The objective of the work presented in this thesis was to develop valid, reliable and feasible indicators for the on-farm assessment of sheep welfare. In the absence of a reference test for animal welfare assessment, the welfare indicators in this thesis were developed within the Farm Animal Welfare Council( FAWC) Five Freedoms framework. A scientific literature review and the consensus opinion of a panel of experts were used to judge the face and consensual validity of a selection of indicators of sheep welfare. Experts identified 193 current on-farm welfare issues for sheep and subsequently suggested a range of animal- (n = 26), resource-( n = 13) and management-based indicators( n = 22) in order to assess the on-farm welfare of adult sheep( > 1 year-old), growing lambs (> 6 weeks -<I year-old) and young lambs (< 6 weeks-old). The diagnostic validity of 49 non-invasive, animal-based indicators was tested during a cross-sectional study in which 8 observers independently assessed the indicators on 4686 sheep and lambs from 50 farms in England and Wales. This study found that many indicators, including measures of lameness, body condition, and cleanliness, were reliable, sensitive and specific between observers of differing occupations and levels of training and experience. The measures were also feasible to apply and capable of detecting between-farm variation in conditions associated with sheep welfare. Studies in the use of qualitative behaviour assessment (QBA) also found good levels of reliability for observer assessments of video-clips of sheep behaviour. The ability of animal-based indicators to detect seasonal variation in sheep welfare conditions was investigated on 5740 adult sheep and growing lambs from 12 sheep farms during a one-year longitudinal study. Animal-based indicators including measures of lameness, body condition and QBA, were found to be capable of detecting seasonal variation, suggesting that the tests were valid under different management conditions and across the different events of the annual sheep production cycle. Overall, a low proportion of the sample population was observed with conditions that affected sheep welfare, which may have been the result of non-random sampling of farms. However, for the purposes of this thesis the ability of the indicators to detect important welfare conditions at a low prevalence provide further evidence of their validity. Resource-based assessments were feasible to perform but assessments were limited to certain periods of the production cycle. As management-based indicators relied on the accuracy of farmer interviews and access to farm records, the use of animal-based measures may be a more appropriate means of assessing some aspects of flock welfare. A final set of valid, reliable and feasible indicators of sheep welfare, comprising 28 animal- and II resource- and management-based measures, was recommended on the basis of field validation results and expert opinion. Key animal-based indicators that were found to be reliable, responsive and robust under extensive and intensive farming systems and suitable for assessing both sheep and lambs were lameness, demeanour and body condition. It is suggested that these indicators should be applied in future on-farm protocols by trained assessors who are calibrated to the StandardO Operating Procedures (SOP's). The interpretation of animal-based indicator assessments was guided by expert opinion in the form of preliminary cut-off points, which defined the level of acceptable and unacceptable flock welfare. As a result, the work presented in this thesis can inform the method of assessment and interpretation of a selection of valid, reliable and feasible on-farm indicators of sheep and lamb welfare.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:540031 |
| Date | January 2011 |
| Creators | Phythian, Clare Joan |
| Publisher | University of Liverpool |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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