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Aznar I McGrath G Murphy D Corner LA Gormley E Frankena K More SJ Martin W O'Keeffe J De Jong MC 《Veterinary microbiology》2011,151(1-2):104-111
The principal wildlife reservoir of Mycobacterium bovis in Ireland is the European badger. Studies in the Republic of Ireland (RoI) have shown that badgers culled in association with cattle herd tuberculosis breakdowns (focal culling) have a higher prevalence of infection than the badger population at large. This observation is one rationale for the medium term national strategy of focal badger culling. A vaccination strategy for the control of bovine tuberculosis (bTB) in badgers is a preferred long-term option. The Bacillus Calmette-Guérin (BCG) vaccine has been shown to decrease disease severity in captive badgers under controlled conditions. As the vaccine has been tested in a controlled environment with precise information on infection pressure, it cannot be assumed a priori that the effects of vaccination are similar in the wild, where other environmental and/or ecological factors prevail. For this reason we have designed a vaccine field trial to assess the impact of vaccination on the incidence of TB infection in a wild badger population. The selected study area for the vaccine trial (approximately 755 square kilometers) is divided into three zones each of which has similar characteristics in terms of size, number of main badger setts, cattle herds, cattle and land classification type. Three vaccination levels (100%, 50% and 0%) will be allocated to the three zones in a way that a gradient of vaccination coverage North to South is achieved. The middle zone (zone B) will be vaccinated at a 50% coverage but zone A and C will be randomly allocated with 100% or 0% vaccination coverage. Vaccination within zone B will be done randomly at individual badger level. The objective of this paper is to describe the design of a field tuberculosis vaccination trial for badgers, the epidemiological methods that were used to design the trial and the subsequent data analysis. The analysis will enable us to quantify the magnitude of the observed vaccination effect on M. bovis transmission in badgers under field conditions and to improve our knowledge of the biological effects of vaccination on susceptibility and infectiousness. 相似文献
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Fiona M. Seaton Gaynor Barrett Annette Burden Simon Creer Eleonora Fitos Angus Garbutt Rob I. Griffiths Pete Henrys Davey L. Jones Patrick Keenan Aidan Keith Inma Lebron Lindsay Maskell M. Gloria Pereira Sabine Reinsch Simon M. Smart Bronwen Williams Bridget A. Emmett David A. Robinson 《European Journal of Soil Science》2021,72(6):2414-2429
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Soil structure is a dynamic property affected by physical, chemical, and microbiological processes. Addition of organic matter to soils and the use of different management practices have been reported to impact soil structure and crop production. Moderation in soil temperature and increases in microbial activity and soil water retention are often suggested as reasons for the rise in crop yield when organic matter is added to the soil. Less is known about the direct effect of changes in soil structure on crop production. A field experiment was conducted to study the effect of summer cover crop and in-season management system on soil structure. The experiment was a nested design with summer cover crop as the main plot and management system as the subplot. Summer cover crop treatments included cowpea (Vigna unguiculata L. Walp.) incorporated into the soil in the fall (CI), cowpea used as mulch in the fall (CM), sudangrass (Sorghum vulgare) incorporated into the soil in the fall (S), and dry fallow or bare ground (B). Management systems were organic (ORG) and conventional (CNV) systems. Lettuce (Lactuca sativa L.) and cantaloupes (Cucumis melo L.) were cultivated in rotation in the plots for three consecutive years using the same cover crops and management systems for each plot. Disturbed and undisturbed soil cores were collected at the end of the third year and used for laboratory experiments to measure physical, chemical, and hydraulic properties. Image analysis was used to quantify soil structure properties using a scanning electron microscope on thin sections prepared from the undisturbed soil cores. We found that total soil carbon was correlated with porosity, saturation percentage, and pore roughness. Pore roughness was correlated with crop production in general and with marketable production in particular. We found that the higher the complexity of the pore space, the more water retained in the soil, which may increase soil water residence and reduce plant water stress. 相似文献
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Effects of boron excess in nutrient solution on growth,mineral nutrition,and physiological parameters of Jatropha curcas seedlings 总被引：1，自引：0，他引：1
Inma Simón Leyanes Díaz‐López Vicente Gimeno Manuel Nieves Walter E. Pereira Vicente Martínez Vicente Lidon Francisco García‐Sánchez 《植物养料与土壤学杂志》2013,176(2):165-174
Jatropha curcas L. has recently attracted the attention of the international research community due to its potential as a biodiesel crop. In addition, its high resistance to drought and salinity is well known. Under arid and semiarid conditions, boron (B) concentrations in irrigation water can be higher than desired when water from industry, urban areas, or desalination is used. However, the growth and physiological responses of J. curcas plants to B excess in the irrigation water are unknown. Therefore, a greenhouse experiment was conducted to study the effects of B excess in the nutrient solution (0.25, 2, 4.5, and 7 mg L–1 B, applied as H3BO3) on plant growth, mineral concentration in the different plant tissues, photosynthesis, water relations, chlorophyll fluorescence, chlorophyll concentration (as SPAD values), and composition of carbohydrates. Plant growth decreased with increasing B concentration in the nutrient solution; growth reduction was higher for roots than for leaves or stems. The B concentration increased in all plant tissues, in the following order: leaf > root > stem. These data indicate that the roots of J. curcas are more sensitive to B toxicity than the leaves and that B has restricted mobility inside these plants, accumulating mainly in the basal and middle leaves via the transpiration stream. Increasing B concentration in leaves decreased the ACO2 and the stomatal conductance, but the leaf water parameters were not affected. The data for chlorophyll concentration and chlorophyll fluorescence indicated that nonstomatal factors were involved in the ACO2 decline, whereas decreases in the parameters of PSII photochemistry due to B toxicity suggest that there was structural damage in chloroplasts. There was also a general tendency for a decrease in nonstructural carbohydrates in all plant tissues, possibly due to the decline in ACO2. With excess B, the concentrations of K and Mg increased in leaves due to a decrease in the growth, while a typical antagonistic effect between B and P was evident from the P concentration decrease in leaves. In summary, J. curcas should be considered a B‐sensitive plant, as a leaf B concentration of 1.2 mg (g dw)–1 caused a growth decline of approximately 30%. 相似文献
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Jordi Roca Silvia Martínez Inma Parrilla Emilio A. Martínez 《Livestock Production Science》2005,94(3):169-177
Since rabbit bucks are usually housed under constant long daylight in artificial insemination (AI) centers, the main purpose of this study was to investigate whether constant long day influenced ejaculate parameters of rabbits housed in AI centers in the Spanish Mediterranean area. The study was carried out in Murcia, Spain (37° N). Twenty commercial hybrid male rabbits, aged between 14 and 15 weeks, were randomly allotted to two groups and housed under either natural day length (n=10, ND) or a constant 16-h daylight exposure of 16 h (n=10, CLD). Other management conditions, such as air temperature or reproductive handling, were identical for both groups. Two successive ejaculates were collected twice weekly from every male, and the first one was used to monitor ejaculate characteristics. Measurement of semen production, in terms of ejaculate and semen volume, sperm concentration and total sperm per ejaculate, and sperm quality, in terms of motility index, viability, morphology and acrosome integrity, was assessed in 783 ejaculates collected during 15 months (from October to December). No differences (P>0.05) in either semen production or sperm quality were shown among ejaculates collected from rabbits housed under ND and CLD conditions. A limited influence of season was observed (P<0.01); semen volume and motility index were highest and lowest, respectively, during summer. The increase of air temperature and humidity index (THI) had a significant detrimental effect (P<0.01) on both sperm production and quality parameters with a lag of 6 and 3 weeks, respectively. On the basis of these findings, annual variations of semen production and sperm quality in male rabbits seems more related to THI than to daylight length under conditions of AI management in the Mediterranean area of Spain. 相似文献
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