Donkeys have a limited repertoire of non-specific signs displayed when in pain or sick. This study looked closely at donkey behaviour during the progression of different diseases with the aim of improving pain and sickness recognition.
Video footage of a group of 79 donkeys at The Donkey Sanctuary was obtained for 6 months; where 45 diseased cases observed. Due data completes, four cases were selected [Cases A) with respiratory disease due to herpes virus (n=2) and Cases B) end-stage cases (hyperlipaemia, n=1; chronic laminitis, n=1)] plus four healthy controls (n=4). Cases A were observed for 8hrs on day -10 and -1 prior to disease onset (day 0 = first veterinary visit) and during treatment (day 1, 5 and 10). Cases B were observed for 8hrs on day -7, -3 and on the day of euthanasia (day 0). Total time (minutes) performing 47 different behaviours were compared between (painful/sick vs. healthy) and within donkeys using chi-square or fisher’s exacts tests.
Diseased donkeys in cases A and B spent on average 10% more time (range, 3 - 17%, p<0.01) with a lowered head carriage compared to controls. Conversely, they spent 15% less time (range 6 - 34%, P<0.04) with their ears in combinations (i.e. each ear in opposite direction), thus meaning ears were more static and unresponsive. Ear changes were subtle but were the earliest indicators of pain/sickness in the observed donkeys. Cases B compared to the controls spent 31% more time in recumbency (range 7 - 60%, p<0.01), and 40% less time eating (range 1 - 64%, p<0.01). The reduction in total eating time was not substituted by any other oral behaviour (e.g. drinking, grooming, licking, and investigative behaviours), where drinking and grooming were greatly affected in the donkey with hyperlipaemia. Finally, abdominal effort was only observed in cases A and tended to reduce with time on treatment (p=0.06).
Donkeys are working animals of great importance worldwide, and these results highlight useful behavioural changes that can be used as monitoring signs of pain/sickness in these animals. The potential use of these signs warrants further studies in greater and more diverse donkey populations.