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1.
Serum antibody (virus neutralisation, complement fixation, IgM and IgG) responses to equine herpesvirus-1 (EHV-1) infection were measured in six foals which were initially free from EHV-1 and EHV-4 infection and maternally-derived antibodies. Following primary infection, high titres of virus neutralisation and complement fixation antibodies were detectable against EHV-1, however, corresponding antibody levels against EHV-4 were low or inapparent, although the two viruses share a number of cross-reactive epitopes. In addition, following the primary infection with EHV-1, IgM levels increased before those of IgG, virus neutralisation and complement fixation antibodies, peaked sooner and thereafter declined. Stimulation of IgM levels was observed on secondary infection with EHV-1 given 61 days later. In contrast, IgG, virus neutralisation and complement fixation antibodies following primary infection were more sustained and no increase in their levels was observed on secondary infection. No consistent changes in IgM or IgG levels were seen after administration of dexamethasone to reactivate latent virus. 相似文献
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Five Devon cattle with suspected ceroid-lipofuscinosis and aged between 19 and 39 months of age were humanely slaughtered and subjected to post-mortem examination. There was severe atrophy of the cerebrum, particularly of the occipital cortex. Microscopy also showed severe atrophy of the retina with complete loss of photoreceptor cells, even in the youngest animal examined. Histopathologically the disease was characterised by accumulation of a fluorescent lipopigment in neurones, including those of the retina and a severe astrocytosis. The disease, which is characterised by the accumulation of subunit c of mitochondrial ATP synthase, is similar to that extensively described in South Hampshire sheep except that the retinal lesions were more severe. In contrast, tremors were not noted in the cattle. The clinical history and similarity to the disease in sheep and other species indicated inheritance was as an autosomal recessive trait. 相似文献
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A new syndrome, characterised by acute respiratory distress and by abnormalities of the skin, hair and thyroid, was the apparent cause of neonatal death in 35 (24 per cent) of 146 piglets sired by a large white boar in four small commercial pig units. The syndrome appears to be of genetic origin, inherited as an autosomal recessive trait. Its similarities with the respiratory distress syndrome (RDS) of the newborn infant and the "barker" syndrome of the newborn foal are discussed. 相似文献
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Some behavioural and ecological factors affecting distribution,biomass and production of juvenile Atlantic salmon 下载免费PDF全文
R. John Gibson 《Ecology of Freshwater Fish》2015,24(3):397-411
Observations were made in an experimental stream tank (total area 14.7 m2) on juvenile Atlantic salmon, Salmo salar L (parr), relating experimental observations to field observations, including the reported diurnal fasting behaviour of juvenile salmon at water temperatures <10 °C. Densities in the tank ranged from five to twenty parr, at water temperatures ranging from 4.6 °C to 15.8 °C. The wide channel of the stream tank, with mean water velocity of 18.8 cm·s?1, was the preferred section, where territorial behaviour was observed. Biomass was regulated in the wide channel by territorial mosaics or by dominance hierarchies. Dominance hierarchies were reflected in coloration of the fish. Dominant salmon were generally in the wide channel. Densities of salmon parr (of mean fork length 10.2 cm) in the channel ranged from 0.84 m?2 to 1.73 m?2, with an average biomass of 14.2 g·m?2. Growth was least at the 5.9 °C temperature treatment. In experiments at temperatures below 10 °C, feeding, dominance hierarchy and territorial behaviour were observed in daylight hours, contrary to the published literature. Interactions with other species may affect behaviour. Some observations were made on a closely related species, brown trout (Salmo trutta L.), a commonly cohabiting species in many systems. Trout displaced salmon from their preferred locations in the tank and were more aggressive than the salmon, reducing agonistic behaviour by the salmon. The commonest agonistic act shown by salmon was ‘charge’ and that by the trout was ‘approach’. Some field observations affecting behaviour and production are discussed. 相似文献
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Maes D Gibson K Trigo E Saszak A Grass J Carlson A Blaha T 《Berliner und Münchener tier?rztliche Wochenschrift》2001,114(9-10):339-341
This field study investigated the efficacy of a Salmonella Choleraesuis live vaccine (Argus SC) to reduce the number of infections with Salmonella. Twelve groups of about 380 pigs each were randomly allocated to either vaccination (V) or no vaccination (C). The vaccine was applied orally at 3 and 16 weeks. Forty pigs per group were blood sampled at 3, 10, 16, and 24 weeks to detect possible antibodies against Salmonella. The prevalence of Salmonella in the lymph nodes was the major variable. In the V groups, only 0.6% of the lymph nodes were positive, whereas 7.2% were positive in the C groups (p < 0.001). The percentage of seropositive pigs at 24 weeks (cut-off OD > 10) was 26% and 9% in the V and C groups, respectively (p < 0.001). The present study documented that vaccination with a live modified S. Choleraesuis vaccine is a useful tool to lower the prevalence of Salmonella in swine herds. 相似文献
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C. R. Wilson † J. A. deLittle J. A. L. Wong P. J. Schupp L. J. Gibson 《Plant pathology》2005,54(3):393-400
The use of soil-surface applications of finely powdered calcium hydroxide (Ca(OH)2) to inhibit Sclerotinia minor sclerotial germination and infection at the collar region of lettuce plants is described. In the laboratory, a pH > 8·0 reduced sclerotial germination of the three S. minor isolates tested. In the glasshouse, surface applications of 2–10 t Ca(OH)2 ha−1 raised the pH of the top 1–2 cm of a duplex sandy loam soil above 8·5 for at least 8 weeks without affecting soil pH within the transplant root zone. There was a linear relationship between the rate of Ca(OH)2 applied and disease control, with complete disease suppression at 10 t Ca(OH)2 ha−1. In field trials on two soil types (duplex sandy loam, pH 6·0; and red ferrosol, pH 6·9), a rate of 2·5 t Ca(OH)2 ha−1, maintained soil-surface pH above 8·5 for 1–3 weeks and provided up to 58% reduction in lettuce drop. Application of polyvinyl alcohol (a soil-conditioning polymer) over the Ca(OH)2 layer appeared to reduce Ca(OH)2 loss by wind, but did not improve retention of raised soil-surface pH or disease suppression. Ca(OH)2 treatment gave similar disease control to the industry standard treatment of a procymidone-based fungicide seedling drench. A combined treatment of Ca(OH)2 and fungicide drench gave greater control than either individual treatment, and equivalent control to fungicide drench and three procymidone foliar sprays, offering integrated management options. The use of soil-surface-applied Ca(OH)2 with fungicides, rotation and drip irrigation offers an opportunity for enhanced and sustainable control of lettuce drop. 相似文献
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