A 24‐day‐old Friesian colt died suddenly and a physical examination the morning the foal died showed no abnormalities and serum IgG levels >8.0 g/l. Necropsy examination revealed haemopericardium and a 2 cm transverse tear at the root of the aorta. The foal was also found to have Chlamydophila spp. in the epithelium and Balantidium coli on the mucosal surface of the large colon. An aortic rupture is a novel finding in a foal, colonic Chlamydiosis has not been previously reported in horses and Balantidium coli has not been reported in equids in North America. 相似文献
All possible tools need to be marshalled for marine fish conservation. Yet controversy has swirled around what role, if any, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) should play for marine fishes. This paper analyses the relevance and applicability of CITES as a complementary tool for fisheries management. CITES currently regulates the international trade of very few marine fish species, by listing them in its Appendices. After the first meeting of the Parties (member countries) in 1976, no new marine fish taxa were added to the CITES Appendices until 2002, when Parties agreed to act to ensure sustainable and legal international trade in seahorses (Hippocampus spp.) and two species of sharks. Progress has continued haltingly, adding only one more shark, humphead wrasse (Cheilinus undulatus) and sawfishes by 2012. Parties voice concerns that may include inadequate data, applicability of CITES listing criteria, roles of national fisheries agencies, enforcement challenges, CITES' lack of experience with marine fishes, and/or identification and by‐catch problems. A common query is the relationship between CITES and other international agreements. Yet all these arguments can be countered, revealing CITES to be a relevant and appropriate instrument for promoting sound marine fisheries management. In reality, Parties that cannot implement CITES effectively for marine fishes will also need help to manage their fisheries sustainably. CITES action complements and supports other international fisheries management measures. As CITES engages with more marine fish listings, there will be greater scope to analyse its effectiveness in supporting different taxa in different contexts. 相似文献
Tropical forests are disappearing at an alarming rate. In Central America, a hectare of forest is cleared for agriculture every 5 min. This study was conducted in a forested 4,000 ha watershed of central Honduras to find deforestation causes based on socio-economic characteristics of population. First, a multitemporal analysis of Landsat TM imagery was conducted to determine deforestation rates and agricultural–forest boundaries. A GIS buffer procedure allowed determining which households were at the deforestation front and which households were located at the rest of the area (control). GIS techniques were used to extract biophysical information such as slope, elevation, land cover, temperature, precipitation, etc. Then, we set up a data base with more than 50 socioeconomic variables (level of education, income, children per family, major economic activity, use of conservation practices, etc.). Around 500 households, distributed all over the watershed, were visited, interviewed and GPS-located. A multivariate statistical analysis allowed an exploratory analysis to eliminate non useful and redundant variables and then to determine what variables appear to be important predictors of deforestation behavior among rural families. A resulting logistic regression model showed that household with lower annual income heads and with less use of conservation practices were more statistically prone to clear the forest (α = 0.001). The study uncovered the complexity of this problem and confirmed the need of using GIS–remote sensing techniques to combine socioeconomic and environmental data in several time–space dimensions to find the causes and trends of tropical deforestation. 相似文献
During the 1990s, the Government of Peru began to aggressivelyprivatize agriculture. The government stopped loaning money to farmers' cooperatives and closed the government rice-buying company. The government even rented out most of its researchstations and many senior scientists lost their jobs. As part of this trend, the government eliminated its seed certification agency. Instead, private seed certification committees were set up with USAID funding and technical advise from a US university. The committees were supposed to become self-financing (bycertifying seed grown by small seed producers) and each committee was supposed to encourage the development of a group of small seed-producing firms, clustered around the seedcertification agency. The amazing thing is that many of the seed committees actually accomplished these goals. The agronomists who staffed the committees stood by their jobs,even after US funding ended, even though the committees' income was (at best) modest, and occasionally under the threat of violence from the extreme left. Some seed certificationcommittees failed and others did not. Some of the problems with Peruvian agricultural liberalization can be seen in regard to the seed programs of maize, rice, potatoes, and beans. For example, the government abandoned most research, yet could not resist creating certain distortions in the seed market (e.g.,buying large amounts of seed and distributing them for political ends). 相似文献
In this study, we describe a method to quantify the transmission of Classical Swine Fever Virus (CSFV) between herds from data collected during the 1997–1998 epidemic in the Netherlands. From the contacts between infected herds and the serological findings shortly before depopulation, we estimated the week of virus introduction and the length of the period over which the herd emitted virus for each CSFV-infected herd. From these data, we estimated the infection-rate parameter β (the average number of herds infected by one infectious herd during one week) and the herd reproduction ratio, Rh (the average total number of secondary outbreaks caused by one infectious herd, i.e. in its entire infectious period), using a SIR-model for different sets of CSF control measures. When Rh > 1, an epidemic continues to grow. On the other hand, when Rh < 1 an epidemic will fade out.
During the phase before the first outbreak was diagnosed and no specific measures had been implemented, β was estimated at 1.09 and Rh at 6.8. In the subsequent phase infected herds were depopulated, movement restrictions were implemented, infected herds were traced forward and backward and the herds in the protection and surveillance zones were clinically inspected by the veterinary authorities (regional screening). This set of measures significantly reduced β to 0.38. However, Rh was 1.3 and thus still >1. Consequently, the number of outbreaks continued to grow. After a number of additional measures were implemented, the value of Rh was reduced to 0.5 and the epidemic came to an end. These measures included pre-emptive slaughter of herds that had been in contact with infected herds or were located near an infected herd, increased hygienic procedures, replacement of transports of pigs for welfare reasons by killing of young piglets and a breeding ban, and regional screening for CSF-infected herds by local veterinary practitioners. 相似文献
Tropical Animal Health and Production - This study aimed to verify the reproductive seasonality in Saanen goats from distinct parity orders (nulliparous, primiparous, and pluriparous) throughout an... 相似文献
To determine whether turkey herpesvirus (HVT) impairs the aspecific and specific defense against an avian pneumovirus (APV) infection, specific-pathogen-free turkeys were inoculated at 7 days of age with HVT and 1, 5, or 7 wk later with APV. Clinical signs, APV replication, and development of antibodies against APV were evaluated. No differences were found between the birds that received both HVT and APV and those that received only APV. 相似文献
When quinoa, Chenopodium quinoa Willd., is cultivated in South America outside of its Andean origin, the heteropterans Liorhyssus hyalinus (Fabricius) and Nysius simulans Stål may emerge as important pests. Here we studied the development and reproduction of both species at different constant temperatures in the laboratory. Egg and nymphal development were investigated at 18, 22, 26, 30, 34, and 36°C. For both species, egg incubation time significantly decreased as the temperature increased. Nymphs did not successfully develop at 18°C and the total nymphal time significantly decreased as the temperature increased from 22 to 36°C. Based on a linear day-degree (DD) model, the lower developmental threshold (LDT) temperatures for eggs and nymphs were estimated to be 16.0 and 17.9°C for L. hyalinus, and 16.1 and 19.7°C for N. simulans, respectively. Thermal requirements for egg and nymphal development were 68.6 and 114.8 DD for L. hyalinus, and 77.7 and 190.3 DD for N. simulans, respectively. Reproduction and adult longevity were studied at 22, 26, 30, and 34°C. For both species preoviposition time decreased as temperature increased, and the oviposition period was longest at 26°C. The highest fecundity and egg viability were observed at 30°C, whereas longevities were higher at 22–26°C than at 30–34°C. As the lowest tested temperatures were not suitable to both heteropterans and 30°C was found to be the optimal temperature for development and reproduction, peak densities are expected in warm areas and seasons. 相似文献
In this paper we report on an outbreak of reovirus, herpesvirus (Pacheco disease), and/or mycosis infection (Aspergillus spp. and Zygomyces spp.) affecting a batch of young African grey parrots (Psittacus erithacus), with 80% morbidity and 30% mortality. Study material was taken from five birds (four dead and one euthanatized) with a range of clinical symptoms (depression, diarrhea, respiratory symptoms). Diagnosis was confirmed by immunohistochemical detection of avian reovirus, electron microscopy, and virus isolation. Viral antigen of reovirus was detected mainly in large mononuclear cells in the bursa of Fabricius and the spleen, pancreas epithelial cells, and circulating cells; lymphoid organs displayed the largest number of immunopositive cells and severe lymphocyte depletion. Bacteriologic study was negative. Reovirus infection was common in all birds studied, whereas Pacheco disease and mycosis were found in only some, suggesting that reovirus could be the initial cause triggering the outbreak and facilitating infection by other agents and their swift spread through the batch. 相似文献