Analysis of six spatiotemporal variables derived from pressure mat measurements: exploring their use as discriminative diagnostic tool for detecting piglet lameness

Abstract

Lameness is one of the main problems in modern pig industry. Apart from economic losses due to lower productivity and survivability, lameness severely impairs the animal’s welfare. In pigs lameness is often underdiagnosed due to the limited time spent observing individual animals and the absence of a fast, sensitive and appropriate diagnostic tool. Recent studies show promising results using different limb pressures obtained by a pressure mat in detecting lameness. In the present study pressure mat analysis has provided data on the variables stance duration, step duration, step length, stride duration, stride length and stance percentage. After training sound control (n=21) and lame piglets (n=9) to trot over the pressure mat, two valid runs were registered and the data analysed using the purpose build program Pawlabeling. Average left/right asymmetry indices (ASI) for the fore- and hind limbs separately for each of the six variables were analysed in a Mixed Model using IBM SPSS 21 with piglet as random factor. Significantly higher ASIs were found in both the affected and non-affected side (front/hind) of lame piglets compared to the controls for stance duration. Remarkably, the non-effected side of lame piglets showed the highest ASI in all six variables in comparison with the ASI’s of the control piglets. This might be due to the less adequate compensation between ipsilateral compared to contralateral limbs. No differences could be found for the ASIs of stride duration and stride length. Although these four pressure mat variables appear to be able to discriminate between lame and sound piglets, the practical applicability remains to be determined and is expected to be poor, due to the complexity of data analysis and lack of reference values.