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A field study was carried out to evaluate the effect of vaccination against swine enzootic pneumonia in different production systems (closed or one-site, and open, two- or three-site, systems). The percentage of mortality showed statistically significant differences (p < 0.001) in favour of vaccination in all the production systems examined. Zootechnical and economic parameters also reflected the benefits of vaccination, although only the feed conversion ratio showed statistically significant differences (p < 0.030). A macroscopic study of lungs at slaughter pointed to statistically significant differences (p < 0.001) in favour of vaccination in the one- and two-site production systems. The histopathological and immunocytochemical study showed complete concordance with the macroscopic diagnosis (p < 0.001). Such relationship confirms the suitability of macroscopic diagnosis in field conditions. 相似文献
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The pathogenicity of three isolates of porcine respiratory coronavirus (AR310, LEPP and 1894) from the USA was assessed in specific pathogen-free pigs. Pigs inoculated with 1894 developed mild respiratory disease and pigs inoculated with AR310 and LEPP developed moderate respiratory disease from four to 10 days after they were inoculated, but all the pigs recovered fully by 14 days after inoculation. Gross and microscopic examination revealed mild (1894) to moderate (AR310 and LEPP) multifocal bronchointerstitial pneumonia from four to 10 days after inoculation. The lesions were characterised by necrotising bronchiolitis, septal infiltration with mononuclear cells, and a mixed alveolar exudate. No clinical signs or microscopic lesions were observed in control pigs that had not been inoculated. 相似文献
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Evaluation of the zootechnical parameters of vaccinating against swine enzootic pneumonia under field conditions 总被引：2，自引：0，他引：2
A field test was carried out in different production systems to evaluate the effect of vaccination against swine enzootic pneumonia with an inactivated vaccine. A total of 13,691 pigs of four different genetic origins were used, of which 7,351 were vaccinated and 6,340 were used as controls. The animals were housed in 16 fattening units, in which the 'one-site', 'two-site' and 'three-site' production systems were represented. There were the following statistically significant differences in favour of the vaccinated animals: a 1.89 per cent lower mortality (P<0.001), a 0.09 lower feed conversion ratio (P<0.030), a 3.12 per cent lower cost per kilogram gained in fattening (P<0.031), a 4.02 per cent lower cost per kilogram of carcase (P<0.018), a 3.77 per cent lower cost of feed per kilogram gained in fattening (P<0.012) and a 56.75 per cent lower potential loss of profit per kilogram gained in fattening due to mortality (P<0.001). An analysis of variance of the effects of genetic origin, treatment and production system on the different parameters showed that only the treatment had any statistically significant effect on the percentage mortality (P<0.002), feed conversion ratio (P<0.030), cost per kilogram gained in fattening (P<0.019), cost per kilogram of carcase (P<0.020), cost of feed per kilogram gained in fattening (P<0.015) and potential loss of profit per kilogram gained in fattening due to mortality (P<0.002). 相似文献
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Francisco J. Martín‐Peinado Francisco Bruno Navarro Maria Noelia Jimnez Manuel Sierra Francisco J. Martínez Ana Romero‐Freire Leopoldo Rojo Emilia Fernndez‐Ondoo 《Land Degradation \u0026amp; Development》2016,27(7):1709-1720
This work evaluated how pine plantations established on old fields and degraded lands influence soil properties in comparison with adjacent unplanted areas that undergo into secondary succession, and native forests, analysing the effects of abiotic variables and stand characteristics in the afforestation process. Thirty‐two paired sites (pine plantations versus unplanted areas) and 10 native forests were selected in the SE Spain. In total, 74 soil profiles were studied, and 222 composite soil samples were collected at three different depths. Soil organic carbon, cation exchange capacity, and C : N ratio showed significantly greater values in pine plantations in relation to the unplanted areas (0–5 cm), and the mean values of soil organic carbon, nitrogen (N), C : N ratio, and cation exchange capacity in these pine plantations were similar to those found under native forests. Only K+ concentrations were clearly higher in the native forests than in the other land uses for all depths analysed. Pine plantations in the drier and warmer areas showed lower soil quality in relation to the paired unplanted areas, as well as the younger and denser ones; it may be because under these situations, more time is needed to produce an improvement. In fact, the paired net variations increased with the stand age and/or tree size. In conclusion, pine plantations were in general more efficient in improving parameters related to soil quality, especially in locations with high soil water retention capacity, which in our study area were found at higher and cooler elevations. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Noelia González LópezAndrés Moure Herminia DomínguezJuan C. Parajó 《Industrial Crops and Products》2012,36(1):172-176
Chestnut is a valuable fruit with traditional food applications due to its nutritional value. The shell accounts for around 10% of the fruit weight and have no commercial applications, so they are destined for fuel. The development of alternative applications for the shells could contribute to valorization of the major constituents and to an integral utilization of renewable resources of low cost and residual origin according to a sustainable development philosophy.Husks come from two different peeling treatments, a dry dehusking process and a wet dehusking process. Husks from the dry process contained more lipophilic compounds as those hulls coming from the wet dehusking process.Treatments of chestnut husks were performed to release tannins and hemicelluloses components. High temperature extraction (HTE) was the selected technology, and aqueous and alkaline media were the solvents chosen. Treatments allowed the solubilisation of 37.7% of the chestnut husks, with maximum values of 55.5% of phenolic compounds solubilisation at treatment temperature of 180 °C. The higher antioxidant activity had a maximum value of 1.87 g Trolox/gram of extract at 160 °C.The extract produced under the optimal processing alkaline conditions was processed by membrane technology and the phenolic concentration in the final product was about 15% higher than the initial phenolic concentration in the hydrolyzates. This product showed an antioxidant activity comparable to that of synthetic antioxidants. 相似文献
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Porcine circovirus type 2 (PCV-2) coinfections in US field cases of postweaning multisystemic wasting syndrome (PMWS). 总被引：18，自引：0，他引：18
F J Pallarés P G Halbur T Opriessnig S D Sorden D Villar B H Janke M J Yaeger D J Larson K J Schwartz K J Yoon L J Hoffman 《Journal of veterinary diagnostic investigation》2002,14(6):515-519
The prevalence of different pathogens detected in combination with porcine circovirus type 2 (PCV-2) was studied retrospectively in field cases of postweaning multisystemic wasting syndrome (PMWS) diagnosed at the Iowa State University Veterinary Diagnostic Laboratory, Ames, Iowa, between January 2000, and September 2001. The presence of PCV-2 antigen in lymphoid tissues and/or lung, demonstrated by immunohistochemistry, together with moderate to severe lymphoid depletion and/or granulomatous lymphadenitis, was used as the criteria for the diagnosis of PMWS. A total of 484 cases fulfilled these criteria. Most of the cases (294/369) of PMWS occurred in pigs between the ages of 8 and 18 weeks, with a peak at 10 weeks of age. Porcine reproductive and respiratory syndrome virus was detected in 51.9% of the cases, Mycoplasma hyopneumoniae in 35.5%, bacterial septicemia in 14.0%, bacterial pneumonia in 7.6%, swine influenza virus in 5.4%, and PCV-2 alone in 1.9%. In cases with bacterial septicemia the most frequently isolated pathogen was Streptococcus suis. In cases with bacterial pneumonia, Pasteurella multocida was the most prevalent. 相似文献