Repeatability of a skin tent test for dehydration in working horses and donkeys

Dehydration is a serious welfare issue for equines working in developing countries. Risk factors such as high ambient temperature, heavy workload and poor water availability are exacerbated by the traditional belief that provision of water to working animals will reduce their strength or cause colic and muscle cramps. As part of the welfare assessment of 4889 working horses and donkeys during 2002/3, eight observers were trained to perform a standardised skin tent test. The prevalence of a prolonged duration of skin tenting was 50% in horses and 37% in donkeys. Two studies investigated inter-observer repeatability of skin tent test techniques, using a total of 220 horses and donkeys in India and then Egypt measures of agreement with a 'gold standard' observer varied from 40 to 99%. Simplifying the test by reducing the number of possible scores for skin tent from three (immediate return of skin to normal position; delayed return up to three seconds; delayed return more than three seconds) to two (immediate return of skin to normal position; delayed return of any duration) did not improve overall repeatability of the skin tent test. Potential reasons for not achieving high levels of agreement include variations in assessment method, assessors' previous experience, subjective demarcation between score categories and biological variability.