This paper proposes an approach to use pain-relevant pathologies to enhance our understanding of the clinical and behavioural signs of pain in donkeys and outlines initial results of this ongoing investigation.
The methodology is summarized as follows. Trained veterinary clinicians examined live donkeys under two situations: A) before being euthanized due to a terminal illness or reduced quality of life (n= 347 sedentary donkeys in UK; DU) or B) when about to be slaughtered in an abattoir (n=164 working donkeys in Mexico; DM). The animals that represent populations in terms of age (years) for DU and DM respectively, were: <5 = 0.5%, 31.7%; 5-15 = 4%; 67.7%; 16-20 = 6%, 0.6%; >20 = 89.5% and 0%. For sex were: stallions 0.5%, 44%; geldings 52.2%, 8%; females 47.3%, 48% for DU and DM respectively. The body condition was: <2 =18.5%, 44.7%; 2.5 – 3 = 56.5%, 54%; >3.5 = 25%, 1% for DU and DM respectively and the girth was: 115 cm ±SD 9.6, 112cm ±SD 7.3 for DU and DM respectively.
The clinical examination (CE) included the oral mucosa, heart & respiratory rate, rectal temperature, plus an evaluation of 6 demeanours and 47 behaviours/signs that could relate to pain. At this point an overall pain visual analogue score was derived (VAS 0cm = no pain to 10cm = the worst pain). At post-mortem (PM), lesions/pathologies were noted, grouped by system-organ/tissue, ranked (mild, moderate, severe) and classified according to the following potentially painful pathologies: 1) trauma, 2) inflammation, 3) over-distension 4) perforation/ rupture, 5) stripping/ ulceration, 6) adhesions, 7) swelling, 8) exposure of sub-chondral bone. From these observations a second VAS was produced.
Raw correlations from the two populations showed that donkeys given a higher VAS at CE and PM presented with a greater severity of lesions in more systems as well as a higher heart rate at CE than those donkeys with a lower PM VAS. Moderate to severe pain identified CE was often recognized as severe pain at the PM stage. These initial observations show promise, and so further analysis will be done to test the relationships between pain indicators and pain pathologies.