenteric and pelvic involvement) associated with vasculitis and revealed by a livedo: clinical, histopathological and ultrastructural study in a case (author's transl)]. / Fibrosclérose multifocale (médiastinale, rétropéritonéale, pelvienne, avec mésentérite rétractile) associée a une vascularite et révélée par un livedo. Etude clinique, histopathologique et ultrastructurale.

A 22-year-old male patient was seen with vasculitis and subcutaneous nodules on arms and legs. Discret thoracic venous dilations were noticed and venography demonstrated obstruction of the superior vena cava. Clinical and biological examination, roentgenograms revealed no sign of immunological disease but led to the diagnosis of mediastinal and retroperitoneal idiopathic fibrosis. No drug could be incriminated. Right hydronephrosis obliged to a surgical bilateral ureterolysis combined with systemic steroid therapy. Histological and ultrastructural examinations on retroperitoneal biopsies showed dense collagenous fibrosis, with vasculitis. Perivascular infiltrate was mainly composed of extravased erythrocytes and lymphocytes. Fibrin deposits were seen around implicated vessels. Direct immunofluorescence investigations were negative. These morphological features seem to be in agreement with the physiopathological hypothesis of sclerosis. No retroperitoneal or mediastinal fibrosis extension occurred three years after surgical procedure, and under corticosteroid therapy. Similar vasculitis with mediastinal and retroperitoneal idiopathic fibrosis have previously been reported in only one case by R. W. Carton and R. Wrong. Multifocal fibrosclerosis is the generic term currently used, since Comings et al. (1967), to describe a group of fibrosing conditions which affect separate organ systems. Findings suggest that retroperitoneal fibrois, mediastinal fibrosis, sclerosing cholangitis, Riedel's thyroiditis and pseudotumors of the orbit may be different manifestations of a single disease whose pathogenesis remains obscure.