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排序方式: 共有171条查询结果,搜索用时 15 毫秒
91.
SUMMARY The response of sheep to a recombinant multivalent footrot vaccine containing pilus antigens was examined after the administration of two doses of vaccine at Intervals ranging from 2 to 52 weeks. Agglutinating antibody titres were measured 3 weeks after the second vaccination and showed that lengthening of the interdose interval results in higher agglutinin titres. The capability of sheep to mount an increasingly strong immune response as the interval between doses is increased provides an opportunity to maximise the usefulness of vaccination by administering the first dose well before an expected footrot transmission period. This advantage of increasing the interdose interval has not been reported for traditional, whole-cell footrot vaccines, and use of the new pilus vaccine in this manner may improve prospects for disease control. Furthermore, sheep given a third dose either 6 or 12 months after their initial two-dose vaccination program achieved significantly higher titres than those elicited after the second dose, suggesting the likelihood of further improvement in disease control in successive seasons. 相似文献
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The presentation, treatment and outcomes of 33 ingluvial fibrous foreign bodies in cockatiels (Nymphicus hollandicus) are described. Vomiting, lethargy and weight loss were the most common presenting signs. Diagnosis was made on palpation of a mass in the crop (ingluvies). Both surgical and non‐surgical treatment regimens were evaluated. The overall mortality rate was 33%, suggesting fibrous materials are not safe for cockatiels to groom or ingest and should not be offered as cage accessories. 相似文献
96.
Santos MH Moraes EP Bezerra FQ Moura RT Paula-Lopes F Neves JP Lima PF Oliveira MA 《American journal of veterinary research》2007,68(5):561-564
OBJECTIVE: To define the optimum period for sexing of Saanen goat fetuses by use of transrectal ultrasonography. ANIMALS: 82 Saanen goats pregnant with 124 fetuses. PROCEDURES: Fetal sexing was performed on the basis of the final location of the genital tubercle or identification of external genitalia. In experiment 1, fetuses (n = 78) were monitored every 48 hours from days 40 to 60 of gestation, whereas for experiment 2, 46 fetuses were examined only once between days 47 and 77 of gestation. RESULTS: For experiment 1, accuracy of fetal sexing was 20 of 20 (100%) for a single fetus, 39 of 42 (92.8%) for twin fetuses, and 10 of 16 (62.5%) for triplet fetuses. Diagnostic accuracy was significantly lower for triplet fetuses than that for single or twin fetuses. Final location of the genital tubercle was detected between 45 and 55 days of gestation (mean +/- SEM, 48.9 +/- 1.8 days). For experiment 2, accuracy of fetal sexing for a single fetus (24/24 [100%]) was significantly higher than the accuracy for twin fetuses (16/22 [72.7%]). Considering all fetuses that were born, accuracy of diagnosis was 69 of 78 (88.4%) for experiment 1 and 40 of 46 (86.9%) for experiment 2. Accuracy did not differ significantly between experiments. CONCLUSIONS AND CLINICAL RELEVANCE: Real-time ultrasonography after day 55 of gestation is a suitable method for determination of sex of Saanen goat fetuses by observation of the genital tubercle or identification of external genitalia. 相似文献
97.
EJ Steig EJ Brook JWC White CM Sucher ML Bender SJ Lehman DL Morse ED Waddington GD Clow 《Science (New York, N.Y.)》1998,282(5386):92-95
Central Greenland ice cores provide evidence of abrupt changes in climate over the past 100,000 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic, confirming the link between millennial-scale climate variability and ocean thermohaline circulation. It is shown here that two of the most prominent North Atlantic events-the rapid warming that marks the end of the last glacial period and the Bolling/Allerod-Younger Dryas oscillation-are also recorded in an ice core from Taylor Dome, in the western Ross Sea sector of Antarctica. This result contrasts with evidence from ice cores in other regions of Antarctica, which show an asynchronous response between the Northern and Southern Hemispheres. 相似文献
98.
Rodrigo Egydio Barreto 《Fish physiology and biochemistry》2017,43(1):193-201
In this study, I show that mianserin, a chemical with serotonin and adrenoceptor antagonist activities, increases fish vulnerability to a potential predator threat, when prey fish must deal with this threat based on conspecific chemical alarm cues. For that, I evaluated whether mianserin, diluted in the water, influences the behavioral responses of Nile tilapia (Oreochromis niloticus) to conspecific skin extract (chemical alarm cues). I found that, while mianserin did not abolished antipredator responses, this drug mitigates some components of this defensive reaction. Thus, a potential decrease in serotonin and adrenergic activities reduces the ability of dealing with predators when perceiving conspecific chemical alarm cues. 相似文献
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Paula Menna Barreto Dias Bernadette Julier Jean-Paul Sampoux Philippe Barre Miguel Dall’Agnol 《Euphytica》2008,160(2):189-205
The NPGS-USDA core collection with 85 accessions of red clover, an important forage species, is little described. The goal
of the present study was to evaluate the diversity of a set of accessions from the core collection at the morphological and
molecular level in order to extract some valuable accessions for Brazilian red clover breeding programs. Twenty-one morphological
traits, collected in field and greenhouse in South Brazil, and seven SSR markers were used to describe 57 accessions from
the U.S. core collection and one population cultivated in Southern Brazil. Variation between accessions was large for most
of the 21 morphological traits. A cluster analysis based on the morphological traits revealed five distinct clusters that
separated the populations according to flowering earliness, as already described, but also according to persistency, growth
habit and dry matter productivity. Over seven SSR loci, the number of alleles averaged 11.1 alleles per locus. Genetic diversity
measured with SSR markers was high, with a mean expected heterozygosity of 0.86. An analysis of molecular variance revealed
that the largest proportion of variation (83.6%) resided at the within population level. Although the molecular markers also
separated accessions into five clusters, there was no coincidence between the composition of groups found with morphological
and molecular data. Use of genetic diversity in breeding programs requires to use the most promising populations, to combine
positive traits such as persistency and forage yield, and probably to use within population variation to detect valuable genotypes
that could be used as parents of synthetic varieties. 相似文献