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991.
992.
东营市干旱灾害风险区划方法初探 总被引:1,自引:0,他引:1
本文对近30年东营市干旱气候特征和灾害发生情况进行统计分析,采用频率统计、层次分析、专家打分、加权综合评价方法和GIS技术,计算出全市各区域干旱灾害的风险系数。进而对东营市干旱灾害进行风险区划。 相似文献
993.
994.
Karin Persson Waller Ylva Persson Ann-Kristin Nyman Lena Steng?rde 《Acta veterinaria Scandinavica》2014,56(1):9
Background
Studies outside the Nordic countries have indicated that subclinical mastitis (measured by milk somatic cell count or the California Mastitis Test), intramammary infections (IMI), or blind quarters in beef cows may have negative effects on beef calf growth. Knowledge on prevalence of such udder health problems in Swedish beef cows is scarce. Therefore, the main aim of this study was to investigate subclinical mastitis, IMI and udder conformation in a number of beef cow herds. Production of β-lactamase in staphylococci was also investigated. Associations between certain cow factors and subclinical mastitis and IMI, and associations between cow and calf factors and 200 day calf weaning weight were also studied. The herds were visited once within a month after calving and once at weaning. Udder examination and quarter milk sampling, for somatic cell count and bacteriology, were performed in 8 to 12 cows per herd and occasion.Results
Approximately 50%, 40% and 10% of the cows had subclinical mastitis, IMI, and at least one blind quarter, respectively, but the prevalence varied markedly between herds. Intramammary infections (mainly due to staphylococci) were identified in 13-16% of the milk samples. Less than 5% of the staphylococcal isolates produced β-lactamase. Approximately 11% of the cows sampled twice had the same IMI (mostly Staphylococcus aureus) at both samplings. Cow factors of importance for subclinical mastitis and/or IMI were teat and udder shape, breed, parity, presence of blind quarters, and cow hygiene. No significant associations were found between udder health parameters studied and calf weaning weights.Conclusions
Subclinical mastitis and IMI, but not blind quarters, were common in beef cows, but the prevalence varied markedly between herds. Most IMI were caused by staphylococci and more than 95% of those were sensitive to penicillin. Cows with large funnel-shaped teats or pendulous udder after calving, and cows with blind quarters were at risk of having subclinical mastitis and/or IMI. Poor hygiene was also a risk factor for udder health problems. No significant associations were found between udder health and calf weaning weight. More studies on risk factors are warranted to improve advisory services on awareness and prevention of mastitis in beef cows. 相似文献995.
Guillaume Fournié Bryony Anne Jones Wendy Beauvais Juan Lubroth Felix Njeumi Angus Cameron Dirk Udo Pfeiffer 《Preventive veterinary medicine》2014
In 2011, ten years after the last reported outbreak, the eradication of rinderpest was declared. However, as rinderpest virus stocks still exist, there remains a risk of rinderpest re-introduction. 相似文献
996.
Alicia Torralbo Carmen Borge Alberto Allepuz Ignacio García-Bocanegra Samuel K. Sheppard Anselmo Perea Alfonso Carbonero 《Preventive veterinary medicine》2014
An extensive epidemiological study was performed to determine the prevalence and risk factors of Campylobacter infection in broiler farms in Andalusia (southern Spain). A total of 2221 cloacal swabs and 747 environmental swabs from 291 broiler flocks were screened between April 2010 and May 2012. The prevalence of Campylobacter in individual animals was 38.1%, and the flock prevalence was 62.9%. Flocks were predominantly infected by C. jejuni and C. coli but were also infected by untyped Campylobacter spp., and mixed-species infection could be found. Risk factors for Campylobacter infection were assessed from direct interview of the farmers. The number of positive samples by flock was modelled assuming a binomial distribution. Analysis indicated five factors associated with increased intra-flock prevalence: presence of dogs or cats on the farm, older age of the broiler flock, the application of thinning of flocks, the presence of windows with canvas blinds, and the presence of rodents in the poultry house. Two factors were associated with decreased intra-flock prevalence: the treatment of drinking water and having an entrance room for access into the poultry house. This is the first study performed on broilers farms from Spain reporting the risk factors of Campylobacter infection and is the largest study on the prevalence of Campylobacter infection. 相似文献
997.
Ana V. Pascual-Linaza Beatriz Martínez-López Dirk U. Pfeiffer José Carlos Moreno Cristina Sanz José Manuel Sánchez-Vizcaíno 《Preventive veterinary medicine》2014
Extremadura has been one of the regions in Spain most severely affected by Bluetongue (BT) epidemics. The first incursion of BTV, which was successfully eradicated one year later, occurred in 2004, involving the BTV-serotype 4. However, a second incursion occurred in September 2007, this time involving serotype 1. Since then, the implementation of intensive vaccination programs have significantly reduced BTV-1 occurrence, but the disease has not been completely eradicated yet. 相似文献
998.
A.M.B. Veldhuis S. Carp-van Dijken L. van Wuijckhuise G. Witteveen G. van Schaik 《Veterinary microbiology》2014,168(2-4):281-293
In November 2011, the new orthobunyavirus Schmallenberg virus (SBV) was identified in dairy cows that had induced fever, drop in milk production and diarrhoea in the Netherlands (Muskens et al., 2012. Tijdschrift voor Diergeneeskunde 137, 112–115) and a drop in milk production in cows in Northwestern Germany (Hoffmann et al., 2012. Emerging Infectious Diseases 18 (3), 469–472), in August/September 2011. This study aimed at quantifying risk factors for high within-herd prevalence of SBV and SBV-induced malformations in newborn calves in dairy herds in the Netherlands. Additionally, the within-herd impact of SBV infection on mortality rates and milk production was estimated.A case-control design was used, including 75 clinically affected case herds and 74 control herds. Control herds were selected based on absence of malformations in newborn calves and anomalies in reproductive performance. SBV-specific within-herd seroprevalences were estimated. Risk factors for high within-herd SBV seroprevalence (>50%) and the probability of malformed newborn calves in a herd were quantified. In addition, within-herd impact of SBV with regard to milk production and mortality was estimated.Animal-level seroprevalence was 84.4% (95% confidence interval (CI): 70.8–92.3) in case herds and 75.8% (95% CI: 67.5–82.5) in control herds. Control herds that were completely free from SBV were not present in the study. Herds that were grazed in 2011 had an increased odds (OR 9.9; 95% CI: 2.4–41.2)) of a high seroprevalence (>50%) compared to herds that were kept indoors. Also, when grazing was applied in 2011, the odds of malformations in newborn calves tended to be 2.6 times higher compared to herds in which cattle were kept indoors. Incidence of malformations in newborn calves at herd level was associated with both within-herd seroprevalence and clinical expression of the disease in adult cattle.The rate of vertical transmission of SBV to the fetus once a dam gets infected seemed low. A total of 146 stillborn or malformed calves were submitted by 65 farmers during the study period, of which 19 were diagnosed as SBV-positive based on pathological investigation and/or RT-qPCR testing of brain tissue. Based on these results combined with calving data from these herds we roughly estimated that at least 0.5% of the calves born between February and September 2012 have been infected by SBV.A drop in milk production was observed between the end of August 2011 and the first half of September (week 35–36), indicating the acute phase of the epidemic. During a 4-week period in which SBV infection was expected to have occurred, the total loss in milk production in affected dairy herds was around 30–51 kg per cow. SBV had no or limited impact on mortality rates which was as expected given the relatively mild expression of SBV in adult cows and the low incidence of malformations in newborn calves. 相似文献
999.
Willard C. Losinger 《Aquaculture International》2006,14(5):415-419
Analysis of data from a cross-sectional survey of 571 catfish farmers in the four major catfish-producing states in the United States showed that variability in production fell as farm size increased. Increasing pond size was associated with increasing variability in production. The variance of production was higher on operations that had watershed ponds than on operations with levee ponds. 相似文献
1000.
Caroline Stanley Maura Hiney Deirdre Gilroy Richard Powell David Padley Pete Smith 《Aquaculture (Amsterdam, Netherlands)》2002,210(1-4):35-48
Two laboratory microcosms, constructed of sterilised sediment and water taken from different locations, were seeded with Aeromonas salmonicida. A non-quantitative PCR, a heterogeneous, non-competitive, sandwich ELISA and colony formation were employed to generate survival data. In one microcosm, all three analytical methods generated positive results over the full 279 days of the incubation of the system at 18 °C. In the second microcosm, constructed with humic acid-rich material, colony formation was undetectable after 1 day but the PCR and ELISA methods generated positive results for up to 269 days.
Direct injection into fish of material from the two microcosms both seeded with a passaged strain of A. salmonicida was used to determine the disease-producing potential of the bacteria in these systems. A direct correlation was observed between the presence of colony-forming units and the ability to produce furunculosis in test fish. None of the samples that generated positive PCR and ELISA signals but in which colony formation was not detected proved capable of inducing disease in fish. The significance of these data for the application of proxy methods in epizootiological studies is discussed. 相似文献