A consensus of expert opinion was used to provide both face and consensual validity to a list of potential indicators of sheep welfare. This approach was used as a first step in the identification of valid welfare indicators for sheep. The consensus methodology of the National Institute of Health, using pre-meeting consultation and focus group discussions, was used to ascertain the consensus opinion of a panel of sheep welfare experts. The Farm Animal Welfare Council's five freedoms were used as a framework to organise a list of current on-farm welfare issues for sheep. The five freedoms were also the welfare criterion used to identify potential on-farm welfare indicators for sheep. As a result, experts identified 193 welfare issues for sheep and lambs managed on farms across England and Wales. Subsequently, a combination of animal-(n 5 26), resource-(n 5 13) and management-(n 5 22) based indicators was suggested for (i) adult rams, (ii) adult ewes (male and female sheep, over 1 year old), (iii) growing lambs (male and female sheep, over 6 weeks to 1 year old) and (iv) young lambs (male and female lambs, 6 weeks old and under). The results from this study could therefore be used to inform the further development of valid methods of assessing the on-farm welfare of sheep.

Digital dermatitis (DD) is an infectious lameness commonly found in dairy cattle worldwide, and it is known as bovine digital dermatitis (BDD) or papillomatous digital dermatitis (PDD). The disease was first reported in 1980 in the United States (1) and in the late 1980s in the United Kingdom (2). BDD has also been confirmed in beef cattle (3, 4), and over the last 30 years, the disease has been recognized as an important cause of bovine lameness (5).Lameness in cattle and sheep has serious animal welfare and economic implications (6-9). The effects of lameness in cattle include a decrease in milk yield (9, 10) and fertility (8, 11-13) and an increase in rate of culling (12,14). This has been found to be particularly true for cattle suffering from BDD (8, 15, 16) with a recent study of the cost of lameness in the United States estimating that on average, BDD costs $133 per case (17).BDD is now a worldwide problem, and controlling BDD on dairy operations has proven difficult. Moreover, in the last 20 years, sheep in the United Kingdom have been identified with a form of DD termed contagious ovine digital dermatitis (CODD), which is rapidly emerging as a severe infectious foot disease since it was first reported in the United Kingdom in 1997 (18-20). Now, CODD has spread into the Republic of Ireland (20), and it was recently reported in dairy goats in the United Kingdom (21), indicating further cross-species transmission. The contagious nature of DD is also evident by the reports of a manifestation of the disease in a wildlife host, North American elk (Cervus elaphus) from Washington State (22). The reports of DD in previously unaffected species, including U.S. wildlife, suggests a much greater global threat of the disease than previously considered.BDD in cattle manifests in several forms, but most frequently as an ulcerative lesion of the digital skin located immediately above the coronary band between the heel bulbs which results in severe lameness (23). The clinical features of CODD in sheep are slightly different, mainly because the initial lesion site on the sheep foot is different. CODD lesions commence at the coronary band and then run under the hoof horn capsule dorsally and abaxially (24). CODD frequently presents a particularly severe outcome where the whole horn capsule can be lost (18,(25)(26)(27). As a result of the severity of the lesions, sheep can be extremely lame, impacting the welfare of the affected sheep (28). This is concurrent with the lesion pathology identified in elk, described as erosive lesions on

Contagious ovine digital dermatitis (CODD) is a cause of severe lameness in sheep in the UK currently affecting approximately 50% of farms. Six farms were studied in North Wales to investigate (1) the prevalence dynamics of CODD, (2) the association between sheep with CODD and potential risk factors and (3) the impact of CODD on lameness in sheep. The farms were visited at approximately two-month intervals between June 2012 and October 2013 and 6515 sheep were examined. The mean sheep level prevalence of CODD varied between farms (2.5-11.9%). Within farms, prevalence may increase in the late summer/early autumn and after housing. Environmental risk factors included larger flocks, lowland pasture, lush pasture and poached pasture. Co-infection of a foot with footrot was strongly associated with CODD in that foot (OR: 7.7 95% CI: 3.9-15.5 P<0.001) but negatively associated with co-infection of a foot with interdigital dermatitis (OR: 0.04 95% CI: 0.02-0.1 P<0.001). Reinfection with CODD was observed in 78 individual sheep but there was no re-infection at foot level. Lameness on all farms reduced during the study and seasonal changes in lameness followed similar patterns to those for CODD. Infection with CODD leads to a greater increase in locomotion score compared to footrot or interdigital dermatitis and CODD lesion grade was strongly associated with being lame. Sheep with CODD in more than one foot were more likely to be lame (OR: 25.0 95% CI: 12.5-49.9 P<0.001) than those with just one foot affected (OR:10.0 95% CI: 8.6-11.6 P<0.001). The biggest risk factor for CODD is co-infection with footrot and therefore control of footrot should help reduce the risk of CODD on affected farms. Furthermore environmental risk factors for CODD are similar to those for footrot adding weight for control strategies that target both diseases in tandem. The routine repeated gathering of sheep for the purposes of treating all lame sheep might be an effective control strategy for lameness on some sheep farms. Effective systemic immunity to CODD in sheep appears to be lacking, as 78 sheep were observed to be re-infected with CODD during the survey. However, there is epidemiological evidence that there may be some local immunity within the foot warranting further investigation.

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Footrot and contagious ovine digital dermatitis (CODD) are common causes of foot disease of sheep in the UK. The study reported here is a split flock randomised treatment trial undertaken on a group of 748 fattening lambs on a UK sheep farm affected by CODD and footrot. The sheep were randomly assigned to one of two treatment protocols. In protocol A, all sheep were given two doses of footrot vaccine (Footvax, MSD), plus targeted antibiotic therapy (long-acting amoxicillin, Betamox LA, Norbrook Pharmaceuticals) to sheep with foot lesions likely to be associated with a bacterial infection. In protocol B, the sheep only received targeted antibiotic therapy. Sheep were re-examined and foot lesions recorded five and nine weeks later. New infection rates in the footrot vaccinated group were lower compared with the vaccinated group for both CODD (18.2 per cent compared with 26.4 per cent, P=0.014) and footrot (12.55 per cent compared with 27.5 per cent, P<0.001). Recovery rates were unaffected for CODD (80.46 per cent compared with 70.97 per cent, P=0.14) but higher for footrot (92.09 per cent compared with 81.54 per cent, P=0.005) in sheep which received the vaccine. On this farm, a footrot vaccine efficacy of 62 per cent was identified against footrot and 32 per cent against CODD infection. An association between a sheep having footrot at visit 1 and subsequently acquiring CODD was identified (odds ratio [OR] 3.83, 95 per cent CI 2.61 to 5.62, P<0.001). These results suggest a role for infection with Dichelobacter nodosus in the aetiopathogenesis of CODD on this farm.

Contagious ovine digital dermatitis (CODD) is an infectious foot disease of sheep causing severe lameness. Diagnosis is currently made using broad anecdotal descriptions. The aim of this study was to systematically and formally describe the clinical presentation of the disease in terms of (1) a lesion grading system; (2) associated radiographic changes and (3) severity of associated lameness. A five-point lesion grading system was developed and applied to 908 sheep affected by CODD from six farms. Sheep with lesions typical of each grade were euthanased and their feet radiographed. Radiographic abnormalities including soft tissue and bony changes were evident in feet with lesions graded 2-5. In order to quantify the welfare impact of CODD, all the 908 sheep were locomotion scored. Five hundred and eighty-five (64.5% (95% CI 61.4% to 67.6%)) were lame. The locomotion score for affected sheep increased with worsening pathological changes. Once healing had begun the locomotion score decreased. In conclusion the five-point grading system may be used to clinically describe stages of CODD lesions. The radiographic changes revealed examples of deeper pathological changes and there was a strong association between the lesion grading system and locomotion score in affected sheep.

Qualitative Behaviour Assessment (QBA) is whole-animal methodology that assesses the expressive qualities of animal demeanour using descriptors such as 'relaxed', 'anxious' or 'content'. This study aimed to examine the inter-observer reliability of 12 fixed-list QBA descriptors for sheep that had been generated in a previous Free-Choice Profiling study by experienced animal welfare inspectors, based on the same video footage used in the current study. The 12 QBA terms were scored by two different assessor groups consisting of two veterinary science students and four veterinary surgeons (Group 1), and seven farm assurance inspectors (Group 2). The two assessor groups met and received training on different dates, and viewed the same 12 video clips of sheep showing a wide range of behavioural expressions in varying indoor and outdoor situations and housing systems. For each clip assessors scored the sheep expressions on each of the 12 QBA terms using a Visual Analogue Scale. Principal Component Analysis (covariance matrix, no rotation) was used to analyse assessor scores, both for Groups 1 and 2 separately, and together in one all-assessor group. All three analyses identified that over 70% of variance in sheep expression was described by two main components. For the all-assessor analysis the first Principal Component (PC1, 49% of variation) ranged from 'content/relaxed/bright' to 'distressed/dejected/tense', while PC2 (31%) ranged from 'agitated/responsive/anxious' to 'dull/dejected/relaxed'. The 2 Principal Components identified by Groups 1 and 2 when analysed separately, were highly similar. The level of agreement between assessors in each group was evaluated using Kendall's coefficient of concordance (W). This produced W values of 0.83 (PC 1) and 0.84 (PC 2) for the all-assessor group, values of 0.90 (PC 1) and 0.86 (PC 2) for Group 1, and of 0.78 (PC 1) and 0.91 (PC 2) for Group 2. All values were significant at P < 0.001. These results indicate that two trained assessor groups achieved high levels of inter-observer agreement using a list of 12 prefixed QBA terms developed for sheep. This study is the first to investigate QBA as a tool for assessing sheep behavioural expression, and its results support further exploration of the feasibility and validity of applying this method to the assessment of sheep welfare.

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