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Ålesund, Norway

Aunsmo A.,Norwegian University of Life Sciences | Krontveit R.,Norwegian University of Life Sciences | Valle P.S.,Kontali Analyse AS | Bohlin J.,Norwegian University of Life Sciences | Bohlin J.,Norwegian Institute of Public Health

Several models for description of fish growth are commonly used in Atlantic salmon farming, including the specific growth rate (SGR), the thermal growth coefficient (TGC), the Ewos growth index (EGI), and average daily weight gain (ADG). In the present study, a subset of a commercial database containing information from 827 fish groups from the year-classes 2000-2005, produced along the Norwegian coastline, was used to validate these four growth models. A number of biotic and abiotic factors were fitted to the models of interest in order to evaluate model strengths and weaknesses and to identify additional factors whose inclusion may improve model performance. Preliminary analysis indicated non-linear relations; to account for this we applied generalized additive models (GAM) in regression analysis. Our findings indicate that ADG was strongly associated with harvest weight and was thus deemed unsuitable for describing growth in Atlantic salmon. SGR was also associated with fish size and biased towards small fish when fish of uneven stocking size were compared. The TGC, SGR and the EGI models were all moderately associated with harvest weight, and the same three models were more strongly associated with mean temperature and mean day-length. These models might therefore present bias when used to compare growth in varying environmental conditions. The EGI was considered the most robust model overall for predicting growth at different sizes exposed to variable abiotic exposure such as temperature and light. Finally, the study suggests that the robustness of growth models can be improved by accounting for non-linear effects on growth and including abiotic factors such as temperature, light, and latitude. © 2014 Elsevier B.V. Source

Muri K.,Norwegian University of Life Sciences | Leine N.,Vennisvegen 950 | Valle P.S.,Norwegian University of Life Sciences | Valle P.S.,Kontali Analyse AS

The Norwegian dairy goat industry has largely succeeded in controlling caprine arthritis encephalitis (CAE), caseous lymphadenitis (CLA) and paratuberculosis through a voluntary disease eradication programme called Healthier Goats (HG). The aim of this study was to apply an on-farm welfare assessment protocol to assess the effects of HG on goat welfare. A total of 30 dairy goat farms were visited, of which 15 had completed disease eradication and 15 had not yet started. Three trained observers assessed the welfare on 10 farms each. The welfare assessment protocol comprised both resource-based and animal-based welfare measures, including a preliminary version of qualitative behavioural assessments with five prefixed terms. A total of 20 goats in each herd were randomly selected for observations of human-animal interactions and physical health. The latter included registering abnormalities of eyes, nostrils, ears, skin, lymph nodes, joints, udder, claws and body condition score. For individual-level data, robust clustered logistic regression analyses with farm as cluster variable were conducted to assess the association with disease eradication. Wilcoxon rank-sum tests were used for comparisons of herd-level data between the two groups. Goats with swollen joints (indicative of CAE) and enlarged lymph nodes (indicative of CLA) were registered on 53% and 93% of the non-HG farms, respectively, but on none of the HG farms. The only other health variables with significantly lower levels in HG herds were skin lesions (P=0.008) and damaged ears due to torn out ear tags (P<0.001). Goats on HG farms showed less fear of unknown humans (P=0.013), and the qualitative behavioural assessments indicated that the animals in these herds were calmer than in non-HG herds. Significantly more space and lower gas concentrations reflected the upgrading of buildings usually done on HG farms. In conclusion, HG has resulted in some welfare improvements beyond the elimination of infectious diseases. The protocol was considered a useful tool to evaluate the welfare consequences of a disease eradication programme. However, larger sample sizes would increase the reliability of prevalence estimates for less common conditions and increase the power to detect differences between the groups. Despite the obvious link between disease and suffering, this aspect is rarely taken into account in the evaluation of disease control programmes. We therefore propose that welfare assessment protocols should be applied to evaluate the merits of disease control or eradication programmes in terms of animal welfare. © The Animal Consortium 2015. Source

Nagel-Alne G.E.,Norwegian University of Life Sciences | Valle P.S.,Kontali Analyse AS | Krontveit R.,Norwegian University of Life Sciences | Solverod L.S.,TINE Mastitis Laboratory
Veterinary Record

The objective of this study was to evaluate the diagnostic performance of two ELISA tests applied to bulk tank milk (BTM) as the first part of a two-step test scheme for the surveillance of caprine arthritis encephalitis (CAE) and caseous lymphadenitis (CLA) infections in goats. The herd-level BTM tests were assessed by comparing them to the test results of individual serological samples. The potential for refining the cut-off levels for BTM tests used as surveillance tools in a population recently cleared of infection was also investigated. Data was gathered on serum (nCAE =9702 and nCLA=13426) and corresponding BTM (nCAE=78 and nCLA=123) samples from dairy goat herds enrolled in the Norwegian disease control and eradication programme 'eHealthier Goats'f. The results showed that the sensitivity and specificity of the CAE ELISA BTM test with respect to detecting .2 per cent within-herd prevalence were 72.7 per cent and 86.6 per cent, respectively. For the CLA ELISA BTM the sensitivity and specificity were 41.4 per cent and 81.7 per cent, respectively, for the same goal of detection. The results suggest that BTM testing can be applied as a cost-effective first step for early detection of CAE and CLA infection. Source

Asheim L.J.,Norwegian Agricultural Economics Research Institute | Hardaker J.B.,University of New England of Australia | Solverod L.,TINE Extension Services | Lindheim D.,TINE Extension Services | Valle P.S.,Kontali Analyse AS
Preventive Veterinary Medicine

The aim of this study was to evaluate the profitability to dairy goat farmers of participating in the Healthier Goats disease control and eradication programme (HG), which was initiated in 2001 and is still running. HG includes the control and eradication of caprine arthritis encephalitis (CAE), caseous lymphadenitis (CLA) and paratuberculosis (Johne's disease) in Norwegian goat herds.The profitability of participation was estimated in a financial cost-benefit analysis (CBA) using partial budgeting to quantify the economic consequences of infectious disease control through HG versus taking no action. Historical data were collected from 24 enrolled dairy goat herds and 21 herds not enrolled in HG, and supplemented with information from a questionnaire distributed to the same farmers. Expert opinions were collected to arrive at the best possible estimates. For some input parameters there were uncertainty due to imperfect knowledge, thus these parameters were modelled as PERT probability distributions and a stochastic simulation model was built.The CBA model was used to generate distributions of net present value (NPV) of farmers' net cash flows for choosing to enroll versus not enrolling. This was done for three selected milk quota levels of 30. 000. L, 50. 000. L and 70. 000. L, and both for before and after the introduction of a reduced milk price for the non-enrolled. The NPVs were calculated over time horizons of 5, 10 and 20 years using an inflation-adjusted discount rate of 2.8% per annum. The results show that participation in HG on average was profitable over a time horizon of 10 years or longer for quota levels of 50. 000. L and 70. 000. L, although not without risk of having a negative NPV.If farmers had to pay all the costs themselves, participation in HG would have been profitable only for a time horizon beyond 20 years.In 2012, a reduced milk price was introduced for farmers not enrolled in HG, changing the decision criteria for farmers, and thus, the CBA. When the analysis was altered to account for these changes, the expected NPV was positive over five years for the 50. 000. L quota, indicating an increased profitability of enrolling in HG.The sensitivity analysis showed that particular attention should be paid to work load and investment costs when planning for disease control programmes in the future. © 2014 Elsevier B.V. Source

To ensure that farm animal welfare issues are identified and addressed appropriately, there is a need for robust on-farm welfare assessment protocols. This paper describes the development of a comprehensive welfare assessment protocol for dairy goats (Capra hircus) and its testing on 30 commercial dairy goat farms in Norway. The protocol combines animal-based welfare indicators with measures of husbandry provisions to enable the identification of welfare problems and challenges inherent to the production system. The study also includes a first report of group level qualitative behavioural assessments (QBA) of goats. Due to reliability and validity issues related to behavioural assessments of human-animal interactions, indices of stockperson attitudes were incorporated as a complementary assessment of stockmanship. The most prevalent physical conditions observed were ocular discharge, skin lesions, udder asymmetry, calluses on knees and hocks, and overgrown claws. Moreover, fear levels appeared to be of particular concern in some herds. Significant associations were found between qualitative behavioural assessments and measures of health and stockmanship. Floor type was associated with four animal-based welfare outcomes. Reliability and validity of goat welfare indicators need to be further tested, and intervention plans and thresholds need to be determined so that advice can be tailored to the specific problems identified on each farm. We conclude that the protocol can work as a tool to identify welfare issues in dairy goat herds, and that this study may be a valuable contribution to the development of a much-needed welfare assessment protocol for dairy goats. © 2013 Universities Federation for Animal Welfare. Source

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