Managing the transition from purebred to rotational crossbred dairy cattle herds: three technical pathways from a retrospective case-study analysis.

The growing interest in rotational crossbreeding in Western countries is due to its potential to improve reproductive and health performances of cows. Although a large amount of research focuses on assessing crossbred cows' performances, how to manage the transition from purebred to rotational crossbred herds is under-explored. Based on a retrospective analysis of French dairy herd case studies, we aimed to identify and characterise technical pathways to make such a transition. In 2018, we performed semi-directive interviews on 26 commercial dairy farms. Data were collected to describe changes in breeding, replacement and culling management practices from the first crossbred mating with purebred cows to the management of a mainly crossbred herd in 2018. Based on a multivariate analysis, we identified two main guidelines structuring technical pathways to move towards rotational crossbred herds: (i) the depth and scale of change (i.e. farm v. herd) associated with the introduction of rotational crossbreeding in the whole-farm dynamics and (ii) the changes in herd replacement and breeding practices to adapt to the evolution of herd demographics induced by the evolution of the dairy crossbred mating rate over time (high from the beginning v. distributed over time). Hierarchical clustering discriminated three groups of farmers differing in their technical pathway to move towards a rotational crossbred herd. In pathway 1, farmers customised one or several rotational crossbreeding schemes to support whole-farm transition towards an organic or grass-based system. Once the scheme stabilised, they quickly implemented it and had to readjust replacement and culling practices to regulate imbalance in herd demographics induced by the improvement in cow fertility. In pathway 2, farmers also customised one or several rotational crossbreeding schemes to support whole-farm redesign but they implemented it more gradually in the herd, which induced no major imbalance in herd demographics. In pathway 3, farmers predefined a relatively well-known rotational crossbreeding scheme to correct fertility issues of purebred cows without any changes at the farm level. They implemented it quickly from the beginning and had to adapt herd replacement and culling to regulate imbalance in herd demographics induced by the improvement in cow fertility. These first empirical evidences on how dairy farmers manage the transition from a purebred to rotational crossbred herd provide original scientific and operational contributions.

A glimpse of gluons through deeply virtual compton scattering on the proton.

The internal structure of nucleons (protons and neutrons) remains one of the greatest outstanding problems in modern nuclear physics. By scattering high-energy electrons off a proton we are able to resolve its fundamental constituents and probe their momenta and positions. Here we investigate the dynamics of quarks and gluons inside nucleons using deeply virtual Compton scattering (DVCS)-a highly virtual photon scatters off the proton, which subsequently radiates a photon. DVCS interferes with the Bethe-Heitler (BH) process, where the photon is emitted by the electron rather than the proton. We report herein the full determination of the BH-DVCS interference by exploiting the distinct energy dependences of the DVCS and BH amplitudes. In the regime where the scattering is expected to occur off a single quark, measurements show an intriguing sensitivity to gluons, the carriers of the strong interaction.

Initial insights on the performances and management of dairy cattle herds combining two breeds with contrasting features.

Finding ways of increasing animal production with low external inputs and without compromising reproductive performances is a key issue of livestock systems sustainability. One way is to take advantage of the diversity and interactions among components within livestock systems. Among studies that investigate the influence of differences in animals' individual abilities in a herd, few focus on combinations of cow breeds with contrasting features in dairy cattle herds. This study aimed to analyse the performances and management of such multi-breed dairy cattle herds. These herds were composed of two types of dairy breeds: 'specialist' (Holstein) and 'generalist' (e.g. Montbeliarde, Simmental, etc.). Based on recorded milk data in southern French region, we performed ANOVA: (i) to compare the performances of dairy herds according to breed-type composition: multi-breed, single specialist breed or single generalist breed and (ii) to test the difference of milk performances of specialist and generalist breed cows (n = 10 682) per multi-breed dairy herd within a sample of 22 farms. The sampled farmers were also interviewed to characterise herd management through multivariate analysis. Multi-breed dairy herds had a better trade-off among milk yield, milk fat and protein contents, herd reproduction and concentrate-conversion efficiency than single-breed herds. Conversely, they did not offer advantages in terms of milk prices and udder health. Compared to specialist dairy herds, they produce less milk with the same concentrate-conversion efficiency but have better reproductive performances. Compared to generalist dairy herds, they produce more milk with better concentrate-conversion efficiency but have worse reproductive performances. Within herds, specialist and generalist breed cows significantly differed in milk performances, showing their complementarity. The former produced more milk for a longer lactation length while the latter produced milk with higher protein and fat contents and had a slightly longer lactation rank. Our results also focus on the farmers' management of multi-breed dairy herds underlying herd performances. Three strategies of management were identified and structured along two main axes. The first differentiates farmers according to their animal-selection practices in relation with their objectives of production: adapting animal to produce milk with low-feeding inputs v. focussing on milk yield trait to intensify milk production. The second refers to the purpose farmers give to multi-breed dairy herds: milk v. milk/meat production. These initial insights on the performances and management of multi-breed dairy herds contribute to better understanding the functioning of ruminant livestock systems based on individual variability.

Bridgehead invasion of a monomorphic plant pathogenic bacterium: Xanthomonas citri pv. citri, an emerging citrus pathogen in Mali and Burkina Faso.

Molecular epidemiology studies further our understanding of migrations of phytopathogenic bacteria, the major determining factor in their emergence. Asiatic citrus canker, caused by Xanthomonas citri pv. citri, was recently reported in Mali and Burkina Faso, a region remote from other contaminated areas. To identify the origin and pathways of these emergences, we used two sets of markers, minisatellites and microsatellites, for investigating different evolutionary scales. Minisatellite typing suggested the introduction of two groups of strains in Mali (DAPC 1 and DAPC 2), consistent with microsatellite typing. DAPC 2 was restricted to Bamako district, whereas DAPC 1 strains were found much more invasive. The latter strains formed a major clonal complex based on microsatellite data with the primary and secondary founders detected in commercial citrus nurseries and orchards. This suggests that human activities played a major role in the spread of DAPC 1 strains via the movement of contaminated propagative material, further supported by the frequent lack of differentiation between populations from geographically distant nurseries and orchards. Approximate Bayesian Computation analyses supported the hypothesis that strains from Burkina Faso resulted from a bridgehead invasion from Mali. Multi-locus variable number of tandem repeat analysis and Approximate Bayesian Computation are useful for understanding invasion routes and pathways of monomorphic bacterial pathogens.

New multilocus variable-number tandem-repeat analysis tool for surveillance and local epidemiology of bacterial leaf blight and bacterial leaf streak of rice caused by Xanthomonas oryzae.

Multilocus variable-number tandem-repeat analysis (MLVA) is efficient for routine typing and for investigating the genetic structures of natural microbial populations. Two distinct pathovars of Xanthomonas oryzae can cause significant crop losses in tropical and temperate rice-growing countries. Bacterial leaf streak is caused by X. oryzae pv. oryzicola, and bacterial leaf blight is caused by X. oryzae pv. oryzae. For the latter, two genetic lineages have been described in the literature. We developed a universal MLVA typing tool both for the identification of the three X. oryzae genetic lineages and for epidemiological analyses. Sixteen candidate variable-number tandem-repeat (VNTR) loci were selected according to their presence and polymorphism in 10 draft or complete genome sequences of the three X. oryzae lineages and by VNTR sequencing of a subset of loci of interest in 20 strains per lineage. The MLVA-16 scheme was then applied to 338 strains of X. oryzae representing different pathovars and geographical locations. Linkage disequilibrium between MLVA loci was calculated by index association on different scales, and the 16 loci showed linear Mantel correlation with MLSA data on 56 X. oryzae strains, suggesting that they provide a good phylogenetic signal. Furthermore, analyses of sets of strains for different lineages indicated the possibility of using the scheme for deeper epidemiological investigation on small spatial scales.

[Leptospirosis in Libreville (Gabon): four cases]. / La leptospirose à Libreville (Gabon) : à propos de quatre cas.

OBJECTIVE: Leptospirosis is an endemic disease in tropical countries, where it is characterized by clinical polymorphism. We report four cases of leptospirosis diagnosed at the military hospital of Libreville (Gabon). CASE REPORTS: Four men aged 16 to 31-years-old, were admitted for febrile jaundice, with impaired general condition and pain. All lived in disadvantaged neighborhoods in the capital. In each case, the laboratory workups found hepatic cytolysis, renal failure, hyperleukocytosis, anemia, and an inflammatory state. Serology was negative for hepatitis B and C and for HIV, as was testing for malaria. The failure to respond to presumptive antimalarial treatment suggested leptospirosis, and the diagnosis was confirmed in every case by positive serologies with significant antibody titers. The course was quickly favorable under treatment by an appropriate antibiotic; liver and kidney function returned to normal within a few days. CONCLUSION: In tropical zones, the diagnosis of leptospirosis must be considered in all cases of febrile jaundice, especially when liver and kidney function are impaired.

Understanding beef-cattle farming management strategies by identifying motivations behind farmers' priorities.

This study aimed to identify and better understand management strategies that help livestock farmers adapt to changes in their production contexts, a fundamental challenge. A total of nine beef-cattle farmers were interviewed three times over 1 year to discuss 13 dimensions of livestock farming (e.g. reproduction, feeding, sales, etc.). Characterisation of management strategies rested on three main factors: (i) ranking of the dimensions according to the degree to which farmers desired to control them, (ii) reasons for the ranking and (iii) management guidelines. Although farmers agreed upon the rank of certain dimensions, such as herd management, they differed on that of others, such as sales and administration/regulations. Four motivation categories were identified: risk, pleasure, efficiency and ability to control the dimension. Three management guidelines were identified, which indicated that farmers managed for future survival of their farms at different scales (animal/herd v. whole-farm), involving different resources (biological v. financial) and based on different animal categories (reproductive cows v. animals sold). These results improve understanding of individual livestock farmers and their current management strategies by integrating the motivations behind their strategies. For this reason, they constitute methodological elements that agricultural advisors can use to provide relevant information to farmers while accommodating differences in farm management.

A conceptual model of farmers' informational activity: a tool for improved support of livestock farming management.

Farmers have been slow to adopt decision support system (DSS) models and their outputs, mainly owing to (i) the complexity of the data involved, which most potential users are unable to collect and process; and (ii) inability to integrate these models into real representations of their informational environments. This situation raises questions about the way farm management researchers have modelled information and information management, and especially about the quality of the information assessed by the farmers. We consider that to review advisory procedures we need to understand how farmers select and use farm management-related information, rather than focusing on decisions made in particular situations. The aim of this study was to build a conceptual model of the farmer-targeted farm management-related information system. This model was developed using data collected in commercial beef cattle farms. The design structure and operational procedures are based on (i) data categories representing the diversity of the informational activity; and (ii) selected criteria for supporting decisions. The model is composed of two subsystems, each composed of two units. First, an organizational subsystem organizes, finalizes and monitors informational activity. Second, a processing subsystem builds and exploits the informational resources. This conceptual model makes it possible to describe and understand the diverse range of farmers' informational activity by taking into account both the flow of information and the way farmers make sense of that information. This model could serve as a component of biodecisional DSS models for assigning information in the decision-making process. The next task will be to take into account the broad range of farmers' perceptions of the management situations in DSS models.

Phase I and pharmacokinetic (PK) study of MAG-CPT (PNU 166148): a polymeric derivative of camptothecin (CPT).

Polymeric cytotoxic conjugates are being developed with the aim of preferential delivery of the anticancer agent to tumour. MAG-CPT comprises the topoisomerase I inhibitor camptothecin linked to a water-soluble polymeric backbone methacryloylglycynamide (average molecular weight 18 kDa, 10% CPT by weight). It was administered as a 30-min infusion once every 4 weeks to patients with advanced solid malignancies. The objectives of our study were to determine the maximum tolerated dose, dose-limiting toxicities, and the plasma and urine pharmacokinetics of MAG-CPT, and to document responses to this treatment. The starting dose was 30 mg m(-2) (dose expressed as mg equivalent camptothecin). In total, 23 patients received 47 courses at six dose levels, with a maximum dose of 240 mg m(-2). Dose-limiting toxicities were myelosuppression, neutropaenic sepsis, and diarrhoea. One patient died after cycle 1 MAG-CPT at the maximum dose. The maximum tolerated dose and dose recommended for further clinical study was 200 mg m(-2). The half-lives of both MAG-CPT and released CPT were prolonged (>6 days) and measurable levels of MAG-CPT were retrieved from plasma and urine 4 weeks after treatment. However, subsequent pharmacodynamic studies of this agent have led to its withdrawal from clinical development.

A matched comparison of the combination of prehospital thrombolysis and standby rescue angioplasty with primary angioplasty.

This study sought to assess the rate of acute Thrombolysis In Myocardial Infarction (TIMI) trial grade 3 patency that can be achieved with the combination of prehospital thrombolysis and standby rescue angioplasty in acute myocardial infarction. No large angiographic study has been performed after prehospital thrombolysis to determine the 90-minute TIMI 3 patency rate in the infarct-related artery. Hospital outcome and artery patency were compared to 170 matched patients treated with primary angioplasty. Prehospital thrombolysis was applied 151+/-61 minutes after the onset of pain in 170 patients (56+/-12 years, 86% men), using recombinant tissue-type plasminogen activator, streptokinase, or eminase. Emergency 90-minute angiography was performed in every case. All patients in whom thrombolysis failed underwent rescue angioplasty. After thrombolysis alone, TIMI grade 3 flow in the infarct-related artery was observed in 108 patients (64%), TIMI grade 2 in 12 (7%), and TIMI grade 0 or 1 in 50 (29%). Rescue angioplasty was successful in 47 of 50 attempts. Overall, TIMI 3 patency was achieved in 91%, and additionally TIMI 2 flow in 7% of patients, an average of 113+/-39 minutes after thrombolysis and 55+19 minutes after admission. Therefore, < 2 hours after thrombolysis, only 2% of patients had persistent occlusion (TIMI 0 or 1) of the infarct-related artery. In-hospital mortality was 4% overall (7 of 170), and 3% in the 155 patients in whom TIMI 3 was obtained during the acute phase. Severe hemorrhagic complications occurred in 14 patients (8%) with 2 fatal cerebral hemorrhages (7% of patients required transfusions). The matched comparison with primary PTCA showed no significant difference in hospital outcome. Combined prehospital thrombolysis, 90-minute angiography, and rescue angioplasty yield a high rate of acute TIMI 3 patency rate early after thrombolysis and hospital admission. A randomized, prospective comparison between these 2 reperfusion strategies may be now warranted.

The esthetic width in fixed prosthodontics.

With the evolution of adhesive dentistry and the increasing use of porcelain veneers, single-unit crowns generally are restricted to the replacement of pre-existing full-coverage crowns and the restoration of nonvital and/or severely damaged teeth. Porcelain-fused-to-metal restorations are still widely used to generate single-unit crowns and fixed partial dentures. Collarless metal-ceramic restorations represent the most successful evolution among efforts to meet maximum esthetic requirements using porcelain-fused-to-metal restorations. Extended metal frameworks and opaque aluminous ceramic cores are associated with unpleasant optical effects in the soft tissues surrounding such restorations. This problem is particularly evident in the presence of the upper lip, which can generate an "umbrella effect" characterized by gray marginal gingivae and dark interdental papillae. Based on the concept of the biologic width, a systematic approach is proposed for the elaboration of an "esthetic width," including: 1) positioning of preparation margins; 2) reduction of the metal framework; and (c) appropriate marginal design of porcelain-fused-to-metal restorations. Strategic features of pontics and a specific interdental design are suggested to compensate for deficient anatomical features of the soft tissue and the edentulous ridge.

Photodynamic therapy of facial squamous cell carcinoma in cats using a new photosensitizer.

BACKGROUND AND OBJECTIVE: Photodynamic therapy has been shown to be an effective treatment modality for surface-oriented neoplasms of the skin, respiratory, gastrointestinal, and urogenital systems. The purpose of this study was to assess the safety and efficacy of photodynamic therapy using a new photosensitizer in the treatment of squamous cell carcinomas of the feline facial skin. STUDY DESIGN/MATERIALS AND METHODS: Cats with naturally occurring squamous cell carcinomas of the facial skin were entered into the study. Tumors were staged using a modification of the World Health Organization (WHO) system for classification of feline tumors of epidermal origin. Photodynamic therapy was delivered to the tumors using an argon-pumped dye laser 24 hours after the administration of the photosensitizer pyropheophorbide-alpha-hexyl-ether (HPPH-23). Following treatment, tumors were evaluated for complete response rates and local control durations. RESULTS: Fifteen tumors were staged T1a (< 1.5 cm diameter, noninvasive), 18 T1b (< 1.5 cm, invasive), and 28 T2B (> 1.5 cm, invasive). Complete response rates as well as local control durations were significantly (P < 0.05) related to stage. Complete response was achieved in 100% of T1a tumors, 56% of T1b tumors, and 18% of T2b tumors. One-year local control rates were 100% for T1a tumors and 53% for T1b tumors; overall 1-year local control rate for all treated tumors was 62%. Clinical, hematological, and biochemical evidence of toxicity was not seen in any cat following drug administration. However, morbidity was observed following treatment of large, invasive tumors of the nasal plane. CONCLUSION: Photodynamic therapy with the photosensitizer HPPH-23 was safe and effective in treating early stage squamous cell carcinomas of the feline nasal plane and facial skin. However, toxicity was encountered following treatment of large neoplasms.

[Evaluation of acute pain in prehospital medicine]. / Evaluation de la douleur aiguë en médecine préhospitalière.

OBJECTIVE: To evaluate acute pain in prehospital setting. STUDY DESIGN: Prospective survey. PATIENTS: All eligible patients during a 3-month-period, excepted children less than 10-year-old. METHOD: Pain intensity was evaluated by verbal rating scale with 5 points (VRS), visual analog scale (VAS), demand for antalgics by the patient and the relief obtained. These data were collected at the beginning (T0) and the end (Tend) of medical management. Analgesic treatments were let at the physician's choice. RESULTS: A series of 255 patients were included (mean age 58 +/- 1.5 SEM, sex-ratio 57M/43F). Among them, 42% experienced pain at VRS. VAS could be used in 60% of patients. VRS evaluated by the patient was correlated to the VAS (P < 0.001). Among those with significant pain (defined by a VAS > or = 30 mm), only 31% asked for analgesia and 64% received analgesics. Pain scales (VRS and VAS) were significantly improved (P < 0.001) at the end of the medical management, except for patients who did not receive any treatment. However, mean VAS was still above 30 mm, even in patients receiving analgesics. Only 49% of patients expressed a good relief at the end of the medical management. CONCLUSION: Acute pain is frequently observed in prehospital emergency medicine. Pain scales such as VRS and VAS are used easily and convenient for the assessment of pain intensity in this context. However, even if pain is correctly evaluated, it is still inadequately treated. The reasons of these inadequacies must be assessed and corrected with pain treatment protocols including opioids.

The diagnostic template: a key element to the comprehensive esthetic treatment concept.

Provisional restorations represent a key element in the realization of extensive esthetic rehabilitations. In particular, they provide indispensible diagnostic information contribute significantly to adjacent soft tissue conditioning, and ensure the patient's comfort during the intermediate phase of treatment. The-treatment outcome strongly depends on the treatment approach chosen. This article describes a treatment rationale comprising the use of a diagnostic template. This type of work strategy, documented with clinical cases, integrates diagnostic waxups and indirect provisional restorations using simplified and efficient fabrication techniques.

Photodynamic therapy in veterinary medicine: current status and implications for applications in human disease.

The historical development and published veterinary applications of photodynamic therapy are reviewed. Potential animal models, using naturally-occurring diseases in veterinary patients, for the future development of photodynamic therapy are described.

[Decubitus ulcers ... again and always]. / Les escarres... encore et toujours!

This article is the result of a comparative study during 1994 and 95 concerning escar prevalence in our Nephrology intensive care unit. Combined paramedical and medical activities concerning preventive and curative care, structured assessment (...), made it possible to decrease escar' prevalence from 19% (1994) to 12% (1995).