Variability of Manson and Leaver locomotion scores assigned to dairy cows by different observers.

The gait scoring system developed by Manson and Leaver was used by five experienced observers to assess the gait of 83 milking Holstein-Friesian cows in a live recording session, and video recordings were made. The agreement between the scores of the observers at the live session, and between each observer's scores at the live session and a video session, were compared at three levels of stringency. The scores of the observers were highly variable at all but the least stringent threshold - whether a cow had a score of less than 3 or 3 or more, that is, whether it was not lame or lame.