Prevalence of Neospora caninum and bovine viral diarrhoea virus in dairy cows in Southern Vietnam

The main purpose of this study was to investigate the prevalence of Neospora caninum and bovine viral diarrhoea virus (BVDV) in some dairy herds in Southern Vietnam, and to ascertain whether there were differences in seroprevalences between herds with imported and locally bred cows. Serum samples collected on five state farms and 97 smallholder herds were analysed for the presence of antibodies to N. caninum and BVDV. All BVDV antibody-negative sera were further tested by antigen-ELISA in order to identify persistently infected individuals. The N. caninum prevalence varied between 16% and 53% in the state herds, and was higher in the four herds that had imported cows than in the herd that only had locally bred cows. Nineteen percent of the samples collected on smallholder farms, which all had only locally bred cows, had antibodies to N. caninum. The BVDV seroprevalence varied between 58% and 93% on the state farms. In smallholder herds, the prevalence of BVDV among the sampled cows was 18% and even lower on the state farms. Despite the high seroprevalence for BVDV in the state herds, no persistently BVDV infected cows were found. Given the high prevalence for Neospora and BVDV among herds with imported cows, it seems advisable to test for both infections before cattle are imported into the country.     

Stakeholders' perceptions of consultations as tools for co-management — A case study of the forestry and reindeer herding sectors in northern Sweden

The forestry and reindeer herding sectors utilize the same land in northern Sweden, and adversely affect each other's productivity. The common pool resource character of this situation has made it difficult to find ways to resolve conflicts that could threaten the two sectors' continued co-existence. A consultation procedure that was introduced to reduce conflicts does not appear to be effective, since conflicts between the two actors still occur. One reason for this failure might be found in the power distribution between forestry and reindeer herding. Earlier research has shown that a co-management system in which the allocation of power between the stakeholders is uneven is difficult to maintain in the long term. However, it is unclear just how uneven the power distribution is between the two actors in this case, and the consequences the disparity might have for the viability and stability of the management system. Focusing on the power relations within the consultation procedures, this paper explores the potential of the present institutional system to take the different interests of the stakeholders into account and to use the consultation procedures as tools for co-managing the forest resources in northern Sweden.     

Influence of thermal treatment on black currant (Ribes nigrum L.) juice aroma

The influence of thermal treatment on black currant juice aroma was investigated in temperature and time ranges relevant for black currant juice concentration processes, namely, 45, 60, 75, and 90 degrees C. Forty-nine aroma compounds were quantified, and the thermal treatment resulted in concentration increases of most terpenes, aldehydes, furans, and phenols, whereas the concentration of esters slightly decreased. Higher temperatures and longer exposure times had larger effects on the aroma compounds. Odor triangle tests showed no sensory difference between pasteurized juice and juice heated at 60 degrees C, whereas juice heated at 90 degrees C differed significantly from pasteurized juice. It is concluded that a 90 degrees C thermal treatment of black currant juice, which is in the temperature range used for conventional evaporation of black currant juice, has an effect on the aroma and sensory properties.     

Consumption and remediation of European Seabass (Dicentrarchus labrax) waste by the sea cucumber Holothuria forskali

Integrated multi-trophic aquaculture (IMTA) systems combining finfish and sea cucumbers remain largely untested. Integrating a deposit-feeding species into existing aquaculture units prerequires survival of the deposit feeder, waste diet consumption and bioremediation effect of feeding activity. The sea cucumber, Holothuria forskali, was fed waste from cultured European Seabass, Dicentrarchus labrax, to determine palatability and impact of grazing by H. forskali. Sea cucumbers readily consumed waste diet at amounts suitable to process biodeposition beneath commercial sea-based D. labrax farms. Grazing by H. forskali significantly reduced total nitrogen content of D. labrax waste in short-term controlled feeding experiments (unpaired t test, p < 0.05) and suppressed total carbon content of D. labrax waste in long-term controlled feeding experiments (unpaired t test, p < 0.05). Survival, palatability and nutrient reduction results support investigation of H. forskali inclusion in IMTA systems focussed on bioremediation of finfish waste if limitations in understanding of growth potential, biology and life history are addressed.     

Artificial neural networks as a tool for plant identification: a case study on Vietnamese tea accessions

Seventeen tea accessions belonging to Chinese (Camellia sinensis), Assamic (C. sinensis var. assamica), and Shan tea (C. sinensis var. pubilimba) groups, which are either commercially planted or new promising tea germplasm, were morphologically described at Phu Tho province (Viet Nam) and assessed for their diversity. Fourteen phyllometric parameters were qualitatively and quantitatively investigated using digital image analysis. The accessions were then discriminated by a dedicated artificial neural network for univocal plant identification and a hierarchical cluster analysis was performed in order to build a dendrogram reporting the relationships among them. Results proved the diversity of investigated tea morphotypes from Phu Tho province based on a morphological screening. More, the artificial neural network was able to perform a correct identification for almost all the accessions using simple dedicated instruments.     

Prevalence and transmission of Neospora caninum within infected Swedish dairy herds

In this long-term study, the changes in within-herd Neospora caninum seroprevalences and the relative importance of horizontal and vertical parasite transmission in Swedish dairy herds were investigated. The within-herd prevalences varied between 5.8% and 65.0% when the herds were first sampled. Comparing the prevalences of year 2000 with those found 2-3 years later, nine out of 14 investigated herds had a similar or lower within-herd prevalence while five herds had an increased portion of seropositive individuals. Three herds were free or almost free from infection at their last sampling. Changes in prevalence were not related to the level of prevalence that each herd had when first sampled. Antibody avidity measurements revealed that the majority of seropositive individuals in all herds were chronically infected. Dam-calf pair investigations and inspection of genealogic trees supplemented with antibody test results showed that vertical transmission was by far the dominant transmission route in all herds. Taken together, these results indicate that the prevalence of N. caninum infection in Swedish dairy cattle can be successfully reduced if actions to eliminate infection in a herd are combined with preventive measures to avoid re-infection.     

Assessment of antibody avidity in aborting cattle by a somatic Neospora caninum tachyzoite antigen IgG avidity ELISA

A Neospora caninum IgG avidity ELISA was carried out on the basis of a somatic N. caninum tachyzoite antigen. The test was validated using experimentally infected calves, where a clear maturation of the IgG avidity over time could be demonstrated. At a maximum of 82 days after infection (d.p.i.), all animals showed antibody avidities ranging above 35%, and respective sera were thus defined as highly avid.Sera of 103 naturally infected seropositive cows with abortion (N. caninum association was provided by a N. caninum PCR-positivity of the fetus in 40 cases) and 139 seropositive animals without abortion history were concurrently examined. Significantly lower avidities were observed in aborting cows when compared to animals without abortion problems (P<0.01). While the avidity of sera collected before abortion remained practically constant until abortion, a significant increase of avidity could be observed in samples collected weeks to months after abortion (P<0.01).The avidities of non-aborting animals from farms with or without abortion problems did not differ significantly with time and were mainly located in the high avidity area. These data indicate that low avidities are not necessarily linked to recent N. caninum infection but can also be an indicator for increased abortion risk in cattle.     

Use of bulk milk for detection of Neospora caninum infection in dairy herds in Thailand

The relationship between the level of Neospora caninum antibodies in bulk milk and the seroprevalence in lactating cows was investigated. Bulk milk was also used to estimate the prevalence of N. caninum infection in dairy herds in the northeast and north Thailand. Bulk milk and individual serum from all lactating cows in 11 herds as well as 220 bulk milk samples from nine milk collection centres were analysed for presence of N. caninum antibodies using an iscom ELISA. In the 11 herds the bulk milk absorbances ranged between 0.04 and 0.89 and the seroprevalences varied between 0 and 46%. Five herds had milk absorbances below 0.20, among those were the two herds housing only seronegative lactating cows. In the remaining three herds with such low bulk milk absorbances one or two cows (5-14%) were seropositive. Six of the investigated herds had bulk milk absorbances above 0.20. In the two herds with the highest bulk milk absorbances more than 30% of the cows were seropositive. Using an absorbance of 0.20 to discriminate between negative and positive herds, 102 (46%) of 220 bulk milk samples were judged positive. There was no significant difference in mean bulk milk absorbance between the milk collection centres within each region. However, the proportion of herds with bulk milk absorbances > or =0.50 in the north was statistically (P < 0.01) higher than that in the northeast. It was concluded that bulk milk antibody testing can be used to identify N. caninum-infected herds and that N. caninum is a common infection in dairy herds in Thailand.