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排序方式: 共有398条查询结果,搜索用时 312 毫秒
71.
Duscher R Duscher G Hofer J Tichy A Prosl H Joachim A 《Veterinary parasitology》2011,178(3-4):273-278
In this study 595 lactating cows originating from 31 carinthian farms were investigated in accordance of liver fluke infection using individual and tank milk as well as individual blood and faecal samples. Two commercial ELISAs were used to test the milk and blood serum, and the results were compared with coproscopy and a commercial copro-antigen ELISA. Receiver operating characteristics (ROC) and two-graph operating characteristics (TG ROC) of tank milk results were conducted based on the individual milk to determine the minimum reliable in-herd antibody prevalence for the predominant condition in the investigation area. In 17.8% of the examined individuals located in 64.5% of the farms eggs were detected by coproscopy. The copro-antigen ELISA delivered 13.4% positive individuals from 54.8% of the farms. The milk ELISAs showed 42.7% (Euroclone) and 44.2% (Pourquier) positive cows on 90.3% of the farms. The blood samples were positive in 43% (Euroclone) and 45.2% (Pourquier) of the individuals from 90.3% to 96.8% of the herds, respectively. Based on the milk and the blood an average in-herd prevalence of 30-45% can be assumed. The serum and milk samples delivered correlating results with kappa values between 0.94 and 0.97, whereas the coproscopy and copro-antigen ELISA did not correlate well with the ELISA results. The two different ELISA tests highly correlated on individual and on herd level. Both showed a reliable minimum in-herd prevalence of ~20%, meaning that one fifth of the individuals in a herd have to be positive to obtain a positive bulk tank milk result. In the investigated area a higher in-herd prevalence is expected, therefore the tank milk is useful as a monitoring tool and can be used as a basis for intervention strategies. 相似文献
72.
Michl J Modarai M Edwards S Heinrich M 《Journal of agricultural and food chemistry》2011,59(18):10388-10393
Identification of toxic or harmful agents continues to be a key goal in agricultural chemistry. This paper reports a metabolomic analysis of Ranunculus repens and related species, which were recently postulated to be cocausative agents in the etiology of equine grass sickness (EGS). Specifically, samples collected at EGS sites were compared with those from non-EGS sites. Furthermore, interspecific and seasonal variations and the species' response to edaphic and climatic factors were investigated. (1)H NMR spectroscopy in combination with multivariate data analysis was applied to the crude methanol extracts of the Ranunculus samples, as well as their chloroform fractions. Samples from EGS sites were significantly different from control samples. The metabolite composition varied greatly between different Ranunculus species. No significant changes could be observed between samples collected in different seasons. This work provides strong evidence that Ranunculus is involved in the etiology of EGS and has implications for agricultural management of pastures. 相似文献
73.
In this study, we develop and validate multiple regression models to estimate the degree of fruit scarring by citrus thrips, Scirtothrips citri (Moulton), from heat and chill degree days. Regression coefficients indicate that cool weather during early March (2 March–16 March) and warm weather during bloom are associated with high levels of thrips scarring. The biological mechanisms leading to the temperature-fruit scarring relationships are unknown. An economic analysis suggests that using model predictions may increase the average financial return per hectare and reduce the number of insecticide treatments applied against citrus thrips. 相似文献
74.
Johann Sölkner Heinrich Grausgruber Ally Mwai Okeyo Peter Ruckenbauer Maria Wurzinger 《Euphytica》2008,161(1-2):273-282
Breeding objectives always involve consideration of multiple traits, even in situations where output of a single trait is
dominant. We review literature dealing with formal definition of breeding objectives. Involvement of farmers in the process
of setting up breeding objectives is also considered. In the optimal selection index, the relative importance of a trait is
scaled by its economic value, derived as marginal profit related to a change in expression of defined size. Normative approaches
to derive economic values use partial derivatives of a profit equation with respect to the traits involved or model the bio-economic
system with various techniques. The theory is well developed and includes consideration of non-linear profit functions and
traits with an intermediate optimum. It is frequently applied in animal breeding. In dairy cattle breeding, a major change
of focus from traits related to output (i.e., milk yield) to traits related to cost of input (health, fertility, feed efficiency)
has taken place recently. Plant breeders find the concept of deriving relative economic weights of traits difficult to apply
and often replace the optimal index by restricted or desired gains indices. A change of paradigms similar to that in cattle
breeding seems advisable. Participatory approaches to evaluate the relative importance of traits are more frequently applied
in plant breeding than in animal breeding. We review two studies, dealing with methods of acquiring information about selection
criteria of farmers planting maize in the Ethiopian highlands and of pastoralists keeping cattle in Uganda, in detail. 相似文献
75.
Franziska Löschenberger Andreas Fleck Heinrich Grausgruber Herbert Hetzendorfer Gerhard Hof Julia Lafferty Marion Marn Anton Neumayer Georg Pfaffinger Johann Birschitzky 《Euphytica》2008,163(3):469-480
Breeding for organic agriculture (BFOA) is a strategy for a commercial breeding company based on the exploitation of the frequently
observed high correlation for many traits between conventional, low input (LI) and organic agriculture (ORG). Indirect selection
under LI can be useful to roughly divide the germplasm into the genotypes better adapted to high input and those better adapted
to LI or ORG conditions. BFOA is an evolving process, in which two methods are currently applied: early generations are either
selected following the pedigree system under LI, or grown as bulk populations on ORG fields. In the latter case the system
switches to LI after individual ear selection under ORG conditions. In both methods, the first replicated yield trial is grown
parallel under ORG and LI. Subsequently, the genotypes are grouped into conventional or ORG advanced trial series. The BFOA
strategy allows that the larger genetic variability of both the organic and conventional gene pool can be exploited in the
selection for ORG. Hitherto, seven winter wheat varieties were released in Austria after exclusive organic VCU testing. 相似文献
76.
The Rysto gene from Solanum stoloniferum introduced into potato cultivars (Solanum tuberosum L. ssp. tuberosum) confers resistance to potato virus A, potato virus V and potato virus Y (PVY). In addition to PVY, tobacco etch virus (TEV) and a TEV construct that encodes β‐glucuronidase (TEV‐GUS) were inoculated to determine the inheritance of resistance to these viruses in progenies obtained from potato cultivars containing the Rysto gene. While cultivars ‘Karlena’ and ‘Delikat’ were susceptible, ‘Bettina’ and clone 927eY were resistant to PVY, TEV and TEV‐GUS, as determined by enzyme linked immunosorbent assay, biotest and GUS assay, respectively. The segregation ratios obtained from the progenies of ‘Bettina’בDelikat’ and 816eY בKarlena’ indicate that resistances to PVY and TEV are governed by one dominant gene or two genes tightly linked in coupling phase. Evidently, Rysto confers broad spectrum resistance to potyviruses. TEV resistance could be reliably detected 4 days after inoculation with the TEV‐GUS construct by GUS assay. Therefore, the GUS‐tagged TEV construct can be used for early selection for resistances based on the gene Rysto or closely linked genes. 相似文献
77.
Dr. Heinrich Dathe 《Journal of pest science》1951,24(7):105-106
Ohne Zusammenfassung 相似文献
78.
Heinrich Müller 《Journal of pest science》1941,17(11):121-125
Ohne Zusammenfassung
Mit 8 Abbildungen 相似文献
79.
Dr. Heinrich Härdtl 《Journal of pest science》1941,17(4):43-47
Ohne Zusammenfassung 相似文献
80.