Vertical dimensions of suspended horses

P>Reasons for study: The dimensions of anaesthetised hobbled horses during suspension and transfer onto the operating table are unknown. These data are required for the cost-effective construction of equine surgical facilities. Objectives: To measure the distance from the toe to dependent back margin (Bsusp) and poll (Psusp) of anaesthetised suspended horses and correlate them with readily obtained measures from standing animals. Methods: Digital photographs of suspended horses were taken in the anaesthesia induction box at a fixed position that allowed trigonometric determination of Bsusp and Psusp. These values were linked with body mass, height at the withers (Wstand), the length of the crest from the poll to the withers (crest) and of the back (back) from the withers to the crop, by deriving an equine morphological index (EMI) using principal component analysis. The EMI and other linear variables were then subjected to single variable regression analysis. Results: EMI was 0.531mass((kg)) + 0.528Wstand((cm)) + 0.469crest((cm)) + 0.468back((cm)). Bsusp was most accurately estimated using the expression Bsusp= 118.71 + 0.128EMI while Psusp was most strongly associated with Wstand, i.e. Psusp= 46.9 + 1.01Wstand((cm)). Conclusions: The height of suspended horses at the most ventral margin of the back and the poll can be estimated from measures taken from the standing animal. Potential relevance: The data will allow the more informed planning and construction of equine surgical facilities in which mechanical hoists are used.