Short communication: Design and validation of a hygiene score for calves.

The objective of this study was the establishment and validation of a scoring system for calf dirtiness. Defined areas of the belly, side, and rear of the calves were scored according to the percentage of dirtiness: score 1 ranges from 0 to 10% of the area (no or little soiling), score 2 from over 10 to 30% (medium soiling), and score 3 applies to soiling of more than 30% of the area (heavy soiling). The scores of the individual regions were summed up to yield the calf hygiene score (CHS) ranging from 3 to 9. The validation of the CHS was performed by 5 veterinarians on 42 calves. It was validated for its inter- and intra-observer-reliability and against a standard method created by image processing of photographs of calves. The agreement between the observers and the standard method was weak to moderate with kappa values from 0.58 to 0.67. Inter- and intra-observer reliability resulted in a moderate to strong agreement with 29 of 36 kappa values between 0.60 and 0.89. The CHS was thus successfully validated as reliable and could be a useful tool for herd health management.