Grading of shoulder ulcerations in sows by biopsies

Shoulder ulcerations can be graded postmortem from 0 to 4 on a pathoanatomical scale. However, veterinarians and farmers express difficulties evaluating the grade of the lesions antemortem. Accurate grading is needed in order to comply with veterinary instruction in relation to the Danish legislation, stating that sows with shoulder ulcers grade 3 or 4 must be kept loose and have access to soft bedding. Thus, the aim of the present study was to evaluate if biopsies from the center of a shoulder ulcer can be used to point out animals for which an intervention must be initiated. Postmortem, a punch biopsy was sampled from the center of the ulceration or from the tissue overlaying the tuber spina scapula. Afterward, the shoulders were cross-sectioned and evaluated grossly and histologically ("gold standard"). In total, 121 shoulders were included in the study, and the diagnostic value of a punch biopsy in grading shoulder ulcerations was evaluated. The results showed a sensitivity of 0.78, a specificity of 0.98, a positive likelihood ratio of 38.36, and a negative likelihood ratio of 0.22. The agreement between the cross-section evaluation and the punch biopsy was found to be 0.90 by calculating the Cohen kappa value. In conclusion, a single punch biopsy from the center of an ulcer is useful for determining the grade of a shoulder ulcer and can be used to facilitate the identification of sows with ulcers requiring an intervention.