Small Ruminant Research 104 (2012) 156–162 Contents lists available at SciVerse ScienceDirect Small Ruminant Research jou rnal h omepa g e: www.elsevier.com/locate/smallrumres Reliability of body condition scoring of sheep for cross-farm assessments C.J. Phythian ∗,1 , D. Hughes, E. Michalopoulou, P.J. Cripps, J.S. Duncan University of Liverpool, Faculty of Health and Life Sciences, Institute of Global Health and Infection, Department of Epidemiology and Population Health, School of Veterinary Science, Leahurst, Neston CH64 7TE, United Kingdom a r t i c l e i n f o Article history: Received 14 August 2010 Received in revised form 21 July 2011 Accepted 5 October 2011 Available online 24 October 2011 Keywords: Sheep Body condition Scoring Reliability Welfare a b s t r a c t In order to use body condition scoring as a cross-farm assessment tool, it is important that different assessors can consistently grade sheep along the same scale. This paper exam- ined the intra- and inter-assessor reliability of three trained and experienced assessors who independently assessed the body condition of 141 Lleyn, Cambridge-cross and Welsh Mule-crossbred ewes using full- or half-point scoring precision of a six-point ordinal scale. Assessor reliability was evaluated using percentage (%) agreement, weighted kappa ( w ), and Kendall’s coefficient of concordance (W). Kruskal–Wallis one-way analysis of variance and graphical representation of the data were also used to examine for assessor bias. The on- farm studies found that the intra-assessor reliability of an assessor, who provided training in the scoring method, was higher when half- (96%,  w 0.7, W 0.7) rather than full-unit scoring precision (79%,  w 0.6, W 0.6) was used. Similarly, a higher level of inter-observer agree- ment was found when two additional assessors applied half- (94%,  w 0.6, W 0.7) rather than full-unit scores (93%,  w 0.4, W 0.4). Consequently, the effect of a brief re-calibration exercise on the between-observer agreement for the assessment of full-unit body condi- tion scores (BCS) was examined. Prior to the exercise, the paired agreement between two assessors and the trainer ranged from 68 to 78%,  w 0.3–0.5, and W 0.4–0.5. Following the re-calibration exercise, the level of inter-observer agreement increased to 75–93%,  w 0.4–0.7, and W 0.4–0.6. No significant effect of assessor bias was found (p > 0.05). However, most sample sheep were identified within the mid-range of body condition (BCS 2–3), which affected the analysis and interpretation of reliability data. Overall, the results sug- gested that trained and experienced assessors reliably scored the body condition of sheep using both half- and full-unit scores, and that a period of re-calibration may offer a feasible means of maintaining the consistency of cross-farm assessments performed by different assessors. © 2011 Published by Elsevier B.V. 1. Introduction Body condition scoring is a subjective technique that assesses the proportion of fat and muscle in the live sheep ∗ Corresponding author. Tel.: +44 0117 331 9315; fax: +44 0117 928 9528. E-mail address: C.J.Phythian@bristol.ac.uk (C.J. Phythian). 1 Current address: Veterinary Clinical Science, Dolberry Building, Uni- versity of Bristol, Langford, BS40 5DU. (Jefferies, 1961; Russel et al., 1969) and is widely accepted as an indicator of past nutritional status (Caldeira et al., 2007). The method is used as an on-farm tool to moni- tor and inform changes in flock management and nutrition (Jefferies, 1961) and a set of target scores has been recom- mended for certain key periods in the sheep production calendar (Russel, 1984). In addition, body condition scor- ing of sheep is a key animal-based outcome that is applied as part of routine veterinary clinical examinations (Lovatt, 2010), flock health planning programmes (Sargison and 0921-4488/$ – see front matter © 2011 Published by Elsevier B.V. doi:10.1016/j.smallrumres.2011.10.001