新疆生产建设兵团第八师农田残膜含量及在土壤中分布情况          下载免费PDF全文

卡那特  张兴瑶  李维军  王辉 《农业工程》2020,10(1):45-47

在新疆生产建设兵团第八师农田进行了残膜样品采集，并对不同采样深度下不同面积的农田残膜含量及数量进行统计分析，获取了土壤中残膜的分布情况，旨在为残膜回收机械的设计以及残膜回收策略的制定提供参考。   相似文献   

Alessandro Bonanno and Lawrence Busch (eds): Handbook of the international political economy of agriculture and food     

Marie Louise Ryan 《Agriculture and Human Values》2018,35(3):731-732

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Bovine spongiform encephalopathy: epidemiological features 1985 to 1990.   总被引：4，自引：0，他引：4  

J W Wilesmith  J B Ryan  W D Hueston  L J Hoinville 《The Veterinary record》1992,130(5):90-94

Following the identification of bovine spongiform encephalopathy (BSE) in the British cattle population in 1986 epidemiological studies were launched. This paper provides an updated account of the epidemiological features of BSE from 1985, when the first cases, based on clinical histories, occurred, until 1990. The number of cases up to December 1989 represents an annual incidence of 3.9 confirmed cases per 1000 adult animals in Great Britain. Many more dairy herds were affected than beef suckler herds, a difference attributable to the difference in feeding practices between the two herd types. The geographical variation in incidence previously described has persisted with the highest incidence in the south and east of England. Other features of the epidemiology, including the low within-herd incidence, remained unaltered from the earlier findings. The results support the previously suggested hypothesis that the outbreak of BSE was due to the sudden exposure of the cattle population to a scrapie-like agent in 1981/82. There was no evidence of direct transmission between cattle during the period considered.  相似文献   

Ovarian follicular characteristics, embryo recovery, and embryo viability in heifers fed high-fat diets and treated with follicle-stimulating hormone.     

D P Ryan  R A Spoon  G L Williams 《Journal of animal science》1992,70(11):3505-3513

Postpubertal beef heifers (n = 55) were used to examine the effects of high-fat diets, independently of energy intake, on nonesterified fatty acid and lipoprotein metabolic patterns, ovarian follicular dynamics, and embryo recovery/viability after FSH superstimulation. High-lipid (HL) diets (5.4% added fat) increased (P < .01) serum concentrations of cholesterol, but not of nonesterified fatty acids, during the 35-d period before FSH treatment. Development of medium-sized (5 to 9.9 mm) follicles was enhanced (P < .05) during this period in heifers fed the HL diet. The HL diet increased total cholesterol (P < .05) and progesterone (P = .14) concentrations in follicular fluid obtained at ovariectomy (n = 10) 60 h after the onset of FSH treatment, but neither estradiol-17 beta nor androstenedione was affected. Granulosa cells recovered from FSH-induced, estrogen-active follicles in heifers fed the HL diet produced greater quantities of progesterone (P = .06) and less estradiol-17 beta (P < .05) in vitro than did granulosa cells from heifers fed the normal lipid diet. Dietary treatment did not influence FSH-stimulated recruitment of medium and large follicles, number of ovulations, embryo recovery, or embryo viability. Data suggest that increments in dietary fat intake can alter specific aspects of ovarian steroidogenic potential and can increase the population of medium-sized follicles theoretically available for maturation and harvest during the estrous cycle. However, conditions that limited the latter process in the current experiment are not understood and require further investigation.  相似文献   

Experimental infection of pregnant gilts with swine hepatitis E virus   总被引：1，自引：0，他引：1       下载免费PDF全文

Chaiyan Kasorndorkbua  Brad J. Thacker  Patrick G. Halbur  Denis K. Guenette  Ryan M. Buitenwerf  Ryan L. Royer    Xiang-Jin Meng 《Canadian journal of veterinary research》2003,67(4):303-306

To determine the effect of swine hepatitis E virus (HEV) infection on pregnant gilts, their fetuses, and offspring, 12 gilts were intravenously inoculated with swine HEV. Six gilts, who were not inoculated, served as controls. All inoculated gilts became actively infected and shed HEV in feces, but vertical transmission was not detected in the fetuses. There was no evidence of clinical disease in the gilts or their offspring. Mild multifocal lymphohistiocytic hepatitis was observed in 4 of 12 inoculated gilts. There was no significant effect of swine HEV on fetal size, fetal viability, or offspring birth weight or weight gain. The offspring acquired anti-HEV colostral antibodies but remained seronegative after the antibodies waned by 71 days of age. Swine HEV infection induced subclinical hepatitis in pregnant gilts, but had no effect on the gilts' reproductive performance, or the fetuses or offspring. Fulminant hepatitis associated with HEV infection was not reproduced in gilts.  相似文献   

Quarantine requirements for the importation of black rhinoceros from Zimbabwe into Australia     

KA DOYLE  BA ROBINSON  DW WILSON 《Australian veterinary journal》1995,72(10):364-368

SUMMARY The proposal by the Zoological Parks Board of New South Wales to import 10 southern black rhinoceros (Diceros bicornis) from Zimbabwe as part of an international project for conservation of the species presented the Australian Quarantine and Inspection Service (AQIS) with a unique challenge. This importation is, at least in the modern era, the first importation of live herbivores from the African continent. Many of the serious animal diseases in the world are endemic in parts of Africa. Knowledge of which of these diseases infect wild species and may be transmitted from the wild species to domesticated species, is limited. This paper describes the strategies adopted by AQIS to facilitate the importation of rhinoceros while maintaining protection of Australian consumers, rural industries, domestic livestock and fauna against the entry and spread of unwanted pests and diseases.  相似文献   

Marked neutropenia in five tumor-bearing cats one week following single-agent vincristine sulfate chemotherapy     

Hahn KA KA  Fletcher CM  Legendre AM 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1996,25(4):121-123

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Flow alteration and thermal pollution depress modelled growth rates of an iconic riverine fish,the Murray cod Maccullochella peelii          下载免费PDF全文

Nick S. Whiterod  Shaun N. Meredith  Paul Humphries  Bradford S. Sherman  John D. Koehn  Robyn J. Watts  Brett A. Ingram  Tom Ryan 《Ecology of Freshwater Fish》2018,27(3):686-698

The serial discontinuity concept (SDC) proposes that hypolimnetic‐releasing impoundments cause major disruptions to the naturally occurring physical, chemical and biological gradients of rivers but that this impact diminishes with distance downstream. Such a gradient in discharge, flow velocity and temperature regime occurs below a large hypolimnetic‐releasing impoundment, the Hume Dam, on the River Murray in south‐eastern Australia. To examine the effects of this disturbance gradient on a warm‐water large‐bodied freshwater fish, the Murray cod (Maccullochella peelii), a bioenergetics model was developed and calibrated to explore energy expended under differing water velocities and temperature regimes. Model simulations predicted negative growth of juveniles directly downstream of the impoundment, due largely to the energetic costs associated with active and, to a lesser extent, standard metabolism outweighing the achievable energetic gains through food consumption. As flow velocity and temperature regimes became more favourable downstream, so did the simulated growth of the species. It was not until +239 km downstream of the impoundment that the model predicted that flow velocity and temperature regimes were suitable for greater weight gains. The modelled growth responses of juvenile Murray cod are consistent with the predictions of the SDC, emphasising that changes in the bioenergetics of individuals are likely to be reflected in reduced growth rates under the changed flow velocity and temperature regimes imposed by disturbance gradients. This research represents a valuable step in the biological understanding of Murray cod within variable riverine environments and emphasises the urgency required to mitigate impacts associated with hypolimnetic impoundments.  相似文献   

Determinants of food security in Tanzania: gendered dimensions of household headship and control of resources     

Ryan Mason  Patrick Ndlovu  John R. Parkins  Marty K. Luckert 《Agriculture and Human Values》2015,32(3):539-549

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Efficacy and nontarget impact of zinc phosphide‐coated cabbage as a ground squirrel management tool     

Roger A Baldwin  Heather Halbritter  Ryan Meinerz  Laura K Snell  Steve B Orloff 《Pest management science》2019,75(7):1847-1854

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