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1.
DB ADAMS JJ LYNCH† BH ANDERSON LR FELL‡ GN HINCH§ RK MUNRO¶ 《Australian veterinary journal》1990,67(12):443-445
Three-year-old, non-lactating and non-pregnant Merino ewes, raised on pasture under a program of strategic treatment with anthelmintic and found to be extremely resistant to "trickle" infection with Haemonchus contortus, were given single-dose infections with either H. contortus or Trichostrongylus colubriformis or both species together. The purpose was to ascertain the intensity of protective immunity against the 2 parasites in sheep with immunity acquired from a presumably slight exposure to infection. To provide a criterion, some infected ewes were immunosuppressed with corticosteroid, dexamethasone. Untreated ewes were extremely resistant to challenge infection with either 15,000 or 150,000 H. contortus or 15,000 T. colubriformis. Surprisingly, when mixed infection was given, egg counts for H. contortus were significantly elevated compared with infection by that species alone. Antibody to antigens from infective larval and adult H. contortus was measured in serum by enzyme-linked-immunosorbent assay (ELISA) during the course of infection. Serum titres against larval antigens were significantly depressed when infections with either H. contortus or T. colubriformis were permitted by immunosuppression with dexamethasone, whereas those against adult antigen were depressed when infection with T. colubriformis was permitted. 相似文献
2.
G. H. BOEREMA R. T. A. COOK J. S. W. DICKENS A. PISI† M. G. BELLARDI† J. E. M. MORDUE‡ 《Plant pathology》1994,43(6):1072-1079
A rust affecting Codiaeum variegatum ('Croton', Euphorbiaceae) imported into the UK from Ivory Coast in 1978 was originally identified as Aecidium codiaei H. Sydow. However, studies on germination of spores, pathogenicity tests and examinations of sori under light microscope and scanning electron microscopy (SEM) revealed that the rust belonged to the tribe Pucciniosireae (a diverse group of mostly tropical microcyclic rust genera characterised by their stages being telescoped into aecidioid telia). Attention was drawn to the transfer of this Aecidium species to Dietelia (a member of the Pucciniosireae) following imports of the disease into the Netherlands from Ghana in 1978. Dietelia codiaei (H. Sydow) Boerema was subsequently confirmed as the causal agent of Codiaeum rust on recent imports into the UK and Italy. It is believed to be distinct from D. emasculata recorded on Breynia , another euphorbiaceous host. 相似文献
3.
The pathogenicity and taxonomy of 15 isolates of Alternaria spp. from pear and apple were compared. Only isolates from Asian pear ( Pyrus pyrifolia ) from Italy and Korea were virulent on leaves and young fruits of the susceptible Asian pear cv. Nijisseiki. Their conidial morphology was typical of A. gaisen (= A. kikuchiana ). Only isolates of A. mali from USA were virulent on susceptible American apple cvs Indo and Red Gold. No virulence was demonstrated in any isolate/host combination among isolates from stem infections of Asian and European pear ( Pyrus communis ), leaf spots of European apple, and ripe fruit rots of Chinese pear ( Pyrus ussuriensis ), European pear and apple. These non-virulent isolates could be readily distinguished from A. gaisen and A. mali by their pattern of branching of conidial chains, the branching associated with A. alternata sensu stricto being most common among non-virulent isolates. This limited survey implies that A. gaisen is only virulent to Asian pear and the toxigenic form of A. mali to certain American apple cultivars; also that A. gaisen is not established outside eastern Asia or the toxigenic form of A. mali outside eastern Asia and parts of USA. 相似文献
4.
RK MUNRO 《Australian veterinary journal》1989,66(2):43-45
The effects of duration of insertion of progesterone releasing devices (PRIDs) on the concentrations of plasma progesterone (plasma P4) and the relationship of these with fertility were examined respectively in ovariectomised and intact Bos taurus cattle. In experiment 1, ovariectomised cows (n = 14) were treated with PRIDs to produce high and low plasma P4 for 7 or 14 days giving 4 treatment groups designated H7, H14, L7 or L14. Mean plasma P4 in the H14 and L14 groups were 6.6 and 6.0 ng/ml respectively, during the first week and 5.4 and 3.8 ng/ml respectively, during the second. Mean plasma P4 of 6.3 and 4.2 ng/ml were observed in H7 and L7. In experiment 2, suckled cows (n = 171) received the same PRID treatments as cows in experiment 1, plus either 375 or 750 iu pregnant mare serum gonadotrophin, and subsequent calving rates were recorded. These were significantly lower after L7 than the other treatments (12% v 38%, P less than 0.025). These results showed that fertility after oestrus was closely related to plasma P4 observed before oestrus and indicated that treatment with progesterone for as little as 1 week can produce normal fertility providing plasma P4 attain a critical threshold during treatment. 相似文献
5.
RK MUNRO 《Australian veterinary journal》1990,67(9):313-315
Twelve suckling and 12 non-lactating post-partum cows were treated with a progesterone-releasing pessary for 7 or 14 d followed by an injection of 500 micrograms oestradiol benzoate (ODB) 24 h after pessary removal or no injection. Suckling had no significant effect on plasma progesterone concentrations (plasma P4) or plasma luteinising hormone concentrations (plasma LH) during pessary insertion. After pessary removal plasma LH rose in response to ODB. The extent of the rise was similar in suckling and non-lactating cows treated with progesterone for 14 d but was significantly lower in non-lactating than suckling cows (P less than 0.025) treated for 7 d. These findings indicate that suckling increases the responsiveness of plasma LH in post-partum cows following progesterone and oestrogen treatment compared to non-lactating cows and that extended treatment with progesterone can remove this difference. 相似文献
6.
KDC STÄRK 《Australian veterinary journal》1996,73(3):96-97
Switzerland has traditionally used a passive disease reporting system for all notifiable diseases. This type of system is not suitable for the documentation of very low prevalences (freedom from disease), sub-clinical cases and non-notifiable diseases. In order to meet the high international standards for animal health surveillance and to fulfil the general need for sound animal health data, Switzerland has evaluated the feasibility of modern monitoring and surveillance concepts. In general, the principle of active surveillance has been acquired and is now being applied whenever possible. In this paper, several examples of Swiss surveillance systems are presented and discussed. They include systematic testing of random population samples, carcase screening at abattoirs and sentinel herd monitoring. 相似文献
7.
Comparative Earth History and Late Permian Mass Extinction 总被引：6，自引：0，他引：6
The repeated association during the late Neoproterozoic Era of large carbon-isotopic excursions, continental glaciation, and stratigraphically anomalous carbonate precipitation provides a framework for interpreting the reprise of these conditions on the Late Permian Earth. A paleoceanographic model that was developed to explain these stratigraphically linked phenomena suggests that the overturn of anoxic deep oceans during the Late Permian introduced high concentrations of carbon dioxide into surficial environments. The predicted physiological and climatic consequences for marine and terrestrial organisms are in good accord with the observed timing and selectivity of Late Permian mass extinction. 相似文献
8.
SUMMARY A case of suspected acute oxalate poisoning is reported in an aged male koala. The animal had extensive renal oxalosis and a haemorrhagic bladder wall when autopsied. The source of the oxalate was not detected. 相似文献
9.
I. GYÜRK 《EPPO Bulletin》1983,13(3):475-478
Spinning disc-atomizers are widely used in seed-dressing machines. They not only give an initial velocity to the droplet but deliver air as well, consequently the droplet enters a moving medium. Computer analysis shows the influence of this mutual motion in the case of linear, parabolic and hyperbolic air velocity decrease. The moving air exerts a significant effect on the ideal encounter zone of liquid and seed. This effect should be taken into consideration in designing the dressing chamber of seed treatment machinery. 相似文献
10.